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Old June 5th 04, 12:04 PM posted to uk.rec.audio
Dave Plowman
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Default Anyone Got a Cheap Valve Power Amp or Integrated Amp For Sale?

In article ,
Nick Gorham wrote:
Secondly, if you look at the voltages on the fillament, one side will be
at a higher voltage than the other, by the heater voltage, no this means
that there is uneven bias along the length of the fillament, so I would
expect a uneven electron flow. Now I don;t know if thats actually taking
part in the difference, but I can't see how it can help. If you take a
extream example, of GM70 running at 100ma current, and the fillament
being connected via the normal two 100R resistors, the 20v filament
supply seemd to me to mean that o current flows in one leg, and 200ma in
the other.


The same applies to an AC heater. Only at 100 times a second. Nicely
inside the audio band. Be interesting to use HF AC - outside the audio
band - and see how it compares.

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Dave Plowman London SW 12
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