Internal power supply for my homemade analog multi-effect pedal.

[guitylerham]

Hello!

I am designing a ten-unit pedalboard that will consist of effect circuits inside a long enclosure. I plan to build most of the circuits from scratch, including the internal power supply (using a Weber 8-secondary transformer). I have a question about how I should design the power supply to minimize noise. There seem to be two ways to go: one is have the transformer/regulator/rectifier/capacitor circuit in one centralized area and have the 9v wires then go to each circuit, the other way might be to have the transformers in one place and then run the unrectified/regulated secondary taps to each effect circuit which will then have the rectifier/regulator/capacitor circuit onboard with the effect circuit itself. Is there any logic to doing something like this? I just want minimal noise with this internal transformer setup.
Looking forward to discussing!

[Mike Burgundy]

I''d say keep the unregulated stuff with the transformer, out of the way of the audio circuits (especially high gain and high input impedance stuff!) and only run long DC lines. Power supply impedance is low enough so you won't get into trouble there, and you don't have long wires going everywhere acting like broadcast antennas trying to inject 50/60 or 100/120Hz into bits of circuit where you don't want it. It's probably not too much of a risk anyway, but this is the surest way IMHO. The grounding scheme is possibly more important  -look into star-grounding. Rummage around on GEOfex, there''s a lot there on good grounding practice (and *loads* more), the info on tube amp grounding and supply schemes also applies to low-voltage effects.

[guitylerham]

Thanks Mike, that makes sense. I agree that grounding may be a more important area of concern. I've been reading up on ways to do proper grounding. It is a confusing area of design to say the least. Still trying to create a solid mental picture of what grounding is and how it should be done. I appreciate the info!

[defaced]

See if you can find a copy of Tim Williams Circuit Designer's Companion.  The first chapter covers grounding in a very in depth and understandable manner.  You might be able to preview most of the pages on Amazon or some other online retailer.

I agree with Mike, run the DC wires.  DC doesn't couple very well, so you will have lower risk of noise ending up in your audio.  Keeping them against the chassis will also help to shield noise emission, twisted pairs could help too. 

While you're reading up on grounding, also add lead dressing to the list.  That will be the other X factor that could make your project unstable/noisy/etc.