Simple Test Circuit for Tube Noise
PStamler wrote:
In theory. In practice, there are other issues, some of which Scott
has discussed above. But, if the source resistance is appropriate
(either inherently high, or made so with a transformer), tube circuits
can be as quiet as, say, a 5534 opamp.
Unfortunately, the thermal noise in the transformers is sometimes a
bigger worry than the noise of the tubes themselves.... and certainly
the interwinding capacitance of the transformer is always a bigger
destroyer of bandwidth than the tube stage itself.
I'm a big fan of tubes, it's the transformers I don't like...
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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