I already start to make some mods in my AA Dac. I’ve change some caps to better ones from Panasonic.
Meanwhile, I met a new friend online - in another forum - and he gave some tips for some really great mods mostly concerning the analog opamp output.
The AA has an Analog Devices AD746 opamp - rather old - and I will change it for a Burr Brown OPA2107AP with some “small” changes.

So here are some pix from part of the project:

From the back


From inside with some new Caps


Opamp AD746


The schematics for the new BB OPA2107 opamp

Awesome project.

I'll follow this closely.

Tanx Paul.
I'm not sure yet if i have to make another case for the mods i intent to do...Because as you see the AA case is too small and i have to do some quite a professional soldering in that opamp... Four caps and two resistors only in pin 4 ...
Also i will try to make another power supply. I'll put the schematics for the PS later on.

Looks like an interesting project. Please keep up the posts as you proceed. It would also be interesting to hear the results of some before-and-after listening if you can find someone with an unmodified unit that can be used for direct comparisons. Thanks for sharing.

Tanx rroobbcc.

Soon i'll ordered the components and start doing the mods i keep you guys posted.


The AA Power Supply project schematic

Suddently i remember that you can order a free sample from the guys at Texas Instruments : http://www.ti.com/ I'll ask them if they send me an opamp sample...

I have recap the rest of the 220uF eCaps this time with Nichicon Ultra-Low Impedance e.Caps, and again a small improvement in the lows and a better smooth highs freqs.

Since i can not find opamp 2107 anywhere i already ordered Burr Brown OPA2134 and National LM4562 to has the chance to find witch one suits better in the Alchemy dac.

Personally, i have great expectations concerning LM4562.

Meanwhile i also ordered the few components for the new power supply.
The project goes slow, but forward.

A step back...

I’d heard that it happens to others before, well yesterday it happens to me. I screw up a little segment of the AA pcb circuit board. Damned, Damned, Damned!!!
I was desoldering a cap, my youngest son made a small cut in he’s hand, I look at him to see what happened, than a look at the solder iron and I have part of the circuit on the iron… I felt like was kicking in the balls…
I have done hundreds of soldering and desolderings, and none of this happens before…
Of course I tried to solder again the small segment of the circuit, but it was all in vain…
I have my Power Supply concluded next week, – it’s been quite difficult to find a +15 -15 transformer, not to mention the opamps... - and now this…

Any tip from you guys will be very helpful.

ah, i hate when that happens (even though i've never worked on a circuit board before).

i wouldnt know the first thing about where to go from here, but maybe this will help?
http://www.circuitrework.com/guides/guides.shtml

Tanx Scott. Great link.

Well, i manage to repair the AA pcb circuit that was broken!

The pics speaks for themselves:

way to go Alvaro.

Outstanding job, Alvaro.

Many tanx guys.

It was not an easy thing to do...lots of patience and nerves of steel , other wise all the hours and work and money invested on this baby were all down the drain. Besides i have to drill a small hole 0,5 mm in the pcb to reach the broken link in the SAA chip dac.
Tanx God, everything turns out fine.

oh, that's such good news!

Remember my offer- if you ever catch a DTI or a second DAC here on american eBay or Audiogon, I'll gladly help broker the deal for you.

The DTIs have been going for around $125 before shipping, with only one going for just under $70 a day or two ago. I thought with the large amount of bids on it, it'd have sold higher.


I've seen a few Theta digital jitter reducers as well.


alvarro, have you had any issues with the Audio alchemy DAC humming? It'd be a low-level hum. Very minor. I'm trying to figure out if it's the unit people sometimes have issue with, or if it's the power supply?