Hello,
I have worked on a few of these SC 120's. I am perplexed by the way they designed the Slave outputs on the front panel. When there is a plug in those jacks, you essentially end up with about 120V on the tip of the jack.
It looks like it floats the cathode of the 1st 12AX7...I only know you get a decent ZAPP if you happen to get across the other end of the wire.
It looks like maybe they're trying to use the outer shaft end of the 1/4" plug to do some switching when it's inserted. Pretty unsafe way to do it...if the ground sleeve of the jack is corroded or loose, you get the 120v right to ya.
Granted, not much current there, but what do you think of this. I have been merely defeating the jacks as a safty measure.
How do you deal with this? thanx, glen
I have worked on a few of these SC 120's. I am perplexed by the way they designed the Slave outputs on the front panel. When there is a plug in those jacks, you essentially end up with about 120V on the tip of the jack.

It looks like it floats the cathode of the 1st 12AX7...I only know you get a decent ZAPP if you happen to get across the other end of the wire.
It looks like maybe they're trying to use the outer shaft end of the 1/4" plug to do some switching when it's inserted. Pretty unsafe way to do it...if the ground sleeve of the jack is corroded or loose, you get the 120v right to ya.
Granted, not much current there, but what do you think of this. I have been merely defeating the jacks as a safty measure.
How do you deal with this? thanx, glen
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