HELP! Need opinions for upgrading to Benchmark DAC1 HELP!

Quote:

Originally Posted by Alain3x 

My current D/A converter is an asus xonar essence stx(Sound card). I would like to upgrade to a Benchmark DAC1. It would then go throught a little dot mk3 (upgraded tubes m8161 &m8100) with a apir of AKG K702. My question is: Should I keep my current D/A or should I invest 600$ for a Benchmark DAC1?

Thank you,

Alain.Galarneau

$600 for a DAC1? Is it second hand? You will experience better more defined soundstage, more detail and faster transients by upgrading.

If you haven't already, you could upgrade your Asus Xonar Essence soundcard. But you'd need some soldering/desoldering skills of small surface mount components.

Here's how I hacked my Essence ST - I believe the STX is the same DAC hardware, just a different bus interface.

The ICs ZU14- ZU16 need to be rolled - fortunately these are socketed (btw these are beneath the snazzy screen, so that should be removed first). ZU14,16 are exchanged for LM6172 and ZU15 becomes an NE5532. I must admit I haven't tried other options for ZU15 just that I found 5532 sounded better than the supplied 4562. ZU14 & 16 though definitely sound best with LM6172 out of a number of options I tried.

The other part of the mod requires some soldering skills. The caps adjacent to pins1 and 7 of ZU14 &16 need changing for 10pF, 0805 footprint. That's 4 caps in total to swap over from the existing ones (which I believe to be 2200pF though I destroyed mine in the desoldering process so wasn't able to check this).

Subjectively this mod gives greater depth to the soundstage and seems to resolve lower-level details better. Total cost was about $3, for the money its excellent value

Quote:

Originally Posted by Sapientiam 

 

 

Here's how I hacked my Essence ST - I believe the STX is the same DAC hardware, just a different bus interface.

 

The ICs ZU14- ZU16 need to be rolled - fortunately these are socketed (btw these are beneath the snazzy screen, so that should be removed first). ZU14,16 are exchanged for LM6172 and ZU15 becomes an NE5532. I must admit I haven't tried other options for ZU15 just that I found 5532 sounded better than the supplied 4562. ZU14 & 16 though definitely sound best with LM6172 out of a number of options I tried.

 

The other part of the mod requires some soldering skills. The caps adjacent to pins1 and 7 of ZU14 &16 need changing for 10pF, 0805 footprint. That's 4 caps in total to swap over from the existing ones (which I believe to be 2200pF though I destroyed mine in the desoldering process so wasn't able to check this).

Yes, the orig. value (per the PCM1792 datasheet) seems to be 2200pF. 

That's a delicate PCB to hand solder. De-soldering the old SMD components can be tough. You can save yourself the trouble of soldering on those replacement caps by simply soldering them to the top of the pins (legs) of the op-amp IC. For LM6172 (or other), that feedback cap is from inverting input to it corresponding output:

Pin 1 - Pin 2 and Pin 6 - Pin 7 on BOTH op-amps.

There is an added potential bennie here: electrical signal path is as short as possible (on the DIP version, solder the cap as close to the IC body as possible).

This also works well for other cap bypassing/decoupling, tho it may not look as pretty.

http://www.national.com/ds/LM/LM6172.pdf

Yep, that's a good idea - soldering the feedback cap across the pins. Means rolling opamps automatically includes the correct feedback cap for the chip. Nice.