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Old 25th Aug 2023, 4:14 pm   #7
Robert Gribnau
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Join Date: May 2017
Location: Konongo, Ghana
Posts: 500
Default Re: QQV03/10 as an audio amp?

A link to a Philips document about the QQE03/12, which is equivalent to the Mullard QQV03/10 (and the 6360):

https://frank.pocnet.net/other/Phili...n_QQE03-12.pdf

I think that the designation "double tetrode" is misleading. On page 6 of this document it says that it has screens connected to the cathode acting like beam plates. This would make it a double beam tetrode.

The Va/Ia curves (page 13 and further) don't have the kinks that are typical for tetrodes in them. There is some negative resistance going on at around 50 V but something similar you also see in the Va/Ia curves of beam tertrodes intended for audio.

On page 12 data for use as A.F. amplifier in class AB1 and class AB2 is given. The data for class AB1 and the curves on page 16 don't look that bad to me.

Attached is one of the schematics of A.F. amplifiers with this valve that I gathered through the years.
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