Fisher X100-B Right channel lower than left

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AudioNutz18

Active Member
I have a Fisher X100B with right channel lower than left. I cleaned all controls, switches and inputs. Cleaned all the tube sockets very well with nylon brush. Checked all the tubes and all are good. Checked all the caps and none are far off actually all read within 20% tolerance. Checked for drifted resistors but found none. What other causes could this be?
 
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I used to have this problem with my Sherwood and it ended up not being the amp at all--one channel would be much lower until I reached a certain volume and it would even out. One of my speaker cables turned out to have a bad solder joint where the spade lug had been soldered to the cable. It was hidden under shrink tubing. One day I bumped the cable and the sound started cutting in and out. If I had played around with swapping cables I might have figured it out much earlier. Anyway, once I resoldered the spade lug to the cable, the channels were even throughout the range of the volume control, and remain so today.

So maybe this isn't the problem you have, but it might mean that your problem isn't contained within the amp at all. Or it might mean that all of your components are checking OK on value and that there's a bad joint somewhere. Did you check operating voltages against a schematic?
 
Could be the volume control, they sometimes don't track well as they age. You could jumper the left and right VC wipers together temporarily as a test. If that equalizes the two outputs, remove the jumper and apply it to the top of both VC sections. These test will tell you if the problem is the control itself, and also whether it's in the power stages or ahead of the volume control.

Jack
 
^^ this

if jumping the volume control together doesn't fix it, see if the lower channel happens to have a phase reverse switch in the mix. Those get crusty and cause problems.

The other common issue after the volume control that causes imbalance is off-value feedback resistors.
 
My money would be on the volume control as well.
Did you try swapping the tubes from right to left channel and vice versa?
 
Yes I swapped tubes from left to right, cleaned all controls very well, cleaned all tube sockets, tested all of the tubes and they all test good with no leakage.
 
There’s
Dadbar said:
My money would be on the volume control as well.
Did you try swapping the tubes from right to left channel and vice versa?
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there’s about a 200ohm difference on the volume control between the left and right channel. The higher number is the right the lower left.
 
gadget73 said:
The other common issue after the volume control that causes imbalance is off-value feedback resistors.
Click to expand...
I usually don’t give advice since I’m a novice myself. I will give you my experience I had just a couple weeks ago. My Scott 299 exhibited the same symptoms, and it turned out to be resistors as gadget mentioned.

Good luck with your amp.
 
Have you done it? The results of those two tests will tell you if the pots are causing the problem, and also whether the problem is ahead or after the pots.
 
TriodeLuvr said:
Have you done it? The results of those two tests will tell you if the pots are causing the problem, and also whether the problem is ahead or after the pots.
Click to expand...
I haven’t yet, my question was which ones are the tops? You mentioned to put a jumper in between the tops of both VC I’m not sure which ones are the tops. Thanks
 
By "top" he means the "hot", ungrounded, input, or clockwise end. Counterclockwise from the back. All the same thing. On a schematic, it's at the top.
 
I think that's correct. The 22KΩ resistor (red-red-orange) is connected to the bottom (ground) end of the pot. If in doubt, you can confirm which end is ground with an ohmmeter.

Fisher Volume.jpg

Jack
 
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