In article , Iain M Churches
wrote:

"Don Pearce" wrote in message
...

I've been the minimalist route for amp design, and the problem is that
it doesn't stay that way. You always end up thinking "if I just do
this, it will work SO much better" and by the time you are done, you
have put in all the buffered current mirrors etc that really make it
work. And in the end, why not? The bits cost bugger all.

The cost is not really a factor. The idea was to design and build the SS
equivalent of Andre's simple SET amplifier, so that those interested
could build both for listening comparison.

Well, I don't know the design of SET amp you refer to, so can't comment on
it specifically. However when I had a student build a transistor SET amp
some years ago the expensive and difficult part was the o/p transformer.
This is a bit easier in some ways than for valve as it didn't have to
isolate very large voltages, and didn't have a large turns ratio. But you
still end up requiring a significant (expensive) transformer if you want it
to work OK even down to LF.

I don't know if I still have a copy of his project report. When I get a
chance I'll have a look for it. My (perhaps unreliable) recollection is
that the performance was limited by the transformer not by the choice of
gain devices. Hence such theoretical 'simplicity' can become quite complex
and costly to attain. Looks simple on a circuit schematic, though. :-)

Slainte,

Jim

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