[sdiy] Ferrite beads or 10ohms resistors in series with +/-15vdc ??

[Antti Huovilainen]

On Fri, 22 Jan 2010, Jean-Pierre Desrochers wrote:

> I'm using 12 X 12bits DAC's here, a douzen of opamps and don't want to 
> disturb my 1v/oct outputs because of not stable supply voltages..

There's a simple solution to your problem that has nothing to do with 
either 10 ohm resistors or ferrite beads: Use LOCAL voltage references on 
all critical boards (read: anything that requires accurate V/Oct 
tracking). Your boards will no longer depend on exact supply voltage and 
you will get much reduced interference from switching LFOs for example.

TL431 and LM336 voltage references (to give two common examples) cost 
peanuts and will give stable local reference. TL431 can even be adjusted 
with two resistors to give any voltage between 2.5V and 30V.

Ferrites are still useful for blocking out RF interference in inputs and 
outputs.

Antti

"No boom today. Boom tomorrow. There's always a boom tomorrow"
   -- Lt. Cmdr. Ivanova