In article ,
David Looser wrote:
"Jim Lesurf" wrote in message
...
In article , Don Pearce
wrote:
On Sun, 20 Dec 2009 12:22:40 +0000 (GMT), Jim Lesurf
wrote:

I guess designers of commercial audio amps back then were more
habituated to using transformers than nowdays. I didn't know about the
above, but recall that some early domestic transistor amps included
things like coupling transformers.

How about a current guitar practice amplifier?

http://www.soundthoughts.co.uk/look/pignose.jpg

The idea is to sound like a proper valve guitar amplifier, and it sort
of does it.

The transformers look quite small. What's the scale of the picture?

They do, compare with the size of the screw-heads.

I did once do a 'theoretical' design using two bipolars and couple of
transformers to make a SET power amp, just to work out what kind of
gain, etc, you might get. But never built it as it didn't seem worth
trying to get suitable transformers. Maybe the above did it anyway?
:-)


That looks like a push-pull amp to me. Aren't those a pair of TO220
transistors either side of the larger transformer?

The size of the output transformer looks more suited to 1 watt types.

--
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Dave Plowman London SW
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