[sdiy] Transformerless Power Supply

[Tim Daugard]

>From: "Paul Schreiber" <synth1 at airmail.net>

It's a small switching supply. It *does* use a transformer, but not a
60/50Hz
one (more like a 250Khz one).
>

> It claims to be a "Low-noise transformerless design" and immune to
60hz hum..
> how does something like this work without a transformer?  Is this a
waste of
> $40?  I've got some 9v wallwarts lying around.. is it safe to daisy
chain a
> few guitar fx circuits off one of these?

Musicians Fiend has one item wrong in there ad. It provides up to 1.7
amps total. Most 9V batteries are pretty well used at 60-100 mA so
this can easily power up a few FX modules.

My power supply I build is about $10 for 300 to 400 mA. I'l have to
watch to see if the put this power supply on sale after Christmas.

The most  impressive spec is 100 to 240V input.

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
http://home.sprintmail.com/~daugard/synth.htm