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Posted to rec.audio.tubes
Ian Iveson
 
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Default triode/pentode switch in ab763 vibroclone

eduard wrote

hello I'm building a vibroclone, I have a hole for the ground
swicth I
won't be using, so I can install a triode-pentode switch. 40w,
Ab763
circuit, 2x6L6. Can it be done? do you have links/ schematic or
pictures? Do I have to change the output transf.? what switch to
buy?


A link to a circuit diagram for the vibroclone would be helpful.

Often, all that is needed to convert from pentode to triode
operation is to swap each screen connections from the HT to its
respective anode.

6L6 have max screen voltage much less than max anode voltage, so in
some circuits you need to be careful. General advice seems to be
that they can cope with exceeding screen limit when in triode or UL.
There may be a max anode voltage beyond which this stops being true.
Its a common question but I forget the answer. No doubt someone will
say.

cheers, Ian






merci eduard