🚀 go-pugleaf

In article <1228@heurikon.heurikon.com> johne@ex.heurikon.com (John Eckrich) writes:
>map@zeppelin.rutgers.edu (O. C.) writes:
>
>>My brother and I are building guitar amps.  Any help with inexpensive
>>sources for step up transformers(120->350)?

>Use a 40V (ie. 120 -> 40) transformer, and plug it in backwards.


        NO this is dangerous!  A transformer has sufficient inductance
to ensure that at its rated input voltage and frequency, current is
limited so that the transformer iron does not reach its magnetization
limit.  Above this limiting current, the transformer is a short circuit.
The 40-volt winding is lower inductance than the 120-volt winding,
thus will proabbly saturate the transformer, and burn out your
fuse (if you're lucky).

        There's lots of old vacuum tube equipment around that
used moderate amounts of current at high voltage; for that matter,
a microwave oven transformer goes from 120 to 1200 or so (some
vacuum tubes are still around...).  Look for an appropriate
unit in a disused piece of equipment... somewhere.
        Parenthetically, 120/220V transformers for voltage conversion
are relatively common; 220VAC rectifies to about 300VDC; would
that do?

        John Whitmore