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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.  

samzx12
samzx12 OP
1,255 posts
 

@mlsstl. Believe me I’ve adjusted the speaker positioning, added room treatments and just about everything else to diagnose this issue. The telltale sign was dropping in another amp in the system and problem goes away. It’s the amp because you can watch the meters on various types of music and the right channel is consistently weaker than the left. Just by listening the imbalance is noticeable easily. When I switch the inputs at the amp the imbalance goes away and the meters coincide with each other.  

ghasley
2,563 posts
 

Send it to Binghampton...either Mac or Audio Classics. Not fixing it shouldnt be the option b.

 

Happens all the time in every industry. What he is actually telling you is quite useful: he doesnt know wtf wrong and needs you to pay him to figure it out on the fly.

 

Move on but much like anything in life, there is no free lunch. If you send it to either Mac or Audioclassics, you will have an amp that has been checked out by honest, knowledgeable and forthright people who know what they are doing and more importantly, a receipt for repairs from them will enhance the value of a not so new amplifier.

dill
2,635 posts
 

Have you tried the different 2 - 4 - 8 ohm speaker taps to see if the low output follows? 

oldhvymec
5,101 posts
 

Switch which inputs? You mean to another input or left to right? If left to right inputs cables fixes anything, how does that equal to an amp problem if ANY cable change fixes it. For some reason either I’m not understanding your description of the problem or the problem is a cable. What is the source?

I’ll say it again 500.00 is the norm for a Mac repair. With a transformer add 5-700.00. IF more than one failed I’ve never seen that either.. 50 years with Mac for me.. Currently 30-35 pieces of Mac gear I’m running lowered stock these days. :-)

Is there a RCA vs XLR switch, in the mid position or WRONG position, some weird thing like that? There is no frayed cable or any broken "LOOKING" cable. Input or speakers, not a single strand of wire anywhere is touching?? You ran YOUR hands overs every cable with a cotton glove. It will snag if there is a problem. A pair of cotton gloves is pretty cheap..:-)

Regards

laps
101 posts
 

Bobthetechaudio.com.  I have an amp there now undergoing diagnostics.  Bob is very easy to communicate with.  

or audio classics.

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