Re: Question about grid behavior with triodes

Patrick Turner wrote:

Eiron wrote:
Patrick Turner wrote:
Wessel Dirksen wrote:
Hello RAT friends,

......snip...

So putting 2V rms on the grid of a triode with a fixed bias of 2.4v
may not be such a good idea. Here's a circuit to experiment with -
http://members.lycos.co.uk/fiultra/BatteryT68bis.jpg

--
Eiron.

2Vrms = +/-2.8pkV, and grid current would flow in a tube with fixed bias
= -2.4V.

However, as its done in the above fiultra preamp stage, is OK because
the gain attenuater is before the 417A and probably quite low level output would be wanted, and therefore
applied input voltage probably will be below 0.2Vrms. The bias of 2.4V suits having a healthy
huge 20mA bias current in the 417A
which is supposed to sound very well.

Yes, we all know that you wouldn't turn the volume control up enough
to put a positive voltage on the grid but Andre's circuit is still
wrong. It simply needs a resistor at the top of the volume control
or 'Input 2Vrms' correcting.

--
Eiron.
.

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