[sdiy] Calling Harry or some of you knowing old hardware..

[Bob Weigel]

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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