Review : AUDINST HUD-MX1 DAC/amp - a promising newcomer (compared to Audio-gd FUN, AMB Gamma2) - Page 3

AD797brz feels like a nice match and improvement and I have no serious intent of exploring other options.
LT1028acn8 is highly regarded as well, and reputed for it's warm signature. That may be an option. I won't go into it as it's rather pricey (2 x 14$ + BD adapter + shipping) and have no other use for it.

Next week my Audio-gd Roc is supposed to arrive and I'll probably sell the Matrix M-stage (which is the only other device I have with interchangeable opamps).
So no more opamp rolling for me.

I'm using a TREAD PSU, which I've built myself -->> Tangent Regulator, Adjustable, plus Diode bridge
Warren (aka Tangent) sells it as a kit for a mere 17$ - Tangent's Parts Shop
You can buy also Browndog adapters from him as well (which I recommend).

You'll need to add a few things:
- heatsink for the LM317 regulator (not included in the kit). You can buy one from any electronics shop.
- 1Kohm carbon film resistor for R2 (the kit comes with a 2.2 Kohm resistor). The original kit is designed to output between ~ 22 and 30V. Using a 1Kohm R2 instead of the original 2.2Kohm, you can adjust between 12V and 22V.
- a transformer. I use a wallwart transformer, which feeds the TREAD with 18V DC. Even a cheap one will do.

Tangent's page is very well thought out and provides all necessary info for putting together the TREAD.

Other DIY PSUs :
- AMB Labs Sigma11 -excellent, but more complex & pricey, bit of an overkill for Audinst: The σ11 Regulated Power Supply
- AMB Labs Sigma25 - simple, cost effective design: The σ25 Regulated Power Supply
- Velleman K1823 , a more inferior design but still pretty good - K18231A Power Supply : Miscellaneous Kits : Maplin

I don't know any commercial linear regulated PSUs with good performance & low cost.

I haven't listened to the Pico DAC, so can't help you with a comparison.

Currawong says PICO is similar to Audio-gd FUN, which I know pretty well.
Other people say that PICO resembles quite a bit the Gamma2 DAC, which I own.
In either case Audinst would be considered inferior, but not far away.

Unfortunately my Gamma2 has died on me (probably because a cold joint) so I cannot finish the scheduled comparison this week.
I won't be able to get it back up and running sonner than the weekend.
I'll update the review some time after that.

I did however spend two evenings comparing the two, and what I've listened so far favors the Gamma2 by some margin, depending on power.

Gamma2 has a smoother and more refined character which indicates a more mature sounding DAC than Audinst (probably because of it's upsampling and ASRC circuit). Gamma2 is improving the already very good HUD-MX1 in just about every department.
Sound signature is slightly warmer and fuller on Gamma-2. Also more engaging (timing and rhythm is very nicely executed).
Overall Gamma-2 feels and sounds like an expensive source, while Audinst like a very good budget source (honest, plenty resolute, but not as refined)


Differences aren't big and the PSU has actually the last word here:

- Gamma2 fed by TREAD PSU is superior in just about anything to Audinst fed by USB or wallwart. Both fed by TREAD the gap is not as large and Audinst can hold its' own.

- Gamma2 fed by USB is hardly different or superior to Audinst fed by the TREAD.

- Both fed by USB, there are a few differences, but nowhere near as big as discrete.
I think feeding the Gamma2 by USB is a crime.
It's such a good sounding DAC, but it doesn't show it's full colors and bloom until fed by clean power.

I've already ranted about this very issue. Check my previous posts.
Just to be clear:
Audinst plays significantly better when fed by a quality linear regulated PSU (such as TREAD, not the stock wallwart), compared to USB.

They pair very well. Both are pretty neutral units and somewhat complementary (Audinst - cooler, M-stage-warmer, fuller) and cannot see any reason of mismatching.

TREAD is the best documented of all for a beginner. So that's my first and strongest recommendation.
Tangent also has lots and lots of tutorials starting with basics (electronics and even soldering) and going into quite complex matters. I like his articles very much as they are exquisitely comprehensible for a wide range of people with different background, experience, age, etc.

I don't think Pico rates so low. From what I've read about it it seems the closest to the FUN.
Would love to compare it to Audinst, but don't know anyone near me owning a Pico.

I'd rate the 4 units sonically in the same order as their prices suggest.
Just by an informed guess (but stil a guess!) - Pico somewhere between Audinst and FUN, although God knows closer to which.

I would rate uDAC the lowest as it is so clearly outperformed, outgunned and outmaneuvered by the Audinst.
uDAC is a very nice entry-level DAC that scores high for an equilibrium between musicality and performance. On SQ alone it's not that different from a good soundcard, but it does present a more musical/authentic kind of presentation that makes me appreciate uDAC higher than soundcards.

The other three DAC/amps are superior designs and more serious performers so I wouldn't put uDAC so close to them.