My tweak story began when I bought a Cayin CDT-17A CDP on February 2005. I was a little disappointed for the price. Nevertheless, I could hear its potential. So I decided to improve it by very easy ways : replacing existing tubes 6922EH and IC-OPA -6 OPA604AP, 4 AD827JN- by better ones according to the PCM1792 scheme, one per channel. I found the tubes : the great Mullard grey plates E188CC among excellent CCa Siemens and RCA E88CC/E188CC…

As I didn’t want to replace at first the « I/V conversion » section’s ones under red heatsinks –Dual AD827-, I set my heart on single OPA in  « single-ended » section –two OPA604AP- and  in « Differential Section » -four OPA604AP-. Some tests later, I kept AD843JNZ and OPA627BP among OPA604/OPA134/AD845/AD847/OPA627AP/OPA227NE5534
But I was not as satisfied as I should : I found Vecteur L4.2 and Jolida JD-100S –without any IC-OPA in use for signal path- better than my Cayin. I was sure that the problem came from IC-OPA because there still were « coloration » whenever I changed from one to another.

So I looked for best solutions without finding any until I red some experiments about Burson team’s products…  I didn’t really believed in their explanations, so I passed my way. One month later, a friend of mine –Thibault Siezien from Belgium- talked me again about it. He though it could be a good solution for my CDP since these OPA were discret and not Integrated circuit made. I have a lot of place to work in the CDP, so I decided, thanks to him, to buy 4 Burson Discret single OPA to use in « differential section » as I only use it in XLR way . I noticed that my Cayin was so far better on Symetric output than on Asymetric output since the scheme is a real symetric one.

After replacing my OPA627BP/AD843JNZ by Burson Discret OPA on that section, I undestood at a glance I was finding what I have searched for so many months. The difference was so amazing that I couldn’t believe I had the same CDP in front of me : The soundstage became exceptionnal in « wide » and « deep » aspects. I could almost see the stage with protagonists on it ! The music instruments and voices’ 3D positions are accurate and precise.
The piano sounds like a piano! Actually, the piano is a very difficult music instrument to be reproduced. With Burson Discret OPA in « differential section » the played notes get body impacts and feel « full ». With OPA627BP, the sounstage is very nice more deep than wide but the notes feel « half »  played and the bass, where have the bass gone ? With OPA134AP/OPA604AP, the music feels « slow », not precise since the soundstage is very « musical ». With AD843JNZ, the performance is acurate but the « remanence » disappears and the « musical » effects and atmosphere with it. Besides, the midrange and sounstage are not so good.

But Burson Discret OPA are « quick » and the attacks of the notes make feel the music instantaneous, like a snapshot. It’s more neutral and realistic. You can feel physically the piano, it comes true. The tones and snares are marvellous because they seems to be real and true. Dynamic is exceptionnal : the high are « aerial » without becoming « harsh » neither agressive, the bass are « decent » and « honest » without being « boomies », the midrange is « warm » without being « caricatured » nor « grotesque ». Details contribute to catch the mood of the audience around so well that I can clearly listen to the record machine’s motor  on some CD!

I hope my experiment/experience paper shall be making the listeners and readers up. People nowadays choose wine by their type while they should choose it by « terroir » ! More than that, when you spend a lot of money for a good bootle of wine, Burson Team nearly offers it to you and Nirvana becomes true! It is not because you have the best parts in your electronics that you can make a fantastic one. Burson Team understood it and made a cleaver cocktail enough to catch the « musical reproduction », thanks to inanimate electronics, to make it alive. Burson is, to some extent,  the « coin perdu » of the HiFi : tests and tasting are the secrets of success ! « Longue vie » to the Australian team…

NB : to profit fully of the Burson Parts, I recommend over hundred hours of « burn-in »…                                                

Some « cut-off » of the listened test CD :

–      Stefano Bollani, Smat-Smat (Label bleu) : « la vita intensa »
–      The Bad Plus, These Are The Vistas  (Sony): « Keep The Bugs Off Your Glass And The Bears Off Your Ass »
–      Bojan Z Trio, Transpacifik (label Bleu) : « The Joker »
–      Orchestre de Contrebasses, Ch. Gentet (Musica Guild) : « Bass, Bass, Bass, Bass & Bass »
–      Rachmaninov/Rachmaninoff , Concerto N°3 pour piano, Horowitz/Ormandy (RCA) : « Allegro ma non tanto »
–      Archie Shepp Quartet, True Ballads, Gold 24K : « the thrill is gone »
–      John Lee Hooker, Chill Out (Virgin Records) : « Annie Mae »
–      Sara K. & Chris Jones, Are We There Yet (Stockfisch) : « (would You) Break My Heart. »
–      Helen Merrill-Gordon Beck , No Tears No Goodbyes (Universal Music): « When I Look In Your Eyes »
–      Lisa Ekdahl-Peter Nordahl Trio, Back to Earth (RCAVictor) : « it Had To Be You »

Cayin CDT-17A Tweak :
Comparaison of Cayin CDT-17A of Teiki Arii with OPA2134AP in « I/V Conversion » section to other CDP, by Boonjik :

Tweakage de la Cayin CDT-17A diapason d’or 2005

par teiki arii » 05 Avr 2005 18:16
Salut à vous tous détenteurs de Cayin CDT-17A!!! Place au tweakage…

Ma Cayin CDT-17A d’origine:
– MODE I (full OPA627BP, 4 x Condos MUNDORF 3.3uF 1200VDC SILVER OIL en XLR, ALIMENTATION CRC, MICA argentés NOS):
– MODE ULTIMA (MOD I + AOP discrets, Super Clock, Low ESR):
CAYIN CDT-17A RCA Full-PCM de Trencito en configuration 6 x Burson Single Discret OPA avec la Burson Clock:
CAYIN CDT-17A RCA Full-PCM de Zert en configuration 6 x Burson Single Discret OPA avec la Burson Clock:
Compte-rendus indépendants sur les E88CC/E188CC/7308/6922 compatibles avec la Cayin CDT-17A:
caractéristiques de la Cayin CDT-17A:

– uses American BB Corporation newest promoted 24bit/192kHz electric current output DAC PCM1792 carries on the D/A transformation.
– the first section true entire balance design CD broadcast machine, namely uses 2 piece of PCM1792 chip alone signal processes for two sound tracks distinctions.
– the complete vacuum tube outputs, the balance and the non- balance audio frequency output circuits uses Russia produces the 6922EH vacuum tube.
– the complete digital signal output, includes the optical fiber outputs, coaxial outputs, the balance (AES/EBU) outputs.
– lowly passes the filter circuit uses the American BB Corporation sound special-purpose transports puts OPA604.
– uses PHILIPS the CD7II numeral servosystem.
– Analog and the digital circuit separately uses the independent power transformer and the rectification constant voltage system supplies power.
– the use specially lowly leaks the magnetism, the highly effective rate ring-like power transformer for this machine development.
– the VFD lattice display monitor, the aluminum and the stainless steel combination kneading board, the outward appearance modelling luxurious is natural, is advantageous for matches with the different brand sound equipment.
– uses the 2mm steel plate purifies the engine case, the rigidity is good, machine the core uses entire seal dustproof structure processing.

* Output level: 2.3v±0.5dB
* Frequency response: 20Hz ~ 20kHz±0.5dB
* The distortion adds the noise: < -70dB
* Signal to noise ratio: 92dB
* Dynamirange: 120dB
* Crosstalk (fundamental wave 1kHz): -100dB
* Digital output: Conforms to the IEC958 standard
* The volume (long * width * high): 40mm×390mm×130mm
* Weight: 16kg
* Power consumption: 40W

The design of the application circuit is very important in order to actually realize the high S/N ratio of which the PCM1792 is capable. This is because noise and distortion that are generated in an application circuit are not negligible. In the circuit of Figure 36, the output level is 2 V rms and 127 dB S/N is achieved. The circuit of Figure 37 can realize the highest performance. In this case the output level is set to 4.5 V rms and 129dB S/N is achieved (stereo mode). In monaural mode, if the output of the L-channel and R-channel is used as a balanced output, 132 dB S/N is achieved (see Figure 39). Figure 38 shows a circuit for the DSD mode, which is a 4th-order LPF in order to reduce the out-of-band noise.

– I/V Section
The current of the PCM1792 on each of the output pins (IOUTL+, IOUTL–, IOUTR+, IOUTR–) is 7.8 mA p-p at 0 dB (full scale). The voltage output level of the I/V converter (Vi) is given by following equation: Vi = 7.8 mA p?p × Rf (Rf : feedback resistance of I/V converter) An NE5534 op amp is recommended for the I/V circuit to obtain the specified performance. Dynamic performance such as the gain bandwidth, settling time, and slew rate of the op amp affects the audio dynamic performance of the I/V section.

– Differential Section
The PCM1792 voltage outputs are followed by differential amplifier stages, which sum the differential signals for each channel, creating a single-ended I/V op-amp output. In addition, the differential amplifiers provide a low-pass filter function. The op amp recommended for the IV circuit is the NE5534, and the op amp recommended for the differential circuit is the Linear Technology LT1028, because its input noise is low.

liste des intéressés:
teiki arii.

liste des Op Amps candidats au remplacement des OPA604AP – Filter and RCA Op Amps -:
– monochips – échange standard -:
– Burson discret single OPA sûre
– OPA627 AP & BP sûre
– NE5534 sûre
– OPA227 sûre
– OPA134 sûre
– AD843 sûre
– AD845 sûre
– AD847 sûre
– LM6171 presque sûre
– AD797 presque sûre
– AD844 presque sûre
– OPA637 rejetée
– OPA228 rejetée

– dual chips nécessitant un “shunt” de l’une des deux – cf liens ci-dessous -:
– AD826/AD827 presque sûre
– OP275 sûre

– mono chips nécessitant un adaptateur SOIC8/DIP8 – cf liens ci-dessous -:
– AD825 sûre
– AD8610 sûre
– AD8065 presque sûre
– THS4631 presque sûre
– THS4031 presque sûre

Adaptateur d’une monochip SOIC8 pour faire une monochip DIP8 – original OPA604AP -, intéressant le RCA Op Amp – en position 1 – et les Filter Op Amps – en position 2 & 3 du schema B définitif de 00940 –

liste des Op Amps candidats au remplacement des dualchips AD827/NE5532 – I/V conversion Op Amps under red original heatsink -:

– NE5532 sûre
– OPA2134AP sûre
– AD826 sûre
– AD823 sûre
– AD827 sûre
– LM6172 sûre
– LM4562NA sûre
– Burson discret Dual OPA presque sûre
– Double OPA627 sur adaptateur DIP8 presque sûr
– THS4032 presque sûr, moyennant un adaptateur SOIC8/DIP8
– OPA2111 presque sûre
– AD828 presque sûr,
– AD8039 presque sûr, moyennant un adaptateur SOIC8/DIP8
– AD8066 presque sûr, moyennant un adaptateur SOIC8/DIP8
– AD8620 presque sûr, moyennant un adaptateur SOIC8/DIP8
– OPA2227 presque sûr, DIP8 natif
– EL2244 presque sûr, moyennant un adaptateur SOIC8/DIP8
– THS4631 presque sûr, moyennant un adaptateur DOUBLESOIC8/DIP8

Schema et numérotation B selon 00940 de la Cayin CDT-17A:

– monochip RCA Op Amp n°1: désymétrisation de XLR vers RCA – donc absent par la sortie XLR -.
– monochips Filter Op Amps n°2 et n°3: pour le filtrage des pôles + et -.
– dualchips I/V conversion Op Amps n°4 et n°5: pour la conversion I/V.