M-Audio Super DAC power supply mod/tweak

[Tachikoma]

Hello, this is my first ever post in the DIY section

Anyway, the M-audio super DAC currently uses a 9VAC 1A adaptor for power, and... I don't like it

So I have two options:

A. Get a torroidal power supply capable of supplying up to 2.78A

B. Mod the super DAC to use dc, in other words, replacing the entire power supply section of the DAC.

Edit: screw the budget.

http://f3.grp.yahoofs.com/v1/kKftQyJ...r%20supply.pdf

Here's a schematic of the power supply.

 

[Tachikoma]

*pokes up the thread*

 

[Zorander]

Check out this Yahoo group dedicated to the SuperDAC.

I'm using a custom-made 9VA 3A PSU. Don't know how much difference a torroidal PSU will make (don't even know if mine is toroidal or else) but there is certainly a very appreciable difference between the custom PSU and the smaller one. Anyway, I'm sure the knowledgeable people in that group can help you further with this.

Cheers!

 

[Tachikoma]

Heh, I joined that group a while ago >_> Btw, how much did you spend on that custom PSU?

 

[Zorander]

I had it built for around $30. I might take it back for some cable shortening and hardwiring (DC cable is too long and IEC mains input jack seems unnecessary). But as far as I can hear, the upgraded PSU does help the DAC to sound the way it was intended to be, that is an honest-sounding DAC.

 

[Tachikoma]

Hmm, thats about just right for my budget

Could you introduce me to the person who made that PSU for you?

 

[motherone]

You may want to just find a better wall-wart. Poke around for a 9VAC/2A or 3A wall-wart. They're not terribly hard to find on the surplus sites. I don't think there's a huge difference between the stock PSU and the upgraded ones (I'm using a 9VAC/3A desktop supply). You get a lot more from upgrading the guts of the DAC.

You can check out the upgrades I did on my superdac here:

www.motherone.com/projects/dacs/superdac

Biggest difference was obviously the opamps, then the dac coupling caps, and finally the power supply/bypass caps and the diodes.

 

[mirlo]

That upgrade confused me. Isn't a 5532 a DUAL op-amp, and a OPA627 a SINGLE op-amp??

 

[Tachikoma]

Quote:

I've been giving the power supply more thought, lately, and my ideal way of dealing with it would require removing the SuperDAC from it's enclosure entirely. Then, strip all of the pre-regulator caps and rectification diodes. Finally, build 3 outboard power supplies, +15v, -15v and +5v around Jung-style superregulators. I would use a 15VAC/2amp transformer with two secondaries, each going through full-wave rectification via MUR860 or another ultrafast rectifier diode. This, plus 2,200-4,700uF of capacitence per rail would power the +/- 15v section of the DAC. A second 6VAC-9VAC single-secondary toroid with full-wave rectification would power the +5v sectionThis should yield a great improvement on the analog output stage

Gee, how much would that cost?

How much power does the DAC consume anyway? Will 1.5A be enough?

Quote:

The next step was to desolder the JRC NE5532 opamps and replace them with sockets.

So you used an adaptor "thingy" and two OPA627s? Kewl.

*wonders if its actually possible, lol*

 

[Zorander]

Well... if I could find somebody with the right knowledge (and skills) to mod the inside of the SuperDAC, I would have done it long ago. Anyone here up to the challenge? I will pay, of course.

As for the one who made the PSU for me, I'm afraid it's not an option for you as the person is just a simple tinkerer with a little electronics store in a little-known place that I just happened to stumble into.

 

[Tachikoma]

Motherone: is it possible to bypass the opamps instead of swapping them?