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Luxman R-117 distortion in the mid and upper range.

It occurs to me that it would also be a good idea to see what happens when only one channel has input. For example, if you only supply an input to the left channel, is anything heard from the right?

Also see if tone controls behave as expected, checking each channel by itself.

The questions in my mind being: is there some out-of phase content bleeding from one channel to the other, or is one channel inverting the phase, and how do these behaviors change over a range of frequencies?

(This all very much assumes I'm understanding the description of the symptom. Plenty of room for doubting that.)
 
chazix said:
If the block diagram in the SM that I have is to be believed (hardly a guarantee), the balance control is not enabled when using the CD input with "CD Direct" selected. Does that seem to be true?

It's not clear to me whether anyone has used the preamp in/out connections to localize the fault to either the preamp or power amp. Especially with a very odd symptom, I would think this would be high on the priority list.
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chazix: Thanks for your input. The Balance control appears functional in both positions as I recall. Just has low output on center imaging when in centered position. As soon as I turn the balance left or right just say 10 degrees on the knob the center vocals pop back in but slightly adjusted to left or right depending on which way the balance control is turned. I have never seen this happen before in other amps / preamps or receivers like this... Seems VERY ODD to me. I will try your other suggestions checking just amp separated from preamp but I really don't think that can be the issue as I have never seen an amp do this before. Also will try tone controls and other controls. I am wondering if bad analog switch IC's may be playing a part in this or possibly one of the Op AMP circuits is limiting only when balance controls is centered. I have not put a scope to it yet as I have not been feeling well and have not had the time. My best guess is a bad control or controls ( like balance or volume pot or both ) Wicked Weird I just don't want to clean controls and have that lead to total failure if they are unavailable after all this unit is like 40 years old now, and I read some posts warning to go easy cleaning these controls.
Thanks again Mr. Bill
 
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Mr Bill said:
As soon as I turn the balance left or right just say 10 degrees on the knob the center vocals pop back in
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Hope you feel better soon. But I suggest enjoying the nice weather before getting back to the workbench :).

Above observation seems sorta, kinda consistent with a theory that phase is being inverted in one channel. Not a slam dunk, though - my main reservation is that I don't understand why such a fault wouldn't affect bass even more than vocals.

I'll bet dollars to donuts that the tone control section, when engaged, inverts phase. It's hard to imagine how the tone control switch could be defective such that one channel engages the tone circuitry and the other channel doesn't, but physical damage to the switch might do it. This is the idea behind suggesting to listen to how the tone controls affect sound, one channel at a time.
 
Yes I understand what you are describing to me. The amp is going to a friend tomorrow that is better at troubleshooting than I am. Hopefully he can find the fault. Bass actually does not change much or some of the other background instrumentation when Bal control is centered bur-t definitely everything that is supposed to be somewhat centered in the sound stage disappears with a proportionate decrease in volume. I have a bad feeling it is worn out controls and I hear a lot of people saying they are no longer available probably because remote powered with actuator motors. Too many fingers pushing the remote buttons over the years I guess. Too bad this is otherwise a stunning receiver. The owner that brought it to me ( the OP ) is going with me to take it to another tech I know that is great at trouble shooting pretty sure he will find the fault hopefully not worn out controls.
Mr. Bill
 
I'll add that the tone defeat button can cause noise issues as well. On one of my 117's I get low level noise with the tone defeat off. You would think having the tone controls in circuit would be more likely to cause a noise issue...but not in my case.

Hope he gets it figured out. :lurk:
 
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