In part II of the LS3/5a essay I will share some thoughts about choosing the right amplifier as also illuminate some of the specific construction details.
The KEF T27 tweeter
Looking at the tweeter of a LS3/5a is somewhat strange….after we fought with the velcro fixed Tygan grill of the speaker we will see a strange looking (tea strainer) cover and there is no tweeter visible. But beliefe me – it is there….;-))) First lets talk about the grills….the frequency response of the LS3/5a is measured and constructed with the grills in place – so it is NOT recommended to get rid of them – as the speaker construction behind the grilles is everything else than beautiful it is also a good fashion statement to let the grills where they belong. The same has to be said about the tweeter cover….I once I read in an internet article, that it is necessary to get rid of them to achieve more treble energy – the opposite is true…. The vented covers raise the sensitivity of the tweeter instead of dampening the latter!!!! The KEF T27 is made out of Mylar foil……it is the same material chosen by the microphone manufacturers for their capsule membrane and…..yes – it is the same material our beloved Quad “membranes” are made of. It was not so common at the end of the 60ties (last century) to use synthetic materials for speaker development – so KEF stood out as one of the first manufacturers who thought about new materials. The T27 was nearly 10 years a sort of reference in its segment – a lot of different speaker designs were made around this legendary tweeter. This little gem is able to reproduce frequencies above 40Khz – something which is also not too common in our modern days. With the implementation of the LS3/5a dividing network the speaker features a slight raise toward the highest treble. It is the opposite of what we will find with the Quad ESL 57 which has a frequency roll off starting at 15 Khz which takes care of a slightly rolled off highest treble performance. The LS3/5a renders the treble in a completely different way. If we enjoy to use moving coil carts with a slight emphasis in the region of 15 – 20Khz (high frequency rise typical for most moving coils) with the Quad ESL 57, we will be more satisfied using the LS3/5a with cartridges which domesticate such behaviour. In other words – a top notch Lyra, like the Etna SL is a dream to use together with the Quad ESL 57, in contrast to that the LS3/5a loves cartridges like the Koetsu Urushi Wajima for example. As we are now aware of this special character of the LS3/5a in the treble department – we must avoid any gear – be it an amplifier, preamplifier or source component which has a somewhat tilted up treble performance….
The T27 is surrounded by a thick felt square which prevents the sound waves to become diffracted at the enclosure and the surface of the speaker. That is important as we already discussed in part I of this essay the tremendous omnidirectionality the LS3/5a has to offer.
The tweeter is electrically secured by a resistor in front of the latter (15 Ohm model) – this thing can get really, really hot – and sometimes – if you disassemble a LS3/5a, you will see some burnt damping foam around the position of this resistor. It can happen that those things are burnt – if you are lucky, it is just the resistor and not the whole tweeter…. A blown tweeter will resulting in buying two new (old) ones, because those tweeters were matched as a pair. And if you buy two new ones it is a good idea to measure their resistance (of the functioning one) because as you can read in part I – different tweeters (electrically) could be used with different tabs of the autoformers…..so you have to search for a replacement pair which fits the technical specs of that particular pair originally used in your specific speaker to get the same treble response once adjusted at the crossover board.
The KEF B110 woofer
The B110 is a legend – it was one of the first speaker chassis made completely with a high damped synthetic material. KEF was searching for a lightweight as also robust material with a very good inner damping. They designed a completely new material to achieve that – and called it Bextrene! The very first B110 chassis had a membrane surrounding made of neoprene – later KEF opted for a rubber surrounding which was more consistent and easier to manufacture. If you look at the B110 woofer of any original LS3/5a, you will observe that it is mounted from the backside, which is totally uncommon in speaker design. If we want to achieve a time aligned behaviour of both speaker systems we would opt normally for the opposite, than mounting the bass chassis behind the plane of the tweeter. The LS3/5a crossover addressed that specific mounting position so that we will hear an astonishing phase coherency between the two speaker systems. In fact the crossover point is located around 3Khz so it is chosen in a very critical frequency region were our ear is very, very sensitive (Fletcher / Munson curve), but we will not detect any phase anomalies while listening to a proper installed LS3/5a. The B110 is a long throw woofer system to compensate for its small surface and size. Do not be afraid if you once observe the woofer moving while you are listening to some deep and strong bass impulses – what you see is normal;-))))…..If you overdo it, you will hear a loud Pock Pock sound, which is the voice coil former that knocks at the inner side of the magnet….so it is time to decrease your listening level.
The B110 gives us in the LS3/5a an amazing midrange performance – you can characterise the LS3/5a as a full range speaker with a tweeter on top….The whole important midrange spectrum is covered only by the B110! The woofers are also matched as a pair in our beloved mini monitor – so if one is defective – you are in for a very, very long search! If your B110 looks dirty – please be advised that it is not a good idea to use any liquid to clean the damn thing. Bextrene reacts not too good if it is mated with windex cleaner or pure water…so let the thing like it is – get rid of the dust and thats it!
The listening height should be adjusted so that your ear is located virtually between the tweeter and woofer position – if you sit too low, you might detect some strange phase anomalies, if the position is to high, the sensational imaging abilities would suffer seriously.
The Crossover
As I explained in part I – every manufacturer of the 15 Ohm Ls3/5a made its own crossover. Most of the very early models used autoformers which were wound in house by the specific manufacturer. Later on the British company Drake delivered all licensees with their autoformer model leaving out Spendor – they used their own stuff till the 15 Ohm era was at its end. All LS3/5a crossovers share a distinct complexity. If you are a proper High End freak – and peek inside of such a dividing network – most of us would say – that cannot work – nor will it sound good….but the reality shows us every time we listen to these little speakers, that the BBC did an amazing job – the LS3/5a is one if the most important speaker designs of all time – and this is not my humble opinion only….
The parts of the finest LS3/5a 15 Ohm incarnations used throughout the circuit were top class in those years…..do not mess with them! I know that it is easy to find monster High End foil capacitors in the audio accessory shops today – but I can assure you – every moded version does loose its magic – and at the end you have destroyed an original! Let the things like they are – watch out for strongly used parts and try to replace them with the same type once used in your speaker (one of the reasons why in the strong far east scene they collect also parts of the LS3/5a…..). If you disassemble a LS3/5a you will aware of how complicated the whole thing was built. If you change the order of some washers or forget some of the rubber O rings, the little diva will not be air tight anymore….
Everything which is present and mounted in a certain way is not an option, it is very, very important – there is no place for tuning work or trying to better the performance other than using a better position in your room or better equipment to drive the little diva.
The amplifier
The classic LS3/5a has an impedance of 15 Ohm which is totally unusual today. The maximum power these speakers will handle is around 25 – 30 stable watt. If we buy a little transistor amplifier which is able to produce 50 watt at 8 Ohm – the same amp will deliver 25 watt at 15 Ohm…keep that in mind. A transistor amp which works near its clipping is the best way to destroy any speaker – so you have to search for something a little bit beefier than 50 watt….the impedance figure of the LS3/5a is not so much loved by transistor electronic.
The opposite is the case if we discuss 15 Ohm impedance together with a tube amplifier. Our tube amp might have output transformer taps which are made for 16 Ohm…. To understand the advantage of a high impedance speaker mated with a tube amp I have to explain things a little bit more. The outputstage of our tube amp has naturally a high impedance, it varies a little bit from tube type to tube type – but generally it is a high impedance figure. The output transformer is used to adjust for the high tube output impedance to be matched to the low speaker impedance. If we use a 4 Ohm speaker a lot more windings are necessary to achieve that as with a high impedance speaker, as the LS3/5a is. Finally a high impedance speaker design is a very good match for any given tube amplifier as also OTL (output transformerless) designs!
As the LS3/5a is not very sensitive, you might think it is not a good idea to pair the speakers with low powered tube amps – but the opposite is true. The high impedance of the speaker compensates for its restricted sensitivity! A LS3/5a is not a good match for a SET amp like a 300B or even more so a 2A3 – both have too little power to drive the speaker to sufficient sound pressure levels, but a 6L6 GC push pull design or an EL 34 amplifier – may it configured in triode mode or as a penthode works like a charm. Keep in mind the little box is very, very accurate to the source – so if you think of something cheap and mediocre – the whole system will sound accordingly….If you opt for a transistor amplifier there are also great models out there which have a legendary status. The Naim chrome bumper amp range comes to mind or legendary class a amps from Britain (Sugden, Musical Fidelity A 1000) or the US (ML or Cello) as also the amazing Lavardin of our days. The latter is one of the most musical transistor amps that can drive a LS3/5a! But if we have the chance to listen to one of the rare 15 Ohm specimen today I would opt for a nice tube amp!
A tube advice
With a tube amplifier we have the possibility to voice the amp to our liking – and if we listen to a LS3/5a using tube electronics it is time to praise the legendary Mullard MC1 ECC83. This is one of the oldest European ECC83 type of tubes and it sounds so damn fantastic with the legendary British speakers, if I did not know it better, I would guess they were constructed for each other. The Mullard MC1 features the one of a kind wrinkled glass surface as it also has a square getter construction and long narrow grey plates. To spot an original MC 1 we have to observe the lower segment of the tube – we will find there an etched code with the type MC1 and a number which should start with a capital B for the Blackburn production plant. The MC1 is not the only long plates Mullard ECC83 – the successor was named F92 and has also an amazing sound. To mate the Mullard MC1 with the proper ECC82 Mullard (phase inverter / preamplifier) things get a little bit exotic. The holy grail of all Mullard ECC82 is the military version of their ECC82 called CV 491 – and this is it….A Mullard CV 491 Long Plate together with its stablemate the MC1 is truly amazing. These tubes have a one of a kind bass gestalt. Full and tight as also very, very colourful – the dynamic abilities of the deepest octaves are astonishing. The midrange is reference class with a slight emphasis in the lower midband – which brings vocals in their three dimensional gestalt right in front of our speakers. The presence is somewhat defensive and opens up nicely towards the treble and air – I would call that a classic tube sound. The stage a Mullard is able to render is big and bolt – in this parameter it is one of the best tubes I know. I use them both in My Air Tight ATC2 HQ preamplifier together with a GEC CV 4005 rectifier and this preamp drives the ATM4 which I already described in my essay about the 6L6 GC – both amplifiers are mated with two Chartwell I and the performance is stunning!
Keep in mind that all the old long plates Mullard sound completely different than the short plates incarnation made from 1960 onwards. The short plates – especially the I63 type is very smooth and even rolled off in the treble department which cannot be said about the long plates Mullard tubes of the ECC83 and ECC82 family. The downside of choosing these legendary British made signal tubes is their rarity and the high prices we have to pay today. But think about it in a different way….if you spent €600,- on a power cable or a signal cable the benefit would be much, much smaller as if you opt for such an outstanding electron tube!!!! These legendary Mullard long plates types are unmatched till today – no modern construction comes even close!
Quad ESL 57 versus LS3/5a
If you like the sound of a Quad ESL 57 but you cannot place it in your room – than the LS3/5a is the closest thing to the original Quad in existence. It does not sound the same (of course not) – but the most important aspects of the reproduced music is cut from the same cloth. The LS3/5a can reproduce deeper frequencies with more impact if we position them in front of the long wall of our listening room (reed part 1 of this essay), the Quad on the other hand delivers its deepest frequencies with more accuracy and authority. Both are very, very fast reacting speaker systems, but the Quad is able to reproduce the leading edge in a fashion no other speaker can muster (unless we use also a ribbon or electrostatic construction). The LS3/5a can beam the sound into the room with an amazing omnidirectionality while the Quad is very much restricted in this discipline. If you want to listen to your favourite music with your family or friends and not alone, the LS3/5a is the better option, because you can enjoy their beautiful  performance also if you are not located near the sweet spot. Both speakers are able to deliver an astonishing resolution – but they do it in a different way. The LS3/5a is able to reproduce the treble and air section of the reproduced music in a nearly unlimited style, the Quads do not have that outstanding treble performance, instead of that, they are able to deliver the smallest shades of colour as also a tremendous amount of micro dynamic variations without having such an unlimited high frequency performance. Some people opt for a super tweeter in conjunction with the ESL 57 to get exactly that kind of “unlimited” treble performance – but till now I am not aware of any solution which does not destroy the tremendous rightness this speaker has to offer.
The LS3/5a can play a little bit louder than the original Quad ESL but we cannot speak about a real grown performance showing macro dynamic shades – far from that. That brings us to the biggest disadvantage both speaker systems share….the maximum sound pressure level and the rendering of really big dynamic swings. Both speakers will deliver an undistorted signal up to 100 – 104db  (in 1m) – and both are rather insensitive – the figures are nearly equal. If you can live with this restriction you will be payed off by so many seldom found qualities in the whole speaker market today, that it is my strongest advice to listen to one of them – maybe it will be your last pair of speakers……
Both constructions do not change their frequency coherence while played with varying volumes – so you are able to enjoy your favourite music in some intimate nighttime listening session in its full glory. If you are a mixing or mastering engineer this characteristic is highly appreciated and seldom found in any speaker design. The Quad shows even a miraculous feature, because it does not change its loudness proportional (logarithmic function) to the various listening distances – which I never detected with any other speaker system. What makes both constructions very special is the ability to get the complete midrange right. The Quad is in this regard a little bit more unforgiving, If there is any colouration in this frequency section present the electrostatic speakers will show you that in such a clear distinction, that you are amazed and sometimes shocked. Both speaker systems are able to render a soundstage you never will forget, the LS3/5a does that in a more bolt fashion, while the Quad has a more analytical gestalt with a tremendous pin point accuracy. The LS3/5a might be a little more spectacular if you do not listen carefully – maybe that is also achieved by the crazy discrepancy between the acoustic performance and the physical size of the little box.
To mate a LS3/5a with a sub woofer is not a good idea – I never heared till today any implementation of a separate woofer which  lets the masterful voicing of the little gem intact. No sub can react in such a fast way as the little Bextrene B110 chassis can do – so you get heavy phase anomalies in the upper bass – which will destroy a good portion of what a LS3/5a is all about.
Happy listening
E. Strauss
Medialux 
Great article! i am a Stirling owner and i really like the approach and the deep dive. thanks a lot!!!
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Enjoy your Stirling LS3/5a, they are also amazing!!!!
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Dear Christos,
enjoy your music with the Stirling – an amazing speaker!!!!
And thank you for your comment.
Kind regards
Ekki
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I have a Mcintosh mc275. would these work in a fairly small room? mine is 12.5 by 14.5 feet. I think the quads which I jove would not work in this smaller room
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Der Doug,
the MC 275 is a powerhouse – you can kill a LS3/5a with such an amount of power – if you take care of your listening level, it would work! – With the MC275 there is always the problem to get good KT88 tubes – in may opinion nothing – and I mean NOTHING sounds like a real GEC KT88…..and they are very, very rare! With any new KT88 or 6550 the MC275 sounds slow and al little bit awkward….
Your room size should be no problem – but keep in mind – use the long wall…..
Happy listening
Ekki
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I will be importing the newly reborn Rogers LS3/5A (15ohm). As stated above, the only alternative to my own refurbished Quad 57’s (Electrostatic Solutions)!
Robyatt Audio
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Dear Robin,
great to hear that you import the Rogers among your other outstanding products! As you can read in this blog – I share your thoughts about LS3/5a and Quad ESL 57 – both have a midrange which is so real and unforced – and both can deliver a stunning 3D sound experience. Till today I have not found any other speaker regardless of the price, which sound sooo natural than these two britisch classics.
Thank you for your comment and Information,
kind regards
Ekki
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Agreed! My two fav speakers. I also enjoy my Stax F81’s the only speaker that makes the Quad sound muffled by comparison but nowhere near the dynamics or weight. I also listen to TAD CR1 MKII’s! For mono I have a fully restored Quad Corner Ribbon!!!
[cid:836B7763-21AF-41C1-8EC0-2331A5B6A547]
Robin Wyatt
Robyatt Audio
http://www.robyattaudio.com
info@robyattaudio.com
(866) 576-3912
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what a great article! Superb!
Many thanks!
You did mention the modern reincarnation from Stirling and Falcon, but what about Graham 3/5 and 3/5a?
Markus
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Dear Markus,
thank you for your kind words…..
Graham has two models which are constructed around the BBC LS3/5a – one is called LS3/5 which has nearly nothing to do with the traditional BBC sound and it´s design – it is made with a different approach. The Graham LS3/5a is more inspired by a the classic BBC design – but it did not get any BBC approval as far as I know – so it is not a drop in replacement for a 11 Ohm LS3/5a as the Stirling is (because it got the BBC approval). I only mentioned LS3/5a speakers which git the BBC approval…
I hope that answers your question
Kind regards
Ekki
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Thank You, Ekki, and what about the newer V3 of Sirling Broadcast?
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I understand that theLS3/5 was at the original BBC design of this speaker.
KEF changed the bass driver, so a modified version was made, hence the /a.
I have read a review that thought the Graham Audio LS3/5 sounded better than the LS3/5a, it could be considered that the BBC’s very good alternative was in fact their second choice.
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Dear Markus,
I have not heard the V3 – nor do I know that it is already available??? – If it is BBC certified – it might be interesting – if not – it is than something else.
Have a nice day,
Ekki
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Yes, the Stirling V3 is available, but I have no informations if it also got the so-called BBC certification.
Finally there is another modern 15 Ohm reincarnation, propably without BBC approval:
https://www.rogers-hifi.uk/rogers-ls35a-classic-speakers
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Dear Ekkehard, thank you for these two great articles. I am the lucky owner of a pair of Harbeth LS3/5A that I picked up in St. Petersburg, Russia several years back from a musician. They are now paired with my Arcam Delta 290 amplifier and the sound quality and reproduction is just incredible. I used your tips on speaker placement from the wall which has also helped to richen the sound. Great speakers and still going strong. Regards and seasons greetings from Moscow, Steve.
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Dear Ekkehard, have you listen to the Rogers LSB1 sub with the Rogers
LS3/5A?
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Greetings….
yes I tried the Rogers sub with the LS3/5a and did not like it – ever with the KI method of placement the speakers are less coherent and in the lower midband I can detect a lot of colouration wich is absent if you use these speakers without any sub. Also different modern constructions did not convince me – mostly they are too slow and therefor you get phase anomalies which are completely absent without those devices. Hope that helps – have a nice day
Ekki
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Thank you for explaining why a 15 ohm LS35a speaker with 83 dB sensitivity sounds so good with tube amplifiers. I have been using a Chinese made 50 watt KT88 push-pull integrated amp to drive DIY Falcon Acoustic LS35a speakers (9 inch depth) along with a REL subwoofer. Sounds fantastic to my ears. Recently I substituted a 2 watt Chinese made SET amp (EL84, 12AX7). At the same 11 o’clock volume setting I get the same SPL output (90 dB at 6 inches using a smartphone app). Sounds even better with more holographic imaging. Can you explain why this is so? I am considering one of the Decware (U.S.) SET amps…2 watt model (6P15P-EV, 6U1P/6922) or 6 watt model (EL34, 6U1P/6922). Based on your article I should opt for the higher powered (more expensive) model?
Appreciate your advice,
Raymond Soo
Ontario, Canada
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Dear Raymond,
sound pressure level drops with the square of its distance – so it is important wich distance the I phone had to the speaker. At the same time it is also important how big the room, in which the speakers are positioned is….as it is also importand how strong the room is damped (furniture, carpet etc.) And last but not least – the dynamic range of the source material is also part of such a calculation in real world listening (not sinus tones – but real music). The LS3/5a is made to work with amplifiers, which can deliver stable 25 Watt. If we analyse a transistor amp, its behaviour at different impedance figures is different as with a tube amp. Both react in opposite ways to a given impedance. A transistor amplifier for example might be deliver 50 Watt at 8 ohms – the LS3/5a has 11 or 15 ohms – the letter will react witrh the amplifier in a way, that the output power drops to nearly 25 watts. With the tube amplifier it is different – because tube amps love high impedances – they see an easy load – and can “breathe” more freely. If you use a SET amp – it is normally layed out in pure class A – if you use a 300B you have normally 8 Watts on disposal. If you listen to your LS3/5a in a nearfield situation – it might be enough power to handle not too dynamic source material. To double the volume you are listening to, the speaker needs to produce 6db more sound pressure level. If you calculate my above statement regarding distance and sound pressure level drop – you need a loooooooot more power to gain 6db more sound pressure level if you increase the distance between you and the speakers.
And another thing is very important…..a tube amp reacts totally different at the end of his linear power output. The distortion such a device generates is much nicer for the human ear (harmonic distortion) – and the distortion is generated in a much smoother way. A transistir amplifier does not generate a high amount of harmonic distrortion – and its distortion figure rises steeply – not smooth. Hope that gives you a better understanding…..have much fum listening to this great little speakers – E. Strauss
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Thank you for the clear explanation and all the factors that affect sound level at listening position. I got 80 dB level at listening position 8 ft away. Probably should retain my KT88 push pull tube amp then. An EL34 SET will only yield around 6 watts of output. I’d rather keep my speakers than go with higher efficiency ones just to use an SET amp.
Raymond
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Hello,
I’ve got kind request regarding ls3/5a placement.
My main music system is singing via Electrovoice Sentry III (the other room) and BBC monitor is something new for me.
Unfortunately I found your excellent article just after I had bought my minis – new Graham Chartwell ls3/5a (instead of these I should probably look for the 15ohm Falcons (?)
My current (temporary) room is 3,2m x 5,5m. Speakers are located on the long wall. Toed in approx 6-7*
I am a fan of travelling through the room with my speakers (that is really hard work 🙂 previously I had also Altec 19 and JBL 4343 in my main room).
ls3/5a are much easier to be moved but still can not find the perfect position…
Nearfield listening is quite interesting then I place the speakers 1,5m apart (center to center of the front baffle) and 1,7m each speaker to the listening position. Speakers are placed 1m from the front wall (still measured to the front center of a speaker).
Interesting but… not comfortable and the sound (rock music) is sometimes overhelming in such kind of placement.
Could you suggest some positions and distances worth to be checked please.
Many thanks in advance!
Rafal (from Poland)
PS. My amp is Sansui AU-999
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Dear Rafael,
sorry for the delay in answering your questions – it was a very busy week….
First of all, the Graham LS3a is a different kind of speaker – it uses different chassis – so I cannot comment on them…
A vintage or original LS3/5a should be placed on the long wall – as you already did. The distance to the rear wall should be 1m minimum….If you detect a bass bump – it is necessary to increase the distance to the rear wall. The bass response is also dependant of the width of the base of your stereo triangle. As closer the base is (distance from both speakers) – the more pronounced the bass response will be. You can place the LS3/5a oin a way, that you get 1,5 – 1,8 meter base width – without getting problems with your center fill – because these speakers radiate a lot. If you found the correct distance to the rear wall and a perfect stereo base width – the listening position is now given – if you place them in a stereo triangle. The toeing in must be carefully adjusted – it is typically between 5 and 7°.
It is not needed to use these speakers just for nearfield purposes – they are as good in using them also in greater distances to your listening spot. What matters is the acoustic in your given room!!!! As the LS3a radiate tremendously – the sourrpunding walls should be far away – or acoustically treated – the goal is, that the direct sound pressure produced by the speakers should reach your ear much faster, than any early reflection. If he room is very lively it could degrade the sound tremendously. The speakers can disappear and are able to generate a 3 dimensional illusion – which is spooky.
It is interesting, that you had JBL 4343 – I mixed 10 years with these speakers in a studio near Hamburg…they are true classic monitor speakers, which can deliver sound pressure levels near the real thing!!!!
Hope I could help
have a nice day
Ekki
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Hello again,
I am talking about this one.
Is it really so different than the others 11ohm?
https://www.grahamaudio.co.uk/products/ls35a/
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Dear Rafael,
yes it is completely different – the original 11 Ohm LS3/5a used Kef chassis – the Graham does not…they tried to mimic the frequency response – but it is a different speaker which looks like a LS3/5a. If you have the chance to compare a original pair of 11 Ohm to the Grahams – you know what I mean. even the cabinet is made in a different way and differs in the thickness of the material, which is used. The network inside is also completely different – so what should I say???? – It is named LS3/5a – but in my book it is a minimonitor which is inspired by the BBC original – but it is not an exact replica nor is it a replica…it is something different.
The Kef B110 chassis is very, very special – as is the tweeter with its Mylar foil dome….
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Dear Ekki,
Many thanx for all of your tips and sharing some key points.
Thank you for explaining a few major differences between the ls3/5a.
I need to investigate more…
Honestly speaking I’ve only read before „Art Dudley Listening Falcon & Graham LS3/5A” and then have much better offer for Graham than Falcon…
Heard them both but in different locations/rooms… sounds not so different, Falcon were a bit brighter, Graham more neutral for me… but both I would say in the same league…
Thank you so much!
Now I try to look for a vintage pair.
Cheers!
Rafal
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Dear Rafael,
do yourself a favour and try to get an original LS3/5a – I agree – the Falcon sounds to forward in the treble region…it is made a close as possible to the original specs and material – but – do not ask me why – it sounds a tad too bright. Try to find a good Rogers White Tag 15 Ohm or a Spendor Gold Tag 15 Ohm or a Harbeth 11 Ohm. The legendary Chartwell original is very, very rare (Chartwell 1) – as is the Rogers gold tag…if you can get a Rogers black tag – it is also one of the best LS3/5a ever made. The later Rogers 15 and 11 Ohm are not anymore so well made – they often have problems with their gaskets – because the wood is bent by humidity. a good starting point is a 11 Ohm Harbeth – which is not soooo rare – and it is a damn good version of the original LS3/5a. Harbeth made one of the best enclosures – and in the 11 Ohm period – any brand uses the same crossover and chassis – all made by KEF. With such a well made Harbeth in good condition, you end up with less money, than with a brad new Falcon – and you have a real vintage LS3/5a with a drug like sound.
If you get involved with the tremendous qualities of this little speaker – you should get a good 25 Watts tube amp – this is a combination, which is in my ears amazing (as you might read in my essays…). Tubes, wich can sound magica with a LS3/5a are:
EL 34 construction (an old Marantz 8 for example….)
6L6 GC construction
KT66 constructions (a pair of Quad Monos is magical)
Do not get confused – these little gems show you exactely what you feed them with – so it might be at the end a system, were the speakers are not the most expensive part…..that is normal!!!!
And finally – the stands are of tremendous importance – the original Foundations are not anymore available – Music Tools in Italy makes a very, very good copy. This is mybe the best LS3/5a stand you can buy today (I use them myself – and tried various other types). Put the speakers with 4 small (!!!!) balls of Blue Tak onto the top plate of the Music Tools (Tool One) and give them a little pressure. Use SMALL balls – because the bottom of the speaker must be able to swing. Do not use any sort of Spike between the stands and the speaker – nor other expensive isolation devices – just a small portion of Blu Tak…that is all you need. With the right stands, you are in for a big surprise – the bass cleans up and ability to beam without being located raises to a sort of performance normally found only in electrostatics. Such an installation is a very, very good addition to something as a JBL 4343 also old vintage 15″ Tannoys….
If you are patient you can reach a sort of sound and naturalness – a vocal performance which is seldom heard in such a quality. Also true is – LS3/5a are not the best to listen to hard Rock Music stuff – Metallica is something for the big guys such as 4343 – but if you like to hear some classic music, singer songwriter, vocal stuff, Jazz, and pop music it is amazing!!!! Listening to some Radiohead tracks of their “In Rainbows” album is unforgettable.
I whish you all the best for your journey…take your time – do not waste your money – sometimes the good stuff is not the most expensive stuff….sometimes it is….
Have a nice day
Ekki
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The new Rogers LS/5A is as good a version as ever been made read Aart Dudleys review. I own multiple versions of them. That all of course are close but I must say the new Rogers is the sweetest one yet!
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Dear Ekki,
This is real treasure trove of information!
Many thanx for sharing.
I start searching of Harb’s right now.
Friend of mine is a huge collector of tube equipment from 60/70’s and turntables.
Now I play on my Electrovoice Sentry III with Pioneer PL70 II turntable and Heathkit W4-AM Tube Amp Mono Blocks… but I can have almost everything from him 🙂
Regarding stands… that was probably the other wrong recommendation to use light openframe. Thats why I have perfect copy of Linn Kan stands. I know and use small balls of Blue Tak.
PS. Radiohead is in my top 5 🙂
All the best!
Rafal
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Dear Robin,
if I compare the new Rogers to their last editions of originals with 15 Ohm as also the following 11 Ohm models, that I would agree. But if I compare them to a pair of Chartwell 1 in very, very good condition – I have to disagree…
If someone want to have the biggest bang for the buck – I would recommend a pair of Harbeth 11 ohm in good condition any time – you can get them for around 1200,- – 1500,- Euros. So I would think – that this is a safe route for someone, who already bought a sort of LS3/5a copy, which has near to nothing to do with the original stuff made under licence of the BBC. Art (which was one of the best HiFi columnists ever – I miss him soo badly) – did nit compared those new versions – or interpretations against some of the legendary classics – be it a Gold Tag Rogers – a Black Tag or a Chartwell 1…..The new Roges is better than the Falcon in my book (others may listen in a different way) – but I hear a not so small variation in comparison to some of the best vintage ones.
I have a pretty good collection of original LS3/5a and was able to compare them in my system with new models – be it the Rogers, the Chartwell or the Stirling….
As I am a professional audio engineer – I use Harbeth 11 Ohm for my job on a regular basis. I can trust them nearly blind (of course not in the bass ) – which I can hardly say about any new incarnation. The Falcons are too sharp in the upper Midrange and treble, the new Rogers do something in the midbass, which an original LS3a does not. They are designed to produce a sort of more “spectacular” bass – which might be nice for some HiFi enthusiasts – but it is a much higher sort of colouration in the very important lower midrange, which I do not like.
The original construction is more restricted in the lower register – but they have less colouration (even they have the midbass bump – but less strong).
Also while having critical listening sessions with the new Rogers I can detect a less elegant sound reproduction at the crossover point between the two chassis – which is something I can also measure. If you compare them to what the market has to offer in terms of size and performance…
Happy listening
Ekki
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I have Jim Rogers actual pair of LS3/5A’s my father bought them from him at his home. They are pre Tygan grills. The new ones are better but I put that down to 60year old crossovers and drivers. My Chartwells are broken in like yours I am sure but I feel when these new Rogers have a few hundred hours on them they will be the first choice. I do like Kef Anniversary edition too but it’s different
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Dear Robin,
as you mentioned – running in those little queens of mini monitors is another thing….Most of the old ones suffer from bad gaskets – even more so, if they very opened by their users….sometimes the wooden frames get bent with moisture leaking into the enclosures – with such a sort of holy vintage – even the very famous badges are in them – you have just a washed out shadow of what they can bring to the table. I did nor detect so many problems on the dividing network circuit board, as all caps are fold types. With the resistors which sees a lot of heat it is a different chapter (which was solved in the 11 Ohm versions). As the LS3/5a is everything else than a efficient speaker – most of them were played pretty much at the limit – which often means that the resistors which sees a lot of heat gets bad – sometimes those things do still work – but they are totally out of specs. Today – which is very, very sad – we face a market situation with old original 15 Ohm speakers, which es only manageable for people who are very, very well educated in this field. I see more FRANKENSTEIN Chartwells or Gold Tag Roges on ebay as I like to see. In a time were a pair of original Gold Tags can reach 5000,- one should do the homework to avoid later disappointment. And yes – in exactly his market situation it is very good, that there is noch more than one opportunity to buy something new. The only case – were I think in a different way is the last 11 ohm editions from Harbeth. Till now – they are not so badly overpriced than the Rigers Gold Tag or Black Tag – or the Chartwell 1. So they are also not the target of those specialist who “rebuilt” a classic Chartwell to something which never left the factory in GB as they are mostly offered at ebay. It is maby the most risk free classic LS3a you can buy – and Harbeth was one of those, who came late to the party – but did a tremendous good job in quality control and matching those KEF chassis – so it will be my first recommendation for someone who does not want to study the LS3a in detail.
At the end we are lucky today, that after the last 11 Ohm classic left their factory – we are able to listen today again to one of the most important nearfiel monitors of all time. And it is also very interesting – that Peter Walker of Quad delivered with the legendary 57 electrostatics a midrange wich is in my book till today unmatched – the LS3/5a is one of the very rare speakers which do nearly the same trick. Thats why I named my two essays – A Midrange To Die For….which is maybe the reason why you carry both products (which is damn rare today)…
And yes – the KEF ltd editions, which closed the chapter of the classic LS3/5a history are amazing – but different (they have also a different B110 type enclosed).
Happy listening
Ekki
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My reference are restored Quad 57’s by Electrostatic Solutions. I also own a restored better that nee Quad Corner Ribbon I use with a REL 646B mono receiver and a Grey Research rim idler table and Grey Viscous damped arm loaded with a Miyajima Zero Mono
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Dear Ekki,
Once again about the speaker placement…
I’ve got room 3,25×5,5m now.
I try to use the long wall.
Also for the best holography I need around 1,3m speaker placed from the front wall.
Taking into account distance to the listening position (min. 1,6m) I’ve got nearly nothing to the back wall…
I try 1,5-1,7m as a distance apart the speakers.
Could you recommend some positions would be worth to check.
Cheers!
Rafal
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Hi Rafa,
my suggestion is – as I mentioned 1m (minimum) to 1,5m away from the wall te speakers will be placed. You should also sit not directly near the opposite wall – and than yoi need a littel toeing in of max 7° and a base which hast to be figured out – it depends in the distances you already managed to get….the aim is a even triangle – the base could be a little smaller that in a triangle with even sides…but only a little. What are you missing…..???? Hope that helps – Ekki
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Hi,
This is what I understand.
But… speakers (let me say) 1,25m from the front wall, listening position around 1m from the back wall… as a result I could have 1m to the center base of my speakers (as I said, room width is 3,25m).
That means the base is around 1,2m (equilateral triangle).
Little, I should say… don’t know about the potential issues that may occur.
-Rafal
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Dear Rafal,
1,2m base is very small – 1,6m would be much better – the imaging a LS3/5a is capable of is stunning – so in your example this image would be smaller, than it could be, if the base could be made wider. Try to check less toeing is – instead of 7° – try 5 or 3 – or even parallel to the rear wall…. – maybe you can gain 10 – 20cm with your listening position – so that you can widen the base???? – Hope that helps
Ekki
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Dear Ekkehard,
Ad an old owner and enthusiast of these wonderful mini monitors, I must say that I am very much in agreement with your analyzes and considerations. In my long audiophile journey (I’m going to the 70s) I have had the opportunity to try many of them, now I have kept two pairs of Rogers 15 Ohm, a blue / black and a white belly, very different from each other; I drive them with a Marantz 8B or an S.E. 300B (us) supported by the Foundation stands . After trying many room placements (I am not looking for bass reinforcement, but I am more interested in the extension and resolution in the high range, the richness of the midrange, harmonic release, soundstage extension and image. 3D ), I came to the near field listenig (very close) , the long distance from the back wall and the small toe in. I hope I haven’t made too many mistakes, it’s not my usual language.
Best regards, Fabrizio.
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Dear Ekkehard,
First, thanks so very much for your blog. You approach your writing with a passion and attention to detail that reminds me of Art Dudley (the highest praise I can give to another writer).
I have a couple of questions:
(1) Have you heard the latest version of the crossover in the Falcon LS3/5a? If so, did it make an improvement in that speaker’s performance sufficient to allow comparison to vintage 15 ohm versions from Rogers, Harbeth, etc?
(2) Have you heard any modern mini-monitors (Harbeth P3esr, Proac Tablettes or DB1, etc) that approach what the LS3/5a can do in terms of imaging and sound staging, reproduction of voice and acoustic instruments, and natural sound?
(3). Is there anything one can do to limit the compromises inherent in placing the LS3/5a along a short room wall?
Thanks for you consideration.
Tom Dressler
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Dear Ekkehard,
I had hoped for a response to my questions above. Any thoughts you might have would be appreciated. As always, thanks for your superb writing.
Tom Dressler
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Dear Tom, sorry for my delay – I have a lot of work these days….now, lets get to your questions….: No, I have not heard the latest crossover incarnation of the Falcon Acoustics – so I cannot report on this. What I heard is the classic Falcon 15 Ohm remake – and this one does not sound quite like a 15 Ohm LS3/5a vintage speaker. It has a somewhat more pronounced lower treble, which can be aggressive in some situations – the speaker is shouting at you in this frequency range, which is the reason, why I do not liked this incarnation of the 15 Ohm LS3/5a so much. And yes I heard a lot of modern mini monitors, such like the Harbeth P2 ESR and also the Proac Tablettes. Both are amazingly good speakers – but you cannot compare them directly to a LS3/5a – both sound somewhat different – which does not mean worse! But the classic 15 Ohm LS3/5a does some tricks, the more modern speakers cannot match – and they are amazing teammates for tubed amplifiers, which cannot be said of the other two speakers. Regarding your placement question….I do not know any trick which can match the frequency response of a pair of LS3/5a placed on a long wall. It is simply physics – and such is hard to overcome. Some people mate the little British Queen with sup woofers – be it the construction Rogers once constructed or more modern high tech stuff. But till now I never heard a sup woofer ensemble which does not harm the amazing ability to speak with one voice and to disappear as a speaker. All sup systems I know of, do serious harm on the phenomenal timing coherence the LS3/5a has, if it is used stand alone. So the only trick to enhance the bass register is placement….sorry! – Hope that helps – all the best, Ekki
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Dear Ekki,
Dear all,
I would kindly ask if that one could be taken into account. Reviews rather good and the price I need to pay is so nice now.
I know… not a vintage classis only the Chinesse beast 🙂
https://www.line-magnetic.eu/en/products-line-magnetic-en/integrated-tube-amplifier-line-magnetic-en/lm-34ia-integrated-tube-amplifier-push-pull-el34-class-ab-2x40w-detail
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If you are patient enough – you can get a nice little Mcintosh MC 240 one day – and if you know a little bit about tubed gear – you can refurbish this old legend on you own. This would be one classic ensemble which can blow your socks off….so think twice…all the best, Ekki
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Dear Ekkehard,
I am the owner of a recently diy’d LS3/5a. I bought of couple of the Stirling built-up and tested front baffles, then built the 12mm birch ply, removable back and beech filleted boxes with 4mm bituminous pads and to-spec foam damping. All in all, very carefully built and I think probably quite similar to the Stirling V2 as described in their material.
Anyhow, I’m in a rather large L-shaped room with v-ceilings. Probably many and complicated room modes. After doing a lot of experimentation with 2-3m placements I gave up. I then switched to near-field experimentation. When I sit at the end of one of the arms of the L with the speakers about 1m apart and 1m away, the magic suddenly happens. It is best firing each speaker towards its respective ear. Then, I hear all the traits you describe. An incredible size of sound stage and a depth and power of bass not feasible. The speakers are not there – I hear no artifacts at all which appear to locate them.
Incidently, I am driving them with (again DIY’d) FirstWatt B1 buffer and M2 combo.
Thank you for your articles – most informative and interesting and and I shall certainly try your advice if I can get the speakers into a more conventional rectangular room at some point.
DaveW
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Dear Dave….good to hear that it works not only for me….;-))) – This can be a legendary system – and what you describe, seems to be exactly that….have much fun with your music collection – because thet is, what it is all about – listening to great music!!! Ekki
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Sorry, meant 9mm birch ply in the above.
DaveW
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wow. nice writeup. been using rogers 15ohm ls35a since the late 80s. honestly havent heard vocal reproduction done better on the other 40 or so speakers i have listened to in my journey so far. just heard abt the quad 57s today and may just try them out someday. just wondering, they are not like regular speakers right?
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Dear Michael, no – ESL 57 are electrostatic speakers, which is a completely different technology! If you have the chance to place the Quad ESL 57 – you are in for a treat! – So I would opt for a listening session in your own room….all the best, Ekki
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Just some details that have no affect on the sound of the LS3/5a.
First I believe bextrene is not a KEF developement but was around before its use in speaker cones. The BBC is responsible for the use of the material in speakers. KEF was one of the 1st companies to use it after the BBC found how to use it. It was used in BBC speakers like the LS5/5 which used a 12″ woofer and 8″ mid range designed by the BBC and built for them. I believe the main reason they went to bextrene is that it was more consistent driver to driver than paper that was used before. That’s sort of interesting because the B110s used by the BBC in the beginning were quite inconsistent and most were returned to KEF for being out of spec.
Secondly bextrene is not that well internally damped. That’s the reason for the shiny coating on bextrene drivers. It’s polyvinylacetate(PVA), a coating used to dampen the B110. Application of the coating is especially critical inmaintaining consistency driver to driver since the PVA is applied by hand and consistency is thus an art form.
The BBC was aware of the pluses and minuses of bextrene and continued looking for cone materials with fewer compromises and they came up with polypropylene about 10 years later which was used in the next generation of BBC speakers.
By the way consistency speaker to speaker was just as important to the BBC as excellent reproduction. They had thousands of speakers and expected to just grab two random speakers of any model and have a good stereo pair without doing any special matching.
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I bought my Rogers ls3/5a 2 years ago and im so happy with it. Amplifier is Accuphase E-650, a perfect match 🙂
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Well, i had ls3/5a in 90s……went through Odysseys of Speakers and fullrange
i just got 2 pairs Spendors 11 Ohms and must say they again sound terrific on SE 300b Amps with Tango OPT and western E. 300b valves…….extremly liquit,
amazingly sweet treble , Details and great imagin.
Pre Amp is SP8 AR, Tango SUTS
for low /Mid volume listening over Hours its a hard to beat Speakers Combination..i run 8 Ohm Tap on SE 300Amp which works nice at 11 Ohm, spendors…….for Bad Press Lps look else, just feed them with great ,clean vinyl.
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Herr Strauss thank you so much for your articles, truly amazing work! I’m running my Falcon Acoustics gold badge LS3/5a with a Lavardin isx. I have had my eyes on a Leben CS300xs to which I wanted to use instead of the Lavardin. Even though it is running the ECC83 tubes, I now realize, after having read your article, that the Leben is under powered at 15 W 8 Ohm, which will be around 8 W into speaker’s 15 Ohm. Do I get this right or is there something I am missing?
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Der Mario,
thank you for al the great feedback regarding the blog…
The Leben is slightly underpowered – but there are also LS3/5a freaks out there, who are using a 300B SET – which has between 6 and 8 Watts….it depends on the size of the room and the music you are listening…If you use the LS3/5a in a near field situation – 15 Watts are enough – if you use them in a larger room – it is a compromise. AND…which is more important….the Lavardin is in my book an amazing match – to do it clearly better needs something else than this little Leben!. Tubes does not mean automatically that the sound will get better…not if the sparringspartner is a Lavardin…!!!!!
Hope that helps….
All the best
Ekki
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Thank you for your quick reply!
I agree that the Lavardin Isx does sound great. I am less impressed by the build quality of it. The fact that it is generating an audible thump in my Falcons at each power off has me worried that it might be doing some damage :S
Do you have any recommendations of tubed integrated brand/model that I could be exploring as a next step?
Best regards,
Mario
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Maybe try an Acoutsic Masterpiece AM 201 – it is not anymore made – so only available used….And the thumb while switching the Lavardin off is not normal….
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The Acoustic Masterpiece AM 201 is still being made, however it seems to be a Hong Kong based daughter company of Air Tight who makes them.
Will contact Lavardin after the holidays to see what’s up with the thump.
Thank you for all your help! Keep up the good work and happy new year!
All the best,
Mario
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Dear Mario, the AM 201 is still on their webpage – but it is not made anymore (it is discontinued since nearly 2 years)…and yes – it is an Air Tight Design made in China – but – if you use fine tubes, it sounds very good. And it has 24 stable watts…which is what the LS3/5a needs. t is made with a parallel push pull configuration using 8 EL 84…which makes NOS tubes a little bit problematic – because finding 8 mathched Mullards is like winning the lottery…;-))) I can give the German distributer a call – maybe they have reinvented the AM 201 again – but I do not believe that….
If you search dealers and not the A&M webpage you will see that they all claim that it is not available anymore, which is also the info I got from the distributor here nearly two years ago….But sometimes you can get such a unit used…so good luck. Regarding the Lavardin….there is something wrong…maybe with the amp – or there is a heavy potential (due to power cabeling in your setup) on your interconnects…I do not have seen ANY Lavardin which does behave like you described it…Please try to de connect any sources – just the amp and the speakers – and try again…
If the thumb is still there – please try to turn the power plug in your outlet 180° if that is possible in your country…if it is still there – that it is the amp…
If it is gone – reconnect the cabeling step by step – and always turn on and of after every change…
All the best
Ekki
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There is a swedish dealer who seems to stock them for a little over 3000 Euros:
https://www.akkelisaudio.com/forstarkare/air-tight/airtight-acoustic-masterpiece-am-201.html
If I am completely honest I do worry about the resell value during a potential future upgrade. There is a prejudice against Chinese made hifi it seems. I think it is unfair when it comes to the pricier stuff but that’s how it is..
These last couple of days I’ve been on a CS300XS frenzy, reading everything that is Leben. Now one reviewer suggests that the “..new Genalex Gold Lion N709 EL84 reissue tubes even better than his vintage Mullard EL84s”.
Have you tried these? 🙂 The link to the article:
https://positive-feedback.com/Issue43/leben.htm
Regarding the Lavardin:
I’ve tried everything you’ve suggested. I even shut off all of the electricty in my house except for the room where my Hifi is. Disconnected all the mains in that room except for the amplifier and tried again. Nothing helps.
I have called the swedish Lavardin distributor who promised to call me back. Still waiting for that call. Been also trying to call Lavardin directly but nobody’s picking up. It is holiday after all so I’m not surprised nobody’s working 🙂
Best regards,
Mario
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Dear Mario, yes – resell value – especially in HiFi is a story on its own..and Acoustic Masterpiece stuff never get the same stability as real Air Tight stuff, made in the small manufacture in Osaka / Japan. Of course not. And I share your opinion about that….maybe that is one of the reasons why as Jack Miura entered his fathers company this stops immediately…who knows. Regarding the Gold Lion stuff….forget all the review guys…they must write this rubbish…because no other stuff is available. If I write an article in German Image HiFi, all the distributors do not like to see if I am talking about NOS stuff – and I can understand than – because it is not easily available anymore. BUT – to sind the song of the industry is not my cup of tea – and I never – read NEVER had a single case were a Electro Harmonix relabeled tube was near the quality of even the worst NOS (speak beginning 80ties production) tubes – letting alone a true blackburn Mullard EL 84 or Telefunken….Most of the EH stuff is packed in different famous labeled enclosures and only slightly different from the basic tubes they sell. If you compare the internal structure of a EH EL 34, a Mullard branded EH a Genalex branded EH and a Tung Sol branded eh – it is the same internal construction – what they change or experiment with is coatings. – And….if you use legendary names – you should know, that Tung Sol never made a single EL 34…but thats a different story. The special thing with Genalex – I mean the real vintage legend is – that they did not build a normal EL 34 – their EL 34 variant was called KT77 – due to patent stuff – they build their kinkless tetrode technology in a EL 34 compatible tube…the new genalex EH stuff is a plain EL 34 construction. – So….you can do whatever you like – but do not complain that I did not warn you;-)))))
regarding the Lavardin – you have to speak with one of them…or maybe better – call your dealer were you bought the amp….
All the best
Ekki
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I use my Rogers new edition Ls3/5a with a custom Tektron 300b using Telefunken AC2 input tubes Panasonic 274A rectifiers and New WE 300b’s. Small room they sing. In my larger demo room the Rogue Atlas Magnum III is stunning on them. The Atlas can use KT66/77/88/90/120’s EL37/34’s 6550 6L6/6n3CE’s. Choose your Sonic preference.
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Happy new year!
In response to your tube comment I can only say that the world of tubes seems to be a complicated one. Fickle NOS tube stock mixed with sneaky branding of companies who have nothing to do with the original production etc..
I am also fascinated by Robin Wyatt’s comment that he uses a Tektron 300b with his Rogers. The Tektrons have 7W in 8 Ohms!
I’m also listening in a small room… Perhaps a 15W tube amp would do.. If I decide to venture that route.
Came in contact with Lavardin, They assured me that the noise in my speakers during shutoff is part of the normal operation of the amp. Apparently they do not use relay switches that cut the speaker outputs at shutoff.
What they instead do is lower the volume of said noise so as to not cause any damage to the speakers.
All the best,
Mario
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Google
SMSL VMV A1
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Hello ! Thank you for your excellent and thorough articles on the LS3/5a. I have a pair of Spendor 15ohm 5xxx series and they sound divine. I use tubes exclusively…either a SET 845 (Triode TRV M845SE) or rebuilt Eico HF81 (6bq5) or rebuilt McIntosh 225 (7591). Keep up the good work !
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Hi Ekki,
the number of all the different versions of this classic monitor, which have been built during the last decades, is a bit confusing.
I would like to come back to Rogers. You have mentioned the White Tag, Gold Tag, Black Tag, and “later” 15Ohms models.
I have a Rogers 15Ohms model made by Swisstone UK, they have black labels with golden letters, reading distributed by Pirol Germany.
Is this a “later” model according Your classification?
Best,
Markus
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Dear Markus, yes that is a later model – with the Pirol LS3/5a (Distributor) you have to be careful while buying a 15 Ohm – because Pirol bought and sold nearly the whole “pseudo 15 Ohm” from Rogers. These speakers have original 15 Ohm labels at. the back – but inside sits a 11 Ohm speaker. That happened as the BBC changed the specs – and Rogers had finished enclosures still labeled in stock – so there are some pseudo 15 Ohms in existence – and nearly all of them, were bought and later distributed by Pirol. To be sure what is inside – you need to open the speaker…..all the best – Ekki
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i think another way to tell is by the serial number. numbers lower than a certain number (cant remember now) are 15ohm inside and out. but yes, as you said, the best way is to open and inspect.
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Serial number is P1619.
I opened the speakers and measured – with the crossover connected – 6,2 Ohms across the woofer and 7 Ohms across the tweeter.
I could post a photo, but no idea how this works…
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Dear Markus, if you opened the speakers (be careful with that – because they need to be air tight….) you can easily see which version it is…use google and observe a typical 15 Ohm crossover – it should have at the top of the board 3 Autoformers – the 11 Ohm version does not have these – the circuit board looks totally different – google 15 Ohm Rogers crossover – and then you see immediately, what I mean. All the best – Ekki
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Dear Ekki, many thanks for this information. As far as they say, all 15 Ohms versions in the past had autotransformers instead of coils; my late “pseudo 15 Ohm” Rogers do not have transformers indeed. Nevertheless, they prooved their qualities in my collection over 25 years already, and I prefered them in direct comparison with modern versions such as Strirling or Falcon.
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Dear Ekki et al,
I would like to come back to the different crossovers of the historical models.
Did Harbeth use autoformers for the 11 Ohm version (circa 1987)?
Best, Markus
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Dear Markus, all 11 Ohm models do not have autoformers anymore. The crossover for the 11 Ohm LS3/5a was standardised and was made by KEF. So you will finde roughly the same crossover (depends on the year of manufacture) in all 11 Ohm speakers. But that does not imply that they will sound equally good, because you still have the screening of the chassis and the manufacture of the enclosure. In both parameters Habeth was one of the best – so there might be a good chance the a well preserved Harbeth sounds much better then some 15 Ohm LS3/5a. They are in fact some of the best vintage LS3/5a you can get. All the best – Ekki
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Ekki, the mystery about my “pseudo 15 Ohm Rogers” seems to be solved finally: They also have a (11 ohm?) KEF B110 SP1228 with a standard KEF crossover with resistive ladder, like the old Harbeth version. The UK cabinet is 1/2″ plywood, and they sound very fine.
Many thanks
Markus
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Hi Markus, the B110 should never have 11 Ohm….but if you have the 11 Ohm crossover, which is easy to spot (missing autoformers etc.) your LS3/5a is one of the pseudo 15 Ohms….A lot were sold through the German Pirol distributor….this issue comes from the fact (story is handed down…..) that the change from the traditional 15 Ohm speakers due to unacceptable tolerances in this time in the history of the LS23/5 surprised a lot of the licences building companies. So Rogers had a charge of enclosures ready to be fitted ith parts and already badged with the 15 Ohm sticker….So they put the new 11 Ohm standardised crossover in those enclosures. There are not so many of them floating around. The German Pirol company must have bought a big charge of them – mostly in black…because we can find a lot of them with the Pirol sticker at the back. Another special story is the Chartwell II. As Rogers bought the rest of the Chartwell company, they tried to establish the Chartwell brand under their own roof. So….Chartwell had some chassis already matched and crossovers already finisher (15 Ohm) so that Rogers could use them in their own enclosures – badged with Chartwell. Ist was at the same time, Rogers brought out the white tag LS3/5a…. So at the beginning we find Chartwell II with Chartwell crossover circuit boards, Chartwell matched chassis (which were not available anymore at this point in time, the white belly took over) and also some finished Chartwell crossovers…Later in time we face Chartwell II speakers which are internally like Rogers White tag but with older speaker chassis inside (matched by Chartwell)… So it is somewhat complicated….That is also the reason, why a Chartwell II is waaaaaaay cheaper on the used market then an original Chartwell I…. Hoe that helps – all the best, Ekki
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ok so far, but to what is the definition “11 Ohm” referred?
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…..The overall impedance of the whole loudspeaker as usual of course. Please try to understand the crossover construction of the LS3/5a – not a single chassis of the little queen has 11 or 15 Ohm….we ALWAYS speak about the standard averaged impedance of the speaker system. The impedance is frequency dependant – so with all speakers we average them to determine the total impedance of a given speaker system.. The impedance of a 15 Ohm LS3/5a never drops below 8 Ohm – which makes it an easy load for a tube amp despite its low efficiency. In fact you it might be one of the best choices to drive an LS3/5a be it an 11 Ohm model or the 15 Ohm one. With transistor amps it is not such an easy task with that specific high impedance speaker, as a transistor amp rated of 50 Watts at 8 ohm, delivers roughly half of that power in an 15 Ohm load. So the amp will drive the LS3/5a with just 25 Watts. The speaker is rated for exactly that power – but 25 Watts of a transistor amp gives you next to no headroom anymore. And if a transistor amp does not have such headroom, you will hear clipping at higher volumes on snare drums for example. This is not good for the speaker itself – keep in mind – you will more easily destroy a speaker with a too small amp – then with a too large one. With a tube amp I would suggest something like a nice 6L6 GC construction or EL 34 as also KT66….All of them will have around 30 – 35 Watts…which is pretty much what the LS3/5 will like to see from a tubed amp. In the transistor camp I would suggest somewhat more power…so 75 Watts at 8 Ohm might work (depends on the construction of the amp). Great matches are in the tube amp camp (naming just a few…): Mcintosh MC30 dual Mono, MC240, MC225, Marantz 8B, Marantz Model II or V (expensive), Quad II mono, Air Tight ATM1S, Air Tight ATM1, Air Tight ATM4, Shindo Haute Brion etc…All the best – Ekki
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Thanks for the explanation. I guess there is a technical standard how to calculate the “nominal” or “average” or “rated” impedance from a measured impedance curve. For us (tube lovers) more important than the nominal impedance are the lowest dips within the impedance curve. Years ago John Atkinson showed that in BOTH (“15 Ohm” and “11 Ohm”) classical versions the lowest dips are around 8 Ohms….
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Dear Markus,
yes the nominal impedance is a quasi industrial standard – at the moment I know of no speaker manufacturer, who does it in a different way. And yes, the lowest impedance “dips” are around 8 Ohm – but 15 Ohm and 11 Ohm LS3/5a are not identical in its impedance curve so ist also the sound. In the normal push pull ballpark there is pretty much every design wich can deliver around 20 – 25 Watts able to drive the little queen in a satisfaction way. Am always stunned how precise these little speakers are, so that they can show very clearly which kind of electronic you put in front of it. The same is true for cartridges or digital sources. So finding a good amplifier / preamplifier system with the right tubes to match the LS3/5a can cause some headache, if you want to have the highest possible sound quality. If something is only slightly coloured in the mids the speakers will tell you immediately….they also do not like most of the modern tube rubbish with all this hard and strained treble Gestalt (without any real resolution and airy frequencies). all the very best – Ekki
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During the years I could compare my vintage “pseudo 15 Ohm” Rogers at home with several modern reincarnations, always driven by the same tube amps (KT66, 6L6, EL34, EL84). There were huge audible differences among the speakers.
Here we have to keep in mind: Any vintage 3/5a will not sound as it were new, because all the parts have undergone aging: Capacitors and resistors maybe out of original specification, the rubber suspension and membrane has changed the physical characteristics, the wood has dried etc….
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Dear Markus – hmmmmm aging….I read that regularly…but, what should age if we think about foil capacitors, resistors and auto formers???? If I measure the capacitors of my Chartwell 1 they are exactly it the tolerance range once given in the technical data sheets. The only thing which could be a problem is the large resistor a the edge of the crossover board which could get pretty hot due to very loud listening levels and high frequency stuff….sometimes it burns some of the damping foam. This is a part we must consider to replace if it looks like it was treated badly. In such a case the condition of the tweeters is also questionable….hopefully the resistor gave up first, which is not always the case;-))) With chassis it is a matter of treatment. If the speaker was used to partying – we might face some problems, but as the Bextrene B110 have no foam surrounding they will pretty much keep their Thiele / Small parameters (if the rubber was not put in direct sunlight, which is not so easy due to the grills). The tweeter is pretty much in specs if it was not treated as mentioned above. So if you have a vintage LS3/5a in good condition – no partying no studio work, it will sound to a very high degree as it left the factory. BUT….as the chassis deviation from KEF was pretty high, the BBC dream to have direct replacement with any LS3/5a regardless from which company it was made, might be very unrealistic. There are also a lot of differences in the construction of the licensed companies. Spender for example smashed the circuit to adjust the tweeter on the crossover – so no adjustment is possible here – instead they did a precise screening and measurement for their speakers. The enclosures are also pretty much different from all the manufacturers. Late Rogers models are prone to suck air – as they are not built anymore in the same quality once was typical for Rogers. The parts on the 15 Ohm crossovers were different from manufacturer to manufacturer and of course during the period of time these speakers were made. And even the chassis changed a lot over the time – a white belly B110 is different then the first neoprene B110 used in the Gold Tag Rogers etc….The raging story is often told by manufacturers who try to achieve today an original LS3/5a – be it Falcon or also other manufacturers. If we compare a brad new Falcon after lets say 100 hours playing time with an original (that is important – I will come to that later…) Gold Tag Rogers or Chartwell 1, we will detect a different sound in the treble. and that is not a matter of “burning in”…it is there and it will never go away. Falcon reacted to that lately – and they got better! The biggest problem is – if we listen to vintage “originals” we never no, if the tweeters are still the ones, which were once selected for this particular LS3/5a and adjusted accordingly on the crossover. So we see a lot of modified LS3/5a today – or to make it clearer….we see more modified LS3/5a vintage speakers today then original ones. And not seldom we see also fakes…because the prices skyrocketed in the last years – so it might be interesting to put some different stuff in a Gold Badge enclosure and sell it for 5000,- or more! Today – if a tweeter is burnt or broken, we all have a big problem – because old vintage parts are rare – and we have to measure the stuff – and adjust accordingly (if possible) at the crossover. Some tweeters came from different speakers as the KEF chassis was pretty en vogue at this time. So, the biggest question is, what are we comparing today to modern LS3/5a incarnations – or different vintage models????
Then we have also with vintage LS3/5a a huge quality variation – at least over time. Thankfully Harbeth started to bring all the lost quality in chassis matching (now with the help of modern laser and computer technology) and woodwork back to the table. Maybe that is one of the reasons, why 11 Ohm Harbeth are in my book one of the best incarnations of any LS3/5a (if they are in original well preserved condition). People like to have today the overly hyped “best” and most “famous” LS3/5a, the Gold Badge Rogers, the Chartwel 1 and the Audiomaster – and maybe also the Black Tag Rogers….but if those are Franken LS3/5a it is hopeless.. The biggest chance to buy something really original in good condition would be a used Harbeth….but that is not so popular – because the cult is missing somewhat. That reflects also und prices…a pair of well preserved Harbeth with back finish will reach maybe 1200 – 1500,- a Chartwell 1 – often a Franken Speaker – starts at 3000,- and way more. The last really good condition Gold Tag at ebay US I am aware of, was sold for 5500,- in 2015!!!!!! – I am not observing every auction of course – but if I am looking at some offerings – there are mostly modified speakers on the market – or such in very, very bad condition. That is the strongest argument to buy some of the new models….if they are made in a way, that it is close to the original. All the best – Ekki
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Just unplugged my Dunlavy Aletha’s and brought out the 15 ohm Rogers LS3/5A’s (mid 4,000 sn’s) I purchased in October, 1978 while i grad school in Indiana. Original box, receipt $425 for the pair, and Swisstone warranty and inspection/testing record. Yes, they are just that good on vocals after 45 years. My wife suffered when I traded a pair of Klipsch Heresy 1’s that she loved,… Oh well.
They work well with Mcintosh transistor integrated pieces like the 5100, 6200, and what I’m using this evening, a MC-6900.
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