[sdiy] Calling Harry or some of you knowing old hardware..
sounddoctorin at imt.net
Fri Aug 31 11:39:39 CEST 2012
I was working on an old Knight unit...probably the first DJ unit. lol.
Turntable on a metal box that uses 6SJ7 preamp tubes that get quite
noisy when I turn volume up. I eliminated the power supply cap by
putting in a huge one which did help some but not much. Very quiet now
past the volume controls..very simple circuit there. Except... these
strange parts on the input. A series thing that is a.... battery
or..capacitor with uneven length plates on the schematic. With B.C.
written by it. One on each input and both are doing the same. If I
short one side of the device away from the grid, little difference. If I
short the side on the control grid then it totally eliminates the hum noise.
Now...these things...have like a wire going into a porcelain 'tube' on
both ends. And a piece those fit into that looks like a funnel shaped
washer with some rubber insert on one side... and there is a wire
crimped around the porcelain on both sides so it's just a U shape
basically with the open ends of the U crimped around both porcelain
pieces if you can picture that.
What were those supposed to be? Anyone? Never seen a part quite like that.
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