[sdiy] Battery power for eurorack

[Mike Bryant]

If you’ve got visible RF spikes you need a better PSU arrangement !   The problem is people are happy to spend money and space on adding linear smoothing but not on adding the equivalent components to a switcher, which includes decent screening for the PSU and smoothing components.   I stopped using linears in the 1980s because switchers overtook linear around then, and they’ve only got even better ever since.


From: Mattias Rickardsson [mailto:mr at analogue.org]
Sent: 31 December 2021 13:45
To: Mike Bryant
Cc: Quincas Moreira; cheater cheater; Synth DIY
Subject: Re: [sdiy] Battery power for eurorack

Mike Bryant <mbryant at futurehorizons.com<mailto:mbryant at futurehorizons.com>>:

> I don’t know why people think switchers have to be noisy.  To me there’s nothing worse than 50/100Hz still leaking through umpteen thousand microfarads of smoothing.    Apply that much smoothing to a >50kHz switcher and the noise would be below the cosmic background noise level.

Low audible noise, but perhaps that's not the only aspect. The RF energy from switchers is often clearly visible on a scope, in repetitive spikes at frequencies and amplitudes that vary a bit with temperature and current draw.
What happens when these spikes are added to a comparator threshold level in a VCO core designed with only linear power supplies in mind? :-)

/mr

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