My dac comes with an external 15V small and cheap wall wart psu. A friend of mine measured it and it produces a lot of noise... not hifi at all as expected.
I'd like to replace it with a more serious linear psu. The Dac has onboard regulators for all voltage lines (12, 5, 3, etc) including the analog section.
What is the best approach:
A) a simple linear psu giving 15vdc that uses just rectifiers and smoothing caps
B) a regulated psu using something like LM317, or LT1086, or even with dual regulators
I'm pretty sure that A) should be better than the cheap wall wart, but not so sure about the apparently better option B) is really problem-free. I remember that once I read somewhere (I can't locate the source unfortunately) that putting in series psu regulated with 3-terminal regs can create more than one problem.
I hope somebody can help!
I'd like to replace it with a more serious linear psu. The Dac has onboard regulators for all voltage lines (12, 5, 3, etc) including the analog section.
What is the best approach:
A) a simple linear psu giving 15vdc that uses just rectifiers and smoothing caps
B) a regulated psu using something like LM317, or LT1086, or even with dual regulators
I'm pretty sure that A) should be better than the cheap wall wart, but not so sure about the apparently better option B) is really problem-free. I remember that once I read somewhere (I can't locate the source unfortunately) that putting in series psu regulated with 3-terminal regs can create more than one problem.
I hope somebody can help!
So maybe just clean up the incoming 15V? It's DC right? Seen this SMPS DC filter?
https://diyaudiostore.com/collections/kits-power-supply/products/smps-dc-filter-p089zb-kit
a] Yep, a lot of wall-wart SMPS's produce a lot of noise, which is often a problem.
b] a simple linear wall-wart or supply can be a better solution. It doesn't need to be regulated, that happens inside the DAC.
b] a simple linear wall-wart or supply can be a better solution. It doesn't need to be regulated, that happens inside the DAC.
One tip.
Very often also in expensive gear the regs have no capacitance between their legs.
If 78xx regulators in the dac are used. It's written in the dstasheet that kerkos (ceramic condensers 0,33 mfd) are important for stability. Putting them in makes impulse response much better.
Very often also in expensive gear the regs have no capacitance between their legs.
If 78xx regulators in the dac are used. It's written in the dstasheet that kerkos (ceramic condensers 0,33 mfd) are important for stability. Putting them in makes impulse response much better.
Attachments
If two 78xx regulators in line are used ("cascaded") ripple can become better but you get a bit more noise.
With more modern regs this should be no problem
With more modern regs this should be no problem