[sdiy] inductor based distortion

[jhaible]

What exactly happens when a guitar amp's output transformer
is killed (well, permanently degraded) by using it for
distortion at low frequencies ?

JH. (who killed his car today on the highway, but gladly got away unharmed)

-----Ursprüngliche Nachricht-----
Von: René Schmitz <uzs159 at uni-bonn.de>
An: Glen <mclilith at charter.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Gesendet: Dienstag, 3. Juni 2003 19:29
Betreff: Re: [sdiy] inductor based distortion



Hi List,

Glen wrote:
> At 05:48 AM 6/3/03 , Michael Zacherl wrote:
>
>>Hi,
>>wouldn't that kill (i.e. the core becomes a
>>magnet) the transformer after some time?
>
>
> Power amps made with tubes, commonly have several hundred volts DC applied
> to the output transformer's primary winding. It doesn't seem to "kill"
> those transformers.

Right, the iron used for those cores is magenetically soft. Very small
remanence. As soon as an external field is applied the remanent field
vanishes, and the material magnetizes in the direction of the external
field.

However the actual DC drop over the primary might be only some 20V or so
for a typical tube amp. If the core has a bias current/magnetisation
(single ended) then there is an air gap incorporated into the core to
keep the core from saturating.

Cheers,
  René

--
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159