Rec. output stage mods- Sony DAS-702es NOS dac

homemade · 9th July 2005, 08:14 PM

Just acquired a most interesting Sony DAS-702es d/a converter. 30+lbs. Extreme build quailtiy. ELNA Cerefine/ film capacitors throughout. The dac chips(2) are #cx20017. From the info I have gathered , these are 16 bit, voltage out , with NO oversampling , NO digital filter. Just a LPF with 3 TI 5532 opamps per side. The amazing thing is how GOOD this thing sounds. It bests my Scott Nixon (1543)and Paradise(1545) battery powered dacs in detail and bass. It is also more extended(but not bright!). Just as a reference , I'm using gainclone amps with my open baffle speakers , with ESG-1 ribbons on top. Linkwitz OB subs below 150hz. My transport is an NEC cd-rom drive(several types). I remember all the talk years ago that the first gen of players had a 'glare' to them , but certainly not here. Very enlightening. Anyhow , to my request. Can anyone tell me if I can take the signal directly from the dac chips? Or should I use other opamps(which do you rec.) . I would prefer to do this without to much surgery. All help is much appreciated.

homemade · 9th July 2005, 08:15 PM

pic of Low Pass Filter section

homemade · 11th July 2005, 07:28 PM

build date 1983

ok · 12th July 2005, 08:00 AM

CX20017 not usual DAC. It is a "dual slope" DAC. Two first OP after CX is a part of DAC in usual understanding.

jimbobjim82 · 17th March 2009, 01:02 PM

Sorry to bump such an old thread but I've just bought one of these myself and am keen to know what the blue switch banks do (see post 2 for pic). Does anyone know?

Flicking them does alter the sound but I don't know what each individual one does.

Cheers.

jimbobjim82 · 19th March 2009, 06:31 PM

Anyone?

tubert · 9th April 2009, 11:40 PM

Q1. Can anyone tell me if I can take the signal directly from the dac chips? Or should I use other opamps(which do you rec.) . I would prefer to do this without to much surgery. All help is much appreciated.

A1. I think not. It looks to me like this dac sends 16 individual voltages to the sample/hold circuitry and even if it doesn't, taking a 'tap' from the dac would require a massive overhaul of the main circuit board.

The reason this unit sounds so good is in fact, because of the build quality, not the technology it uses.

Q2. Sorry to bump such an old thread but I've just bought one of these myself and am keen to know what the blue switch banks do (see post 2 for pic). Does anyone know?

Flicking them does alter the sound but I don't know what each individual one does.

A2. These switches contol the gain of each chanel. It's just a resistor network with different values for each "flick".

Why did a noob join this board? I've had one of these units since 1990 and 6 months ago one chanel went bonkers. It just started making the worse noise I've ever heard and it's obviously not an analog issue. You can still buy the serial data converter but I suspect the dac and as you can see from the pics above, you can't read the part number.

So now I'm off to find a SONY CX20017 dac. Thanks for the info on the chip and I hope my advise helps you guys.

}---:)

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11th July 2005, 07:28 PM	#3
homemade diyAudio Member Join Date: Jul 2004 Location: us	build date 1983

12th July 2005, 08:00 AM	#4
ok diyAudio Member Join Date: Nov 2004 Location: St.Petersburg	CX20017 not usual DAC. It is a "dual slope" DAC. Two first OP after CX is a part of DAC in usual understanding.

17th March 2009, 01:02 PM	#5
jimbobjim82 diyAudio Member Join Date: Feb 2009	Sorry to bump such an old thread but I've just bought one of these myself and am keen to know what the blue switch banks do (see post 2 for pic). Does anyone know? Flicking them does alter the sound but I don't know what each individual one does. Cheers.

19th March 2009, 06:31 PM	#6
jimbobjim82 diyAudio Member Join Date: Feb 2009	Anyone?

9th April 2009, 11:40 PM	#7
tubert diyAudio Member Join Date: Apr 2009	Q1. Can anyone tell me if I can take the signal directly from the dac chips? Or should I use other opamps(which do you rec.) . I would prefer to do this without to much surgery. All help is much appreciated. A1. I think not. It looks to me like this dac sends 16 individual voltages to the sample/hold circuitry and even if it doesn't, taking a 'tap' from the dac would require a massive overhaul of the main circuit board. The reason this unit sounds so good is in fact, because of the build quality, not the technology it uses. Q2. Sorry to bump such an old thread but I've just bought one of these myself and am keen to know what the blue switch banks do (see post 2 for pic). Does anyone know? Flicking them does alter the sound but I don't know what each individual one does. A2. These switches contol the gain of each chanel. It's just a resistor network with different values for each "flick". Why did a noob join this board? I've had one of these units since 1990 and 6 months ago one chanel went bonkers. It just started making the worse noise I've ever heard and it's obviously not an analog issue. You can still buy the serial data converter but I suspect the dac and as you can see from the pics above, you can't read the part number. So now I'm off to find a SONY CX20017 dac. Thanks for the info on the chip and I hope my advise helps you guys. }---:)

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