[sdiy] Switching power supply transformers

[RMC]

> i've learned that switching is NOT good for synth-DIY.
> Anyhow i was wondering if you think that i could
> salvage the transformer (it's really, really small)
> from the supply to generate 5v/2A ?

No - it'll be designed for much higher frequencies than mains (50Hz or 
60Hz). It is only of use for its intended purpose as far as power supplies 
are concerned.


>The other thing i was thinking is that maybe if i'm driving only the
> logic part of the circuit with this, i could keep the
> supply as it is? Any thoughts would be highly
> appreciated!

If it is well enough shielded and filtered it would do OK as a power supply 
for anything - it all depends on the ripple when on load and off load.  You 
could easily use it in a lab test setup and see if you can see power supply 
noise on the logic rails, for example. SMPSUs might switch at frequencies 
from (say) 25kHz upto 200kHz, so that's the sort of ripple to look for.

Cheers

RMC, England