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Tiny, cheap DIY power supply for Janus preamp

Started by okto, October 26, 2022, 11:53:18 PM

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This little guy on Amazon takes 5-35VDC and outputs +/-15VDC. Wired it up last night and it works great with my Janus preamp—well, it powers it on, at least, turns out the preamp doesn't really do much amplifying. :P


Thirteen bucks?  I am tempted to get it just to play with.

What are you using for input power? 
A nine volt battery won't last long, nor provide much current.  (But this I want to try.)

If your Janus preamp "doesn't really do much amplifying" then something is obviously wrong.  "DrOK" Micro Boost Voltage Converter...



I'm using a regular ol 12V wall wart.

I didn't bother to diagnose the Janus too much, just shotgunned mostly new caps (couldn't find a couple of them at the local electron hut) and replaced the opamps with TL072s. Works fine now, although I'm getting some leakage of the tremolo oscillator in the audio output...very likely the remaining two NP electrolytics I didn't replace.

I did notice that the Janus output doesn't sound quite as nice as running the harp output directly to my MixPre. Listening to it critically, I think the attack isn't quite as snappy through the Janus, missing a little of the "bite of the bark," so to speak. I can get a matching tone with the treble and bass sliders, but the attack is still just slightly muffled or damped. May play with swapping out capacitor types in the audio path, my suspicion is one of them is acting as a mild low-pass filter.