[sdiy] Opionions on Switchmode PSUs for analog synths?

klangbau sauterw at web.de
Wed Oct 30 23:02:36 CET 2019

Hi Niel,

I'm testing several DC/DC or similar switching converters and in summary
all produce ripples in a different ways, also depending on switching
frequency of power switcher or wall wart. We build a +-12V power supply
for use with  19V laptop power supply.  It is working but with more or
less ripples, you can hear sometimes. I identify ripples by ear in our
VCO complete decoupled with +-5V/Tl431 with a 30W DC/DC converter.

Look at Dieter Doepfer's  power supply to learn how to avoid it: Use
+-15V switcher and +-12V linear converter.

It took a few years and a testing to understand Doepfer's solution. Rob
Hordijk did it in a simalar way.

willi sauter

Am 30.10.19 um 21:45 schrieb Neil Harper:
> so i'm putting together a new diy modular system, it's been over a
> decade since i built my last ones. my knowledgebase is firmly in the
> horowitz & hill era, so my previous psu was an lm317/lm337 based affair
> that took a 16VAC wallwart to power.
> that psu worked fine, but i'm noticing the 16VAC wallwarts are
> increasingly hard to find, almost impossible in europe. more of my gear
> is now coming with a switchmode dc wallwart and an internal switchmode
> power supply to generate internal bipolar (+/-12VDC) supplies.
> i was always told that switchmode power supplies suck for audio, so
> taking a switchmode dc wallwart and then putting it into another
> switchmode powersupply seems like it would be a recipe for noise - but
> this seems to be what is inside almost every product now. the forgiving
> input voltage range (9 to 18VDC for example) is very appealing and so is
> the availability of dc supplies.
> there's a lot of these encapsulated supplies, delivering +/-12VDC:
> https://www.jameco.com/z/DKE10A-12-MEAN-WELL-Power-Supply-Encapsulated-DC-DC-2-Output-12-Volt-12-Volt-0-42A-0-42A-10W-5-PIN-DKE10A-12-MEAN-WELL_217092.html
> anyone successfully using these things in synths? how are they comparing
> to old school rectified linear regulated power supplies? what's your
> favorite pizza toppings? are you doing anything special on the rails to
> filter for switching noise, etc?
> --
> /// Neil Harper
> /// Every Wave is New Until it Breaks
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