Zero DAC power supply mods, an inquiry

[espressogeek]

A few weeks back I purchased a Zero DAC from China. While its not an elegant piece of kit it sounds decent running off a HagUSB I assembled. I was curious about the potential to be gained by upgrading the power supply components of this unit. Below is a run down of the vregs, some measurements and links to pictures.

1 - LM117T - 3.3v (10.6v in)
1 - LM117T - 5v (10.6v in)
1- LM7812 - 19.8v in, 11.8v out

1 - LM337T - 7.2v in, 6.2v out
1 - LM317T - 7v in, 1.2v out

HIGH RES PICTURE OF ZERO BOARD

I am interested in what improvements could be made to the DAC's vregs and related components. Most folks that mod these don't touch the vregs and instead just go for cap swaps and bypassing. I would like to take a more detailed approach including potential power supply mods and I/V upgrade/replacement.

I have been investigating shunt style regs for the 3.3v and 5v units. I do not see any reason replacing these with the shunt style units from TENT or others would not work. Any feedback regarding this would be appreciated.

Also I am a bit miffed as to what the LM7812 and LM3xx regulators are for. I checked the V+ and V- pins on the op amp in the output section and it reads 30v on the nose as do the op amps in the headphone amp section. I really don't care about the headphone section (I will be disconnecting the headphone board) and perhaps even the I/V as I will be replacing it in the future but I am curious if there is any "low hanging fruit" there for the current I/V's benefit.

I have built a few headphone amps in the last few months but I am very green on theory and application. I am in the weeds here. Any help you could offer would be appreciated and I want to learn!

[analog_sa]

Once you've replaced all the regs and improved the I/V there won't be much original dac left. Why don't you just build a dac from scratch, properly. It will be much easier. Or you really dig this case?

[wmincy]

out the OPAMP, put an I/V tube output would make a big difference, it's absolutely worth it!!

[espressogeek]

I am aware of this but I want to do this piece by piece. A DAC from "scratch" at this point is a bit beyond what I am prepared to do. Also it will let me evaluate the effectiveness of individual upgrades and the overall return on investment.

"Once you've replaced all the regs and improved the I/V there won't be much original dac left. Why don't you just build a dac from scratch, properly. It will be much easier. Or you really dig this case?"

Any help that can be provided on the various options of how to upgrade the power supply will be much appreciated!

[espressogeek]

I was thinking about the Lampizator tube output. What do you recommend?

Originally posted by wmincy
out the OPAMP, put an I/V tube output would make a big difference, it's absolutely worth it!!

[wmincy]

yeah, you read my mind!! Lampizator tube output is indeed a good approach: easy, effective and sounds good!!

If you have some direct-heated pencil tubes (5676, 5678) you can well fit it inside the small case.

[espressogeek]

Thanks wmincy. I will report back asap on one of these two tube outputs. If any other easy to build ones are available I am all ears.

I am also still seeking input on the power supply mods. Are the 3.3v and 5v mods all that is worth messing with?