Air Tight ATE 2 – a full tubed full function preamplifier

The company:

With the Japanese company Air Tight there is a lot to discover which is completely absent in todays High End scene. Product running times of more than thirty years without any MK II or upgraded version of a given amplifier is something we wont find at any other company today. If a piece of gear is developed, than it IS developed, there is no reason for any change, which says something about the quality of the development. Miura San is one of the last living legends in the audio scene, meanwhile in his mid eighties, he has a lifetime of experience in building tubed audio equipment, a sort of deep understanding seldom found in todays fast changing market were every year new completely unknown people want to tell us, they found a new technology in amplifying an audio signal. With some new technologies, like digital amplifiers, that might be true, but with tube technology???

Miura has a sort of calm style in managing his company and developing audio gear. Things need time, countless listening tests, which was very clearly seen with his Opus 1 cartridge, which Air Tight brought out two  years ago as a cooperation project between Matsudaira San (My Sonic Lab) and Miura San of Air Tight (A&M ltd.) to celebrate the 30. birthday of the company. Miura needed more than 3 years from the first prototype, shown to the press and some “insiders” for listening tests, till the final product entered the market. And between the first prototype and the final candidate, there was much more different, than just the styling of its beautiful appearance. Instead of that Miura changed a lot of details which had a tremendous impact on the sound of the final product. It is astonishing how a man in his mid eighties could achieve such a good hearing as also spending so much attention to the finest details. The fruit of his restless work was once again, as we witnessed it more than 10 years ago with the legendary PC1 Supreme cartridge, a place at the very top of todays cartridge designs. The portfolio of the small company near Osaka, which counts around 6 employees, is dedicated to the analogue music lover. There are no CD players or DA converters in existence, instead of those kind of products, Miura offers a wide range of tube pre, phono and power amplifiers, which use nearly every single famous power tube concept in existence, as the 300B, 211, EL 34, EL84, 6L6 GC and the KT88. The output power varies between 2X 8 Watts of the ATM300 to 2X 110 Watts of the ATM3 EL 34 monoblocks and is finely graduated. Not only this wide variation of power tube concepts reminds me of one of the other legends in the Japanese art of building tube equipment – …Shindo.

An indication of both companies is the fact, that the price of an amplifier has no direct influence on his sound. The smallest amp Air Tight has in their portfolio, the ATM1s is one of the finest EL 34 amplifiers I know.

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The difference in money you have to spent for the power amplifiers has more to do with the size of transformers (and their price tag) and power supplies, because a KT88 in ultra linear operation with its 2X 75 Watts needs more expensive iron, than an EL 34 amplifier, the exception of this rule concerns all single ended amplifiers. What I want to say is – in the Air Tight amplifier lineup there is no such thing as entry level and reference level in their ability to give you a maximum in soundquality! That said, things change quite a bit with the portfolio of preamplifiers – here we face a difference in fittings, be it the existence or absence of a phono sections, or the kind of outlay in which the gear is made. And even if there is a sort of range describing the quality of the different preamplifiers, there might be also some exceptions from that rule. If the little full function preamp ATC1 is mated with the previously mentioned ATM1s, (a pairing which was made for each other and was also developed together), you are in for a treat!!

The lineup includes pure line stages and full function preamplifiers with on board phono sections, as also stand alone phono preamps. The more basic (which does not mean simple or bad sounding) gear share a transistor, diode rectified power supply, as we climb up the range, we get tube rectifiers and full tube stabilisation with some of the most elaborated hybrid power supplies you will find on the market,

The Air Tight ATE2:

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Miura had the Chuzpe as an analogue lover to bring a full function preamplifier to the market, which has a full blown phono section with all bells and whistles – but he equipped the ATE2 just with one single line input. So the ATE2 is not for those audiophiles, who have a tremendous number of gear….just ONE nice FM tuner or CD player, maybe a DAC with switchable inputs (which gains the flexibility if you have more than one digital source) and you are done with the number of line inputs. On the other hand, you will find two MM inputs, switchable from the front plate, and a pair of phono direct outputs, bypassing the whole line stage with all switches, volume control and of course the tubed line gain stage.

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This additional pair of output jacks are very special and offer us different operation modes. You can plug the phono direct outputs into your favourite line stage, as you can feed the Air Tight amplifiers directly, because they all (not the ATM300) have two  switchable pairs of inputs and sensitivity potentiometers, to adjust the volume or gain. The latter will be the most pure signal flow you can achieve. With its 200 Ohm output impedance the ATE2 has no problems to drive nearly every power amplifier on the market directly. If you have a second amplifier setup in your room, those extra pair of direct phono outputs can also be used to feed a different system, while the whole full function preamplifier resides in his setup, it can distribute the phono signal fully processed (RIAA eq and gain) to another device.

The power supply:

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Miura San opted for tube rectifiers and tube stabilisatation in the power supply of the ATE2. Together with the in house produced power tranny with its 8 different outlets, we will find a single 6X4 full wave rectifier tube. Stabilistation is done with a 12BH7 double triode and a EF 86 penthode. The regulation is accomplished fully discrete using the finest components available. Miura replaces electrolytic capacities as fast as possible in favour to high voltage foil caps in the signal chain and supply voltages.  Therefor he uses the excellent  Audience (Auri Caps). Electrolytics will be found just  in the first stage of the power supply and in some regulation circuits, together with ASC paper in oil caps a reminiscence to the golden time of tube technology.

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After careful listening sessions, I opted for a GEC CV 4005 black plates in the rectifier stage, which is a British military version of the 6X4 or EZ90 (the European designation for the same tube). The two stabilisation tubes EF 86 and 12BH7 were selected with RCA 12BH7 black Plates foil d getter from the end of the fifties (last century;-)) and the legendary Telefunken EF 806S, which got this status from its use in the well known Neumann U67 microphone.

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The phonosection:

A novelty in the Air Tight portfolio is the fact, that Miura uses in each of his phono section exactly the same design – what differs is just the expenditure in its layout. The basic design features a 2 stage gain section made with 3X 12AX7 (or ECC83) double triodes. The first gain stage is made with one single 12AX7 which does just gain at this point – subsequently we will find the bass emphasis part of the RIAA curve in the signal flow,

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which is located between the first and the second gain stage to avoid noise. The second gain stage uses just one respective section of the two remaining 12AX7 double triodes, after which the signal passes the treble processing of the RIAA curve.The complete equaliser section is made by using a CR circuit, one of the simplest ways to achieve a highly accurate equalisation with a minimum of fuss and parts.

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To get a preferably low output impedance Miura designed a SRPP circuit in the decoupling stage of the ATE2 using the two remaining section of the 12AX7 (ECC83). So all in all we have 3 12AX7 (ECC83) in the phono section of all Air Tight preamplifiers with exactly the previously explained implementation. What differs is the kind of execution, the quality of the parts and the power supply. The whole amplifier is point to point wired, which also applies also to the phono section. The whole circuit is placed on a smooth copper plate, which is treated with Zappon lacquer to avoid oxidation. This copper plate has two functions, on the one hand it shields the small signals from electromagnetic pollution, on the other hand it acts as a mechanical isolation device.

The line stage:

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In the line stage of the ATE2 Miura choose ECC88 frame grid tubes . Those are naturally superior to any 12AX7 (ECC83) or 12AU7 (ECC82). With the frame grid technology the Philips group found at the pinnacle of the tube age one of the most dramatic progression in the sound quality of electron tubes. If you have the chance to peek into such a construction, you will understand that this technology signified a whole new chapter in tube design – those tubes are made like a piece of mechanical and electro mechanical art! The ATE2 uses a two stage design in their line section implemented with two ECC88 and decouples the signal with a SRPP design we already discussed with the phono section to achieve also 200 Ohm output impedance.

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The volume tracking is accomplished with one of the best possibilities next to a ladder switch, by using the very famous ALPS Japan RK 501 pot….A haptic enjoyment! This thing is extremely transparent and does not ad any coloration to the sound, as it gives you a very precise tool to adjust volume, even in very, very small increments. The stunningly even channel balance of this pot is amazing – even if it does not work in its optimal range – amazing!

Controls:

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Next to the ALPS RK 501 volume potentiometer, we will find a stereo/mono switch on the front plate of the ATE2, as also balance control and two switches for the different sources. The latter is made in a special way – you have a switch which selects line or phono, and an additional one for selecting one of the two phono MM inputs. All switches are easy maintainable if one day they need some cleaning. Both switches  do react without any noise! Last but not least we will find the power button on the right side of the front plate, which is typical for any Air Tight gear. Miura designs every piece of gear with a certain legality, the power supply sections are always at the right side of the gear as it is the power inlet.

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It is very easy to built up an Air Tight system without getting a big mess behind the gear with signal and power cables twisted together – very, well done Mr Miura! The principle of design means also, that we have to place the gear in a certain way – our goal is to get the largest distance between the power supply of our amplifier and the input section of the phono stage – and as the gear is made as it is – it is an easy task.

Tube rolling:

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As I use my beloved Quad ESL 57 with the ATE2 it is not recommended to mess up the incredible resolution and pureness of this preamp. So I opted against some very exciting Mullard long plates (MC1 long plates square getter) – because those type of tubes work perfectly with a speaker like the LS3/5a – but not with the restricted amount of highest treble energy the Quad has to offer. The KEF T50 tweeter in the LS3/5a together with the deviding network means a slight treble rise with a tremendous resolution – the T50 is able to react on frequencies over 40Khz with ease. The Quad is a different breed – the treble starts to roll off at 15Khz – and is nearly absent at 18Khz – a Mullard – as beautiful it might sound, is the last thing we need with this speaker system. One might think an Amperex would be a good choice – and yes, I tried this…. I use Amperex long plates 12Au7 and 12AX7 Foil D Getter in another preamplifier in my Quad room – but in this case, i could detect a pronounced emphasis in the prenence, which is typical for the Amperex long plates and one of the reasons for their amazing 3D abilities…. But with this specific preamplifier it was too much of a good thing…

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With the decision of proper NOS phono tubes, we also decide what kind of performance we will get regarding the noise coming from the record – all this little nasties like clicks and pops could be amplified in a way, that we will get crazy or we have a lucky smile on our face. There are NOS tubes in existence, which set these noisy signals far away from the music – they perform in such a quick way, that a click is just a short signal, with a Mullard (MC1) in a phono stage, such a click will be a real event, something I cannot live with;-))))

That does not mean, this legendary Mullard is a bad tube – far from it – but in a phono stage ist is everything else than a perfect solution!

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As you might guess – I opted for a triplet of equally numbered Telefunken ECC83 smooth plates. A tube which is sooo quiet, one of the most silent ECC83 I know. And the Telefunken can transfer those clicks and pops in something you are able to ignore – a miracle! The ECC83 Telefunken has such a balanced sound, which lets the ESL 57 shine. The bass is tight and well rendered, the mids are outstanding – maybe the reference point in this tube class (read my essay about the Telefunken ECC83 on this blog) – and last but not least we get a high unforced treble resolution, something the Quad needs so urgently! At the whole frequency spectrum the Telefunken is almost neutral – especially in the midband, which is is a MUST, if you listen to a pair of Quad ESL 57 – this little divas are able to show you the slightest amount of coloration.

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With the line tubes it was not such a clear decision, and even today, I can live with more than the single solution I finally choosed. I had some of the finest ECC88 to play with, and every single one of them has such a tremendous sound quality with some special colours, the others miss. My stash included Siemens Halske CCA, Telefunken E88CC, Amperex Bugle Boy 6922 Gold Pins and Valvo Red Label E88CC. The Siemens had the finest resolution and the tightest bass – the air this tube can deliver is outstanding, the whole amplifier starts to breathe – amazing! – But the Siemens has a slight defensive midband section, a little bit of the classic HiFi coloration. That is easy, if you listen to Jazz or Vocals as also Pop music – but if you choose one day a very good classic recording – you will detect what I mean. It is still acceptable if you listen to small orchestra music – but if you choose romantic music, like Mahler or Bruckner – it does not work…..massed strings get a synthetic touch, the overtone spectrum sounds not natural anymore….

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The Amperex has an amazing 3D rendering – it is one of the rare tubes which can tell you something about the third dimension in a given recording – you will get a real nice picture! BUT – the Amperex is also coloured –  here it is the presence area of the spectrum. This makes vocals super sexy – female singers are a sort of an erotic experience – but than you listen to some distorted guitars – and it is all over….;-)))) – The presence emphasis transfers a Metallica record to more or less something we would call noise…..yes I hear you – you think IT IS NOISE – but It is not….The guitar sound produced on this specific album is like jumping in a warm swimming pool…. It is arranged in a style comparable with a church organ – listen carefully, and you might detect this album is far from being just noise – even it is Heavy Metal!!!!!!

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The Valvo Red was amazing – as was the Telefunken E88CC – both are maybe my favourite E88CC in THIS PARTICULAR preamplifier..both share a neutral midband, both have a natural unforced resolution, the Valvo Red being a little bit recessed in rendering the highest frequencies – but not in a way, that I missed something. The Telefunken was more open, and acted quicker at the leading edge. In opposite the Valvo had a slightly more impressive bass…..if I am bored – I can change those two E88CC tubes back and forth – one month is Valvo month – followed by a Telefunken month….I started with the Telefunken E88CC!

The enclosure:

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Miura San built his gear like it was made in the golden age of tube amplifiers. There is no cheap aluminium box screwed together, instead he uses a steel enclosure of 1.3 – 1,6mm thickness welded together! After that procedere the chassis gets some solid layers of automobile paint in a baked finish. The reason for such a tremendous outlay is on one hand the perfect shielding such a faraday cage is able to accomplish, on the other hand we will detect that steel is a fantastic resonance absorber. The aluminium frontplate is just screwed on top of the steel enclosure to get a nice an stylish appearance.

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The bottom of the ATE2 is made of copper – that means that gear which stands underneath the ATE2 cannot radiate electromagnetic pollution into the fragile circuits. The whole preamp enclosure is divided into 3 main sections. One section is reserved for the power supply and separates the top deck of the ATE2 in two section using a massive copper plate.  If we turn the ATE2 over, we will find the bottom main deck, in which the complete line section is located.

The Sound:

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I own from Air Tight also the ATE 2005 stand alone phono stage, which uses the same circuit and layout as the ATE2 in its phono section. They both just differ in their power supply (and a very special MC head amp the ATE2005 features). Were the ATE 2005 uses a transistor power supply and diode rectification, as also full discrete transistor regulation, the ATE2 uses a full tubed power department.

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Both differ also in their gain layout, a consequence of the built in MC head amp in the ATE 2005…(another story…)

The ATE2 features 36db of MM phono gain, the ATE 2005 just 30db. For any comparison I had to adjust the volume accordingly – which I did. The impact of tubes in a well built power supply is clearly detectable – the ATE 2005 has a drier bass response, very tight and limitless, while the ATE2 brings a certain agility on the table with an aesthetic which is completely different from the ATE 2005. On Dancefloor, Electronic and some Pop music pieces I like this tight, deep and impactful behaviour  of the ATE 2005 very much. If we change the music style to Classic or Jazz, the ATE2 sounds more real, the bass ist more articulate, even if it is not as tight. The music beginnst to breathe, there is a sort of beauty in the bass rendering, which the transistor power supply equipped ATE 2005 cannot counter. On the other hand the ATE 2005 has a sort of openess, which the ATE2 can not muster. The Air and resolution is astonishing – while the ATE2 reacts in a smoother warmer style! Both are some of the finest tubed phono stages in existence today – and both are everything else than equal!

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The ATE2 os able to render a jet black background, the micro dynamic abilities are stunning, even the slightest shades of dynamic contrast is presented in all its glory, which is also a form of resolution, nobody speaks about today….but it is a very important type of resolution. Treble and Air resolution, which we get in spades since a couple of yers even if the whole picture drifts into analytic insignificance is one part of the story –  but what makes you sit and listen while forgetting to breathe are the finest differences in dynamic shades…I could (and do) waive the last ounce of treble and air resolution with my choice of speaker (the ESL57) but I cannot live without the finest dynamic shades – which brings – in my opinion – music to life. The ATE2 shows this ability with tremendous realism, and the ESL can transduce the whole picture in all its complexity in a very accurate way.

This preamplifier reacts very, very fast to the leading edge of a sound or instrument, and all the Quad lovers will agree, this is one of the skills were our beloved “vintage” speaker shows to most of all modern designs what attack speed is all about. You can witness the birth of a tone – what could be more beautiful….???

It is stunning what Peter Walker designed sixty years ago, which we can enjoy in all its beauty and perfection with todays elaborated moving coil transducers and high resolution (in a good way) electronics.  It reminds me of an old Leica screw mount camera with its famous Elmar 1:3.5 mated with a modern black and white film….The picture (sound picture) is in both examples a long forgotten type of aesthetics, which touches our heart. It is not a photoshopped high resolution digital picture with all its arbitrariness!!

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The ATE2 could be your last preamplifier, if you can live with just one line input, it is THAT GOOD. There might be more resolution, more bass, more treble or more macro dynamic today in the most modern and elaborated designs – but the wholeness, the natural kind of rendering this thing is capable off, differentiate real music played by real human beings from a sort of an effect dilution.

Its comparable to movie films – one needs hundreds of Avid and computer –  rendering effects to get the plot through – the other movie has just a perfect and tasteful camera mated with a fantastic script. If you have really something to say  – you just need a quiet audience…..

Think about that….

Stay tuned

 

E. Strauss

 

The Marantz CD94 – Part1 (the drive mechanism)

A musical digital player??

If we look at the CD player situation today, there is not much to write home about…. Today we have to accept, that nearly no company is manufacturing dedicated CD transports anymore. The last decade was full of CD machines which used transports originally deigned for computers or car stereo systems – the decade of really high quality dedicated CD drive mechanisms ended around the the year 2000. Since than we got a lot less for a lot more money. Any DA converter needs a proper source, and if  we skip for a moment the whole streaming possibilities, the source for a DA converter is a sort of physical media – normally a CD or a SACD. Both optical media needs a damn good drive mechanism for reading the implemented digital data – hopefully with near to no loss, low jitter, fast and secure action, isolated from vibration implemented by the player itself or from the outer world.

Maybe you asked yourself while reading CD player offerings at the used market – why in nearly every advert you will see, there is some information written about new laser mechanisms or a brad new complete CD drive which was implied in a 4 year old machine??

Now lets jump directly to the years from 1985 – 93….the time, were you sold your record player and dived into the modern digital world. You bought your first CD player – and you had during its time in your HiFi system never any problems with the CD drive mechanism – maybe the unit needed at some stage a new driving belt for the CD drawer – but changing laser mechanisms or whole drives was not a task you had to deal with – right????

You changed in that period of time maybe the player – maybe more than once, because the big HiFi magazines told you that every new generation of CD players surpasses the actual generation – so an upgrade was mandatory….  The same story is also told to us till the CD as a mass media lost its importance agains streaming solutions. But was it really true, what was proclaimed???

Philips changed the design of their CD 0 drive to the CD 1 and later on they brought out the CD9 and all these steps were not made to design something better – it was made, because they wanted to make the things cheaper. The same can be said also about the ladder multibit DAC – in Part II of this article I will come back to that story.

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Believe it or not – one of the best transports ever made was the Philips CDM 1 pro drive used in the end of the 80ties, last century – and even the first CD transport ever manufactured, the CDM 0 was a legend, regarding data integrity and fast operation. Those CDM1 pro drive mechanisms were used in the CD check machines the mastering studios used to check the digital quality of the media (digital errors). They were so good, that it was the reference, were everything else was measured against it. And of course they were expensive – made from metal cast, supplied with a sub chassis mechanism, a Rodenstock glass lens system (no plastic optics) and the speed of tracking though the index of any given CD was miles ahead of nearly anything which came later to this party. In one word – it was maybe the epitome of a CD drive mechanism – but it was too expensive to achieve a complete player, which could compete with the price of a cheap coffe – machine at the point of sale – electronic super markets…. From that time on, things got not better regarding the CD drive quality – it got worse – and today we have to accept, that in most modern CD players we will find just crap, which has to do the sensitive job of reading data from a digital media!

What really changed during all this years is maybe the quality of the DA converters – in the 80ties more that 16 bit resolution was seldom seen – and at the end of the ladder DAC period, 20bit performance was the best we could achieve with this technology. However – if we do not get the data from the media with the highest possible integrity and precision – if our source is not of the highest quality – all which comes in the signal chain after that stage is more or less questionable.

Restauration of a masterpiece:

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The CDM 1 Pro drive used in one of the most well regarded CD players during those years, the Marantz CD94 (and also the MK II version of this player) will have some problems because of its long period of usage, we have to care about. Most of the units which are offered as defective, do not have any trouble with the laser diode – they all share one design problem, which we have to deal with. This design “problem” addresses the bearing of the rotary CD platter. This bearing is constructed as a plain bearing – a spindle is placed on a special plastic disc – the plastic is of such a kind, that the spindle do not need any excessive lubrication. Over the years this spindle works now its way into the plastic platter – there will be at any CDM1 pro a more or less deep groove in this plastic platter of the main drive bearing.

If the groove is cut very deeply, the distance between the CD surface and the movable laser diode is at some point too large – so the laser unit can not precisely focus anymore. The player will give us some error message – and most of the users think – the laser diode is worn out – but in most of the cases it is just a mechanical bearing problem . To solve that, we have to adjust the platter hight to a point were we compensate for the groove. This is manageable with a little bit of technical skills and a service manual developed for the specific player and its Philips drive mechanism. If we adjust the spindle height to a level, were the two axis element of our laser mechanism is positioned in its neutral level again – we are done. Of course one day the plastic disc of the bearing will be completely worn out – and there is no chance to get a replacement part as far as I know – but I can assure you – the mechanism will work for another 15 years from now on – if we do not use the player as a burn in device – playing in continuously repeat mode for weeks or months;:)) In the service manual we will find a certain voltage and the points were we can measure it to adjust the platter hight – for that procedure a perfectly flat CD has to be used with some test signals on it (CD/R made by yourself). All in all, if you know how the procedere works, it is a job done in 20minutes. If you do a good cleaning (highly recommended), the whole work will need a little bit longer.

Recap:

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Another thing we have to deal with are all the electrolytics used in the player – not only in the drive compartment – I mean all the electrolytics, this is a job done with a lot of care and some patience. Today we have some great opportunities with modern designed caps. The SANYO OSCON electrolytics have a very temperature independent behaviour which is a very good thing with all the digital circuits and the drive mechanism. At other stages we can decide to use caps which we like because we think they give the unit a specific sound (Black Gates, Elna…) – and of  course we have the amazing Panasonic FC cabs, which is a strong recommendation for the power supply decoupling.

Sound experience:

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After the complete recap, we will be stunned, how such an old device will sound. The Marantz CD94 has maybe one of the smoothest treble performances of all CD players I know of – it is the opposite of what we will find in most modern players – the treble has a sort of creamy gestalt! This could be a good thing – because of 100 CD´s 98 are mastered with a very hot or aggressive treble – a circumstance which seems to characterise the digital sound, but which is more or less also a problem of the software itself. To explain this more in depth, I have to dig a little bit deeper – we have to talk about production techniques in the recording stage, mixing and mastering process. If you compare a modern digital workstation as AVID Pro Tool against a 24  Track 2″ tape recorder there is a huge difference – not only in the native sound of both units – more so in the style you are able to use them. With an analog recorder we have a certain limit with the frequency extremes. We cannot put the same amount of level on the tape in the extreme bass region as also in the treble region compared to the whole midband. If we do so – the tape machine has a surprise for us – or better two of them – noise or distortion. Lets say for a moment we want to produce a Hi Hat – and we want to have a sound with the highest amount of shimmer we can afford, there is a special technique to reach that. If we would put some EQ on the Hi Hat off the tape – after we already recorded that signal, we will boost tape hiss…. – if we put all the EQ to the Hi Hat before we record it – we will be punished with less gain possible to put on the tape – otherwise the signal will be distorted – and the result will be distortion or again tape hiss. So a mixture of both techniques is the goal – a little bit emphasis befor the signal hits the tape – and a little bit in the mix, were the signal comes off the tape. The keyword here is LITTLE!. In the digital world there is not such a limit…I am technically able to put 12db boost on a Hi Hat at about 12Khz – and there is no other punishment as my bleeding ears. Which brings me to the essence of that little example….if we engineers have no technical limits, it is up to us to decide what sounds good and what sounds bad. And with too much freedom, we will face a great risk to overdue it….In other words the analogue tape recorder is one of the biggest teachers for us recording engineers in the control room. Their limits give us a sort of certainty, which we all lost with the digital age! If you are sitting 10 hours or more behind the console, you loose the ability to judge the sound – but in the analogue domain we had some security implemented into the whole system, with digital everything is possible. And this is in my opinion one of the reasons, why with the upcoming digital technologie, we miss more and more a sort of natural sound – because all is possible and often some more treble in the mix seems to be more exciting….

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Now lets talk about the relationship between the producer, the artist and the recording engineer. It is a customer relationship – the producer wants a sound which competes with an international standard, the band wants a sound which is impressive and supports the idea of the song. Later on the mixing engineer will do the final work on a multi track session, often with more than 80 audio tracks implemented into the mix. Again the band and the producer wants to have the nearly finished product to be better than the reference recordings played back and forth during the mixing process. It has to be loud, powerful and impressive. So the mixing engineer will put a good amount of compression to the mix, as also a lot of EQ to make 80 tracks compatible to work with the basic idea of the song (a disaster!!!). Later on in the production process, the song hits a mastering studio – and again we have a customer relationship – the mastering engineer must bring the mix to a higher level – it is not “en vogue” to master the stuff in a natural way – it has to be louder than other comparable productions, it has to compete with the loudest tracks broadcasted at the radio. If the mastering engineer switches the mix file against the mastered version, all listeners in the mastering studio wanted to have this magic thrill – “Oh my gosh…..this sounds sooooo impressive”.

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At the end of that story we will have some music mastered on the CD which has at best 8db dynamic and we will face a frequency spectrum which boosts the extremes – a lot of shimmer, plenty of bass and a down shaped mid frequency spectrum – some tricks at the Flatcher/Munson frequencies and finished is another song which works perfectly in a car stereo system while driving on a highway at high speed – but listened to a good High End stereo system, we get bleeding ears – the music is boring – because no dynamic shades are anymore detectable – and we think – “Fuck digital”….but it is not the digital technology itself – it is the way we work with all the possibilities. If you have a chance to listen to Radiohead “In Rainbows” (for example) on CD, you will hear that it is possible to achieve something great, something outstanding even pressed on a CD, there is nearly no difference between the vinyl edition and the CD – and yes this album was recorded with an analogue tape machine…

Using the CD 94 as a dedicated drive:

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Coming back to the drive mechanism of the Marantz CD94 it is obvious, that this old machine will be a very good CD drive, maybe one of the best regardless of its price. If you want to skip the legendary DA converter implemented in this player – developed around one, if not the best 16bit ladder DAC the Philips TDA 1541chip set – you are in for a big surprise. But before “happy listening” we have to deal with the digital SPDIF (Sony – Philips – Digital – InterFace) interface which the engineers at Marantz implemented in this player to be able to communicate with external DA converters. You will detect a RCA jack at the back of the player – a thing, which most of the CD players have in common, regarding a SPDIF digital output. But this “standard” is wrong – completely wrong – because the SPDIF technology wants to “see” a proper 75 Ohm wave impedance. No RCA jack can deliver the proper specs implied in that technical standard – so we have to change the RCA connection to a proper BNC socket. And if we do that, we have to dig a little bit deeper. The Marantz CD 94 in it´s standard original configuration, gets its SPDIF signal from the Philips SAA 7220 digital Filter chip. The SPDIF signal is carried with the corresponding conductor path on the right hand side (mounted at the side of the chassis) daughter board and is further distributed by some connectors and cheap cabeling. So it is a good idea to grab the signal directly from the 7220 and use a dedicated 75 Ohm data-path together with a small circuit board, which brings the signal to the correct SPDIF specs – +/-0,5V and 75 Ohm wave impedance. Finally we feed the signal in our BNC connector and achieved a perfect SPDIF interface.

More modding:

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If you have tasted some blood now – there is even more, you can modify to reach the best performance – even if you just use the Marantz 94 as a dedicated CD drive. The Philips SAA 7220 is the biggest problem in the whole surrounding of the TDA 1541 DA converter and its signal flow. The reason for this is the HF dirt this chip delivers into the circuits of the whole player – this is more important if you use the player as a full function CD player – but also of some interests if you use just the drive mechanism. The Marantz CD94 was built at a much bigger budget, than one might think – but at some stage Philips/Marantz hat to cut down costs, because they wanted te player to be placed at the lower end of the High End player segment. At some parts of the player Marantz decided to drop the best solutions which were technical possible. One of this cut down areas is the power supply as also the delivery of the voltages to the different sections of that player.

First of all, the Marantz has just one power supply implemented – there is no seperation between digital circuits and analogue sections, as we will find them in Accuphase CD players of the same aera  (they were of course much more expensive). Accuphase used from the beginning of their CD player development on, always two separated power supplies, which facilitates them to isolate the digital path completely from the analogue path. Marantz opted for just one power tranformer / power supply. Why do we not modify an Accuphase player than??? – Because Accuphase used a Sony drive mechanism in those years and there is no hope to get any spare part for them anymore – and if we want to buy another player as a donor – the whole story would be very expensive – and last but not least – as good as the Sony drive mechanisms were, they found their master in the Philips CDM1 pro.

So we have to deal with the power distribution inside the Marantz CD 94. Our goal is to isolate as much as possible the SAA7220 from the rest of the player – to achieve that, we have to construct a dedicated rail only used by this chip. And if you are dealing with such an idea – built more than that single voltage regulator – because I know, that after reading Part II of this article, were I will dig deeper into the DA converter of this machine, you will use the Marantz not only as a very, very good CD drive…..;-)))

The original voltage regulators are placed at the heatsink, you will find on any TDA 1541 player, be it a Marantz, a Philips, Rotel, Naim and so on…. Now you know, why these players all share the same strange heat sink at the rear side of their chassis. The original player uses 3 regulators with this heat sink together – and we put another three into this machine. This gives us enough flexibility to modify also the analogue section of this player – but more important to give the SAA7229 beast its own rail with discrete voltage regulation.

The marriage with a high performance DA converter:

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If you use the Marantz CD 94 drive with an outboard DA converter using our modified SPDIF interface, you also have to get a proper SPDIF cable. It is not recommended to use a normal NF cable, which you normally use between your preamplifier and power amplifier – because a dedicated SPDIF cable has to be made with the 75 Ohm standard in mind. A very, very good choice is one of Chris Somovigos digital cables, he developed exactly for that purpose. In other words – this is one of the best options I know of. Be it a Stereovox, Stereolab or Black Cat 75 Ohm SPDIF cable – all are super performers – and you do not have to spent more money to achieve a better quality – these cables are of the highest class!

Now you have the choice to choose a DA converter you may have on top of your wish list. You can buy the newest and hottest stuff available to get the best of two worlds – the best drive mechanism ever made AND a ultra modern High End DA converter. One of the most exciting combinations will be a DCS Paganini if your speakers and the whole system is very neutral and not overly analytic. This combination is soooo good, that you will forget to play vinyl records for a long period of time. The combination is much better, than the integrated DCS Puccini CD/SACD player. The Marantz – do not ask me why, has a certain smooth sound, even if you use just the drive mechanism of the complete player. The sound of the drive is so grain free and elaborated at the treble spectrum – it is amazing – together with a very, very high resolution converter as the DCS Paganini is, you will get something which is hard to describe. If I have to characterise this specific digital sound to a moving coil cartridge, I would choose the Lyra Etna SL as an analogue opponent. A frightening resolution paired with a smoothness (used in a proper tonearm with a high quality SUT) and velvety gesture is apparent, a pinpoint accuracy which let you breathe the atmosphere of the recording event – fantastic!

If you use a pair of the legendary BBC LS3/5a monitors, the combination of the Marantz CD 94 drive with a DCS Paganini is not the best option. The LS3/5a has a slight treble rise – it is in that discipline the opposite to a well placed and integrated Quad ESL 57, which acts a little bit defensive at the highest frequency spectrum.  With the use of the BBC monitors a non oversampling tube DAC would be my first choice. And one of the finest options with a lot less money to spent as with the super expensive DCS stuff, will be the German manufacturer Acousticplan. The Digi Master  Tube DA – converter is a hell of a machine!!! If i should compare this combination with the analogue world of cartridges and turntables – I would go for the gestalt of a very nice Koetsu Rosewood Signature cart. A slightly recessed treble paired with a good punchy bass and the ability to layer the recorded space in a more integrated style. This combination is not analytic, it is about the tone, the beauty of the midband and the wholeness of the musical performance.

Stay tuned – part II of the Marantz CD 94 will come soon.

E. Strauss