I finally got the 101-B set up in the Living room with the KM-60. All is fine in all functions with NO ADDITIONAL SOURCES CONNECTED. In PHONO ONLY, when I connect a T.T. (and I connected 3 different ones), I get a High Frequency hum/squeal that is volume dependent. Doesn't matter if it's connected to MAG 1, MAG2, or CERAMIC, The Noise is there. Frequency is about 10K by estimate. Turntables can be grounded or non grounded No difference. Changing Cartridges makes no difference.
Before I got the squeal, I had an intermittent in the V6 socket where the .02uf cap was grounding out due to the way it was sitting causing a 3-4db drop in volume on the RIGHT SIDE ONLY. Wiggling the tube could open the ground. So I got inside, found the problem and reset the position of the cap and retested to see if I had volume on the Right side.
Right side volume is now equal of the left, but the high frequency squeal, hum,hiss replaced it, and on BOTH CHANNELS. IT's totally dependent on volume level, can be reduced by applying the High Filter, and by turning the Treble all the way down. It doesn't go away until I disconnect the turntable from the amp.
The Phono section on the 101b has not been recapped, and voltages on V6 and V1 are within 1% of schematic voltages on all pins.
I'm gonna replace the .01 and /02 ceramic caps in the phono section with Films this weekend. and which ever ceramics that hadn't been replaced yet. I did notice that the Tube Sockets for phono tubes are hard riveted to the chassis
I'm debating on whether it would be a good idea to drill out the rivets and install rubber grommets (as in the receivers) and the attendant screws and nuts,then run a ground wire from the sockets to a ground point on the chassis between the tubes? Or is it a BAD IDEA?
Before I got the squeal, I had an intermittent in the V6 socket where the .02uf cap was grounding out due to the way it was sitting causing a 3-4db drop in volume on the RIGHT SIDE ONLY. Wiggling the tube could open the ground. So I got inside, found the problem and reset the position of the cap and retested to see if I had volume on the Right side.
Right side volume is now equal of the left, but the high frequency squeal, hum,hiss replaced it, and on BOTH CHANNELS. IT's totally dependent on volume level, can be reduced by applying the High Filter, and by turning the Treble all the way down. It doesn't go away until I disconnect the turntable from the amp.
The Phono section on the 101b has not been recapped, and voltages on V6 and V1 are within 1% of schematic voltages on all pins.
I'm gonna replace the .01 and /02 ceramic caps in the phono section with Films this weekend. and which ever ceramics that hadn't been replaced yet. I did notice that the Tube Sockets for phono tubes are hard riveted to the chassis
I'm debating on whether it would be a good idea to drill out the rivets and install rubber grommets (as in the receivers) and the attendant screws and nuts,then run a ground wire from the sockets to a ground point on the chassis between the tubes? Or is it a BAD IDEA?
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