Quad II question: High B+ a problem?
To conclude, I did finally find some 5V4GA and those behave very much like
GZ32. Dropped the B+ voltage back to around 360v and this seems to work
well. Great sound. The transformers and choke get warm but not hot.
I am still trying to find out why Peter Walker's drawings say 340v. Perhaps
this was measured with the original QCII preamp drawing current. I dont have
one of those (yet).
** The Quad 22 stereo control unit only draws 4.5mA from the HT of one Quad
II - plus 0.5A at 6.3V for heaters from both Quad IIs. The mono QCII takes
under half that.
So the effect on the HT is tiny.
I almost accidentally tried a 5U4G at first, until I checked my old RCA
manual. 3A heater! Using this in a Quad would NOT be good for the
transformer.
** Probably do no harm, the heater voltage might be a tad low.
..... Phil
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