Sjöström Audio DIY forum

Projects => Power supplies => Topic started by: DeafBeef on October 08, 2010, 11:06:24 PM

Title: Power supply selection for Gamma 2 DAC
Post by: DeafBeef on October 08, 2010, 11:06:24 PM
heaveno,

What PS would you recommend for the Gamma 2 DAC:
http://www.amb.org/audio/gamma2/

I was thinking about Sigma 11:
http://www.amb.org/audio/sigma11/

But it would not fit the Gamma 2 horizontal footprint (I want PS in a similar box as Gamma 2) plus
I think PS here have better tech parameters (lower ripple).

Looks like SSR-01 configured to 5V should serve me well, but I am not sure.
I am only looking for readymade units. Also I would like to know what 110V transformer to pair it with.

Thank you
Title: Re: Power supply selection for Gamma 2 DAC
Post by: peranders on October 08, 2010, 11:13:37 PM
My SSR01 would fit electrically but the rest of the technical questions must you take with the supplier of the DAC.
Title: Re: Power supply selection for Gamma 2 DAC
Post by: DeafBeef on October 08, 2010, 11:57:11 PM
Thank you for a quick reply Per-Anders,

What about SSR02? I don't see any differences except the PCB color. Am I missing something?
Also transformer, any particular kind or brand you recommend? At http://www.amb.org
I will check the power requirements.

BTW: Right now my PS is Jameco Wall-Wart. Input 120V AC/60Hz 17W. Output 5V DC/500mA

I know that any transformer with a sufficient power will work, but I need an advice here.




Title: Re: Power supply selection for Gamma 2 DAC
Post by: peranders on October 09, 2010, 12:06:16 AM
It's a negative regulator. red pcb = positive, blue = negative.

My regulators must have 5 volts more than out so a 5 V regulator must have at least 10 volts in.
Title: Re: Power supply selection for Gamma 2 DAC
Post by: DeafBeef on October 09, 2010, 12:51:49 AM
Thank you for a clarification,

> It's a negative regulator. red pcb = positive, blue = negative.

Sorry, I see now. Somehow I missed it.

> My regulators must have 5 volts more than out so a 5 V regulator must have at least 10 volts in.

Got it. So, for 5V do I need exactly 10V or any value from 10V to 35V will do?

Few more questions:

- What about wires from/to regulator? Any shielding or length requirements?
- ready-made unit specified with AD825, can it be requested with AD797 instead?

From the pictures I see that you use HAHN transformers, I assume you like them the best.

Title: Re: Power supply selection for Gamma 2 DAC
Post by: peranders on October 09, 2010, 10:22:06 AM
The thing about a regulator is to take care of varying conditions such as input voltage but at some point the regulator won't work and this is when it has not enough inputvoltage. Max 35 V in and at least 5 volts more than the output.

I can manage AD797 at some extra charge.

HAHN is a very good german brand with high VA rating compared with the size and they have also a very good quality. A good example of high german quality.
Title: Re: Power supply selection for Gamma 2 DAC
Post by: DeafBeef on October 12, 2010, 04:18:40 AM
I was about to send an email to order it, but I noticed that it was tested with LM329/LT1028 combo and results are almost as good or better compare to LM329/AD797.

You mentioned that AD797 is less stable compare to AD825. What about LT1028? Do you think it is a better choice compare to AD797? 

Thank you.
Title: Re: Power supply selection for Gamma 2 DAC
Post by: peranders on October 12, 2010, 06:16:19 AM
A bit perhaps.