Help with McIntosh Repair Facility


My MC452 is having an issue with the right channel that's a little weaker than the left.  Not by much but definitely noticeable.  Have been trying to diagnose the issue and everything so far points to the amp. I'm using XLR and have changed ICs , preamp tubes, cleaned amp inputs, etc.. but the head scratcher is if I switch the right and left IC inputs on the amp the sound or output is balanced. The meters are in alignment as they should be. The only issue is of course the right and left channels are opposite now.   I've spoken with an authorized repair center and bench testing is $350 and worse case scenario the board needs replacing plus labor can hit $2500 which in my opinion is ridiculous.  Has anyone experienced this issue or have any ideas or know of a reputable or more cost effective repair facility? I'm in Lexington KY.  Thanks in advance.  

Ag insider logo xs@2xsamzx12

I switched the left and right XLR inputs at the amp and the meters are reading the same now. 

I'm wondering if your problem is upstream. You said you didn't want the left and right channels switched but you can switch the source and get back to the correct channels. Not sure your amp is the issue if you can switch channels and it sounds right. 

I had a similar problem. 

Was under warranty and they covered everything.  Took 3 months to get the parts 

I had this same issue.  Turns out in my attempt

To tighten my speaker Spade connectors over a period 

Of time on my 8900, the binding post nut on the inside became 

Loose and cause a low and intermittent signal .

Took the cover off, tighten up. Fixed. Thought I was going to be without 

It for a few months but this worked.

Are you sure that the problem is consistent with the cable L/R swapping?

In other words, can you switch the cables 100 times and get the same result?

Do the test that @mlsstl  suggested and then take it a step further by measuring

the output of the pre at the cable ends.  Also, try different cables. 

I once had a cable that had one strand just barely grounding the positive, drove me nuts because switching the cables L/R would "fix" the problem, and then it would reappear. Took a jewelers loop to finally see it. And yes the cable checked good on a VOM simply because I was moving it around. 

Regards,
barts