Adcom GDA-700 DAC - Updating to modern parts, advice!

[lantian]

Very nice work. Happy to see others deciding to hot rod their equipment as well.
If in future you decide that you want a step up from parts you already got, then would recommend takman rey resistors.
As for cap if you want the best you can get then electrolytes would be audio note kasei, films would use amtrans amch or amcg.
And get rid of all those ceramic capacitors if possible, they have no business being in audio circuits.

 

[billyGnoud]

Hi Nayyte!!! Amazing work!!! How were you able to desolder the opamps? I have gone through two adcom gda 600 dacs, and both dacs opamp chips somehow have pin 8 expoxied to the pcb… I literally had to drill though the solder pad in order to install new opamps…. Did your gda 700 have opamps soldered in a way that it is almost impossible to desolder?

 

[Nayyte]

My gda-700 didn't have the sockets glued, just solder. It was easy to remove once I got it all heated. The most annoying part of the whole build was all the trial and error with the opamp rolling. Realizing in the end that it's crucial that the opamps are as close to the board as possible otherwise they made the sound very out of wack. I don't have the DAC anymore but if I wanted to own a HDCD DAC again, I would buy another used one in a heartbeat. A differential design DAC with dual pcm1702 chips holds up extremely well to modern options and I still believe that they easily surpass the new ess and akm chips. In the end it's pretty annoying not having USB and the clock management being irreplaceable is unfortunate.

 

[billyGnoud]

My gda-700 didn't have the sockets glued, just solder. It was easy to remove once I got it all heated. The most annoying part of the whole build was all the trial and error with the opamp rolling. Realizing in the end that it's crucial that the opamps are as close to the board as possible otherwise they made the sound very out of wack. I don't have the DAC anymore but if I wanted to own a HDCD DAC again, I would buy another used one in a heartbeat. A differential design DAC with dual pcm1702 chips holds up extremely well to modern options and I still believe that they easily surpass the new ess and akm chips. In the end it's pretty annoying not having USB and the clock management being irreplaceable is unfortunate.

Would you consider using a DDC to the adcom gda 700 ? That should allow usb and clocks

 

[Nayyte]

I would if I had one. I don't really see them need currently in my setup. The biggest weakness of the gda-700 is the digital input section. It was very barebones.

 

[billyGnoud]

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[Nayyte]

PSA if anyone from the interent is here looking to do a similar mod. DO NOT MESS WITH THE DIGITAL SECTION BYPASS/FILTER CAPS.

The stock parts in the digital section are just fine, and after I replaced them the pretty sound of the 1702 turned sterile for the worse.

I was very happy with the sound after all the mods to the PSU, addig new opamps, and all the tall caps on the digital board. Don't mess with the digital section too much.

The mods listed in post #11 are the perfect amount. The additional mods posted later messed with the sound too much.

PPS: keep the opamps as close to the board as possible, the extra risers seen in photos are unnecessary.