In article , Ian Bell
wrote:
Jim Lesurf wrote:

In article , Ian Bell
wrote:
In designing a semiconductor preamp you usually aim for a low
collector current in the first stage as one method of minimising
noise.

Which "you" do you mean?... :-)

The noise level from a "semiconductor" preamp may be lower with a
higher current. Depends entirely on the device type, impedances, etc,
etc.

Slainte,

Jim


Jim, I expected better of you. Sometimes I wish people would just read
the question and try to answer it rather than critique it.

I was not doing a "critique" on your question. Just pointing out that what
you'd said above - which was not your question - was incorrect. :-)


I have had several responses to this post in rec.audio.tubes and not one
has actually addressed the question. I am looking for some guidance on
low noise tube preamp design and particularly the effect of anode
current. Can you help?

Not really. So far as I know if you require low noise then the sensible
approach is to use solid-state devices designed for such purposes. I'd
expect the noise level of a valve to be higher if only because of the
higher levels of thermal noise. So I'm afraid I've never even tried
designing a low noise valve amplifier myself.

Slainte,

Jim

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