Help with McIntosh Repair Facility

@samzx12 

Well thank you for the update. Now go listem to your Blue Meters.

Thanks dill. Just realized I never answered your original question. Did I try the 2 and 8 ohm taps. No I didn't. 

Great news, glad it all worked out for you.

I want to thank everyone who contributed to this thread (even aniwolfe haha)  Much appreciated :)  With the help of Monty a fellow audiogoner he hooked me up with a retired McIntosh repair guru and we took my amp to him this past Friday. He bench tested and found the bias was a little off and also calibrated the meters.  He found the left channel meter was reading high of all things.  This shocked me but hey they both read the same now and both channels are healthy and putting out equal power. Listened to the amp over the weekend and so far all is well.  It's also a good piece of mind that the amp was serviced by a professional and he gave it a clean bill of health. 

No because there is an issue to begin with and I want to get it resolved.  I did switch the speaker cables for both channels at the amp and the problem follows from the right to the left.  Measured the dB levels using a test tone and there is a 8-9db difference.  Two sources have told me they think it's the bias but we'll see hopefully very soon.  

OP, it sounds like when you switch cables at all is good except r&l channels are reversed, did you try to leave that,and change pre end also, that would fix channel reversal 

@aniwolfe Lamont is taking it to the local Watts electronics repair shop lol. 

@samzx12 

Try Sanford and Son or maybe Dan Aykroyd?

@loveallaudio Messaged you privately. 

Chevy chase / Lakeshore 

@loveallaudio I called Barney Miller and they can't work on it. Actually talked to the service department and he really offered no suggestions other than McIntosh.  

Where in Lexington are you?  I'm in Hamburg.  

I live in Lexington too, what about Barney Millers? They are a McIntosh dealer now.

They used to have a good service department as well.   

Mntyh please shoot me a PM. I do not disconnect it often. Only recently trying to figure this issue out. I’m in Lexington.

Took the top center cover off today looking for anything obvious but all connections were tight. I just dusted and wiped down what I could but issue still exists.  

I live in Kentucky,got a good contact. He's retired now but,he might have some suggestions. The bottom cover may need taken off and check the terminals. My MC 500 got a little lose. How long has this been happening. Do you disconnect it often?

+1 oldhvy - He's a Mac expert.

Jetter great idea. Thank you. 

Hi Tim, 

Thanks for responding.  Much appreciated.  Not sure if you noticed I mentioned when I put another amp into the system all is well.  I placed a MC402 in over a week ago and it sounded perfectly balanced so this tells me the issue is more likely the amp.  Wouldn't you think so?  I'm going to put some RCA interconnects in soon and see if this solves the problem.  Hell I've switched and substituted every other cable in the system and the issue doesn't go away. I'm inclined to think it's something relatively simple with the XLR input on the amp. I've also cleaned with Deoxit the XLR inputs on the amp and it didn't help.  

I think hendrixinc has the right idea.  It can't hurt anything and really quick to take off the top and check out the speaker and input connections inside the amp to insure all is ok.  Best to unplug unit before looking about.

I agree with oldhvymec

I’m not buying into “It’s the amp”.  If you set it up one way and the amp works perfectly, and then change the set up and you have a problem; it’s probably the set up, not the amp.  From your test result from switching the inputs your bad channel is telling you, “I”m showing you I can provide perfectly good, balanced music if I”m given the proper input”.  That is enough to tell me your amp is working as it should.  
My suspicion is it’s either something upstream, or the interconnect cord and/or the XLR input plug on your amp.  Could be an intermittent soldering fault in your interconnect or XLR connectors that cures itself when positioned slightly different.

When you have the inputs reversed at the amp and the amp is all balanced and the meters match, have you tried leaving the connections reversed at the amp and then reversing the interconnect connections on the upstream component (while not moving interconnected wires any more than necessary)?  If your VU meter levels still match you would now have left music coming out of left channel and right music coming out of the right.  At the very least you would have good music to listen to while you try to figure out where the problem is.  Meanwhile, with both your left and right channels playing together as they should, you can be 90% assured it ain’t the amp.  (Still could be a bad connection or part in or around the input section).

I’m not familiar with your equipment. Do your amp and your upstream component both have RCA connections as well?  If so, you might try using the RCA route to see how the amp works. If the problem disappears the amp is fine.  If the L/R problem remains, it is the amp.

Just some thoughts from a guy who has many components tied together in his system and occasionally has to “find the problem”.

Good luck,

Tim

Fred I wish that was the issue.  

i had similar problem with my mc252. i got my ear syringed and it was balanced

Suggest performing a deep Google on George Meyer before using them.

I’ve lived in the Los Angeles area since 1977.

DeKay

+2 Ryan at Audio Classics.

Dill yes so won't be cheap to ship.

The amp weighs 110 lbs. and the OP lives in Kentucky.

@rhg3 3 +1

I had my MCD201 repaired @George Meyer in LA. they did a great Job.

I thought it might be a goner, speed fast and slow and skipped badly if it could

find and load the disc.

They replaced the laser assembly and found a bad cap in the power supply.

works like brand new maybe better it is extremely quiet now.

only took 3 weeks from drop off to pick up!

$ 80.00 to check out. 

+1 for Audio Classics.  They repaired my C220 preamp earlier this year.  Very reasonable.  Be aware that the McIntosh parts department are kind of jerks.  They had a part that was needed in stock, but wouldn't send it to Audio Classics.  At one point, Audio Classics sent a guy over to pick it up, and they refused to give it to him.  It was a $10 part.  I ordered it directly from McIntosh, and had it in about a week.  I sent it to Audio Classics and they repaired it promptly and shipped it back.  Nothing but great service from Audio Classics.  Ask for Ryan.

Talk with McIntosh, they have been great to me. I’m sure they will help. Also audio classics if that’s not possible, they might be able to help also. Ryan is my connection. 

Effischer thank you and Happy Holidays to you and your family.  I will definitely call Audio Classics Monday.  As far as the shop in Ohio he immediately pissed me off but who likes worse case scenario news and he might have my amp for quite some time. Plus a $350 bench fee is utterly ridiculous. Any repair that is half the cost of the amp is ridiculous also.  

@Barts  yes I can switch the cables many times and the problem persists. I changed amps and all is well.  So this tells me it's the amp but I'm just totally befuddled what the issue is.

I agree with all the above comments regarding the Westchester OH quote; totally out-of-line.  I also agree that your first call should be to Ryan Kilpatrick at Audio Classics in Vestal.  They are known world-wide for their excellence with all things McIntosh, and Ryan has helped me a number of times over the years with some very odd problems.  Check them out: https://www.audioclassics.com

Good luck and let us know how it all ends up working out.

Joyous and safe holidays to you!

OP, Good luck with your troubleshooting. I just wanted to add to the good advice you’ve already received that George Meyer AV is an excellent Authorized Repair Center for Mac and numerous other high end brands. 
 

They charge $80 for bench test/evaluation which is credited to the final repair.

I had a great experience with them and they are scrupulously honest.

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

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.

I had a similar problem. 

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

+1 Ryan at Audio Classics. They

rebuilt my C26 preamp.

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 live in the Phoenix area.  Recently I brought my MAC 6900 integrated to a reputable high-end store for repair.  They charged $90 for a look-see and $90/hr to do the repair work.  Unfortunately , you may not have other options in your area.

Had the same problem with my MA2275. Was one of the front dials that went bad. Actually the inner workings of it. My local repairman ordered a replacement and the entire job cost $200. Not saying that is what is wrong with yours as not familiar with MC-452 but checked out the front of it online and it has dials. Probably an idiot response from an idiot but best I can say. 

I'm in New Jersey if you want to communicate with me - PM me.  I have rebuilt entire amps for $2500!

Thanks Laps I'll reach out to your guy also.  

I switched the left and right XLR inputs at the amp and the meters are reading the same now. I don't even have to look at the meters and can tell the sound is balanced which is just weird. The cables are fine and no fraying. The XLR/ RCA switch is in the correct position. My source is a LUMIN T2. 

I do agree his prices are ridiculous and I'm looking elsewhere. Definitely calling Audio Classics Monday. The only downside is shipping costs which will be expensive.  

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

or audio classics.

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

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

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.

@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.  

$2500 was not for labor only. It was total estimated cost worst case scenario.  This includes board replacement if needed and any other parts.  He is a authorized McIntosh repair center and been in business for 30years. I do think the bench testing is out of line also.  He is located in Westchester Ohio. 

That is some expensive bench test. A test to give an estimate is normally 130-170.00 on the west coast. Sometimes it refundable, if they can't get to you before 90 days. It is still applicable to the total cost.
350.00 is WAY out of line and a 2500.00 est before looking. Geeze ship to the west coast it's less expensive. That guy is NUTS. 350.00 for look see. He ain't a peep show and he sure ain't a Roquel Welch..

He does have some BALLS for asking those types of prices though.. Give me the guys number. I'd like to call him and tell him he is WAY out of line on his prices. Most Mac repairs are under 500.00 + shipping. I've NEVER heard of a 2500.00 labor charge or parts for that matter. New trannies too boot.. Good Lord.

You called the wrong guy, Jefe.

Regards

Is the imbalance something new? Have you changed speaker positions, rearranged the furniture in the room, or made any other changes that might affect how the left and right speakers separatedly interact with the room? (One can always try headphones and see if the channel imbalance is still present.)

Another inexpensive test you can run yourself is to get a voltmeter -- plenty of choices for around $30 or less.  Then find and download a monaural 1 KHz continuous test tone - mp3 is fine for this.  Either burn to a CD or add to your streamer collection and play from there  At either the preamp outputs or speaker outputs, check the voltage -- it should be identical for both channels. This will help give you an idea as to whether you have a problem in one of your component's circuits or an acoustic problem in the room.

Good luck!