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What should I do with my used Mcintosh amp?

 

sleepless in boston
Unregistered guest
I bought a Mcintosh MA 6100 a month ago on ebay. The seller described that there is some scratch in its volume control. It seemed as described so far, but other than the volumn scratch, I began to find more problem. When I play cd, the left speaker sounds weaker than the other one, and I hear some sizzling-like noise. It is not that loud, but it still bothers me very much. It turned out that the speakers don't have any problem. What should I do? Please help me.
 

Bronze Member
Username: Cheapskate

Post Number: 84
Registered: Mar-04
it sounds like you need to get it fixed. one month is a bit late to seek a refund.

you'll take a loss on your purchase, but should fare well for resale value as mcintosh is one of the most sought after brands on the used market and holds it's value very well.
 

sleepless in boston
Unregistered guest
Actually, tomorrow will be the 30th day after the sale ended. Is there still something I can do? Because I paid cash in person, for some reason, I haven't leave review yet for the seller. Is the problem that serious? How much would it cost? Here is an authorized service shop in Boston. Should I bring it to there? or send it to Audio Classic?

Thank you very much for your advice!
 

Silver Member
Username: Rick_b

New York USA

Post Number: 748
Registered: Dec-03
If you have an authorized Mac repair facility in Boston, I would take it there. Audio Classics is a fine establishment, but why incur the costs and risks of shipping? I take it that you do live in Boston. Good luck!
 

sleepless in boston
Unregistered guest
I think, I fixed the problem. After I changed the input source selection from aux to tuner, the left speaker gets clean quality sound. I'm very happy now,,,
My question is then, is it a temporary solution, or what?

Thank you very much.

 

J. Vigne
Unregistered guest

If this solved the problem there are most likely dirty contacts. A problem of older mechanical switches and connectors is their insistance on oxidation. The problem is solved until the oxidation affects the input you are using. There is no way to determine when this will occur. I would have the amp cleaned, either by a professional or do it yourself if you feel confident. At least once a year maintenance on a system will not only keep the noises away, but, will actually improved the sound. Give it a try and find out how much more music is on your discs. It is a cheap upgrade.


 

sleepless in boston
Unregistered guest
Dear J. Vigne
Please let me know how I can clean them, and what kind of solution I should use.

Thank you very much for your advice in advance,,,,
 

sleepless in boston
Unregistered guest
Dear Mr. Vigne
I saw you helping Mr. Ben Davis, and you've appeared here again. Please let me know how I can clean them, and what kind of solution I should use.

I thank you very much for your advice in advice.
 

J. Vigne
Unregistered guest

How confident are you of your ability to work around the inside of the amplifer? You will be pulling connectors loose and replacing them without bending small pins.





 

sleepless in boston
Unregistered guest
I'm not that confident on it. Maybe I should bring it to the service facility.

By the way, I heard that i can use q-tips to clean those connectors. Then, what kind of solution should I use?

Thank you very much,,,
 

J. Vigne
Unregistered guest

It's been awhile since I've had the cover off a 6100, there may not need to be much done in the way of connectors inside the amp. You can check when you have the cover off to clean the controls if you go that far. You can get the cleaning fluids at several places. A good place to start is Audio Advisor, http://www.audioadvisor.com/store/browsecategory.asp
You can also go to a pro sound shop if there are any in your neighborhood. Tell them what you want to clean and they'll direct you to your choices. (If it's not busy and you have the amp in the car, they might be nice enough to show you what and how to do this cleaning.) Stay away from the stuff Radio Shack sells. There's much better that will keep the contacts cleaner for a longer period of time. Before you begin I will sugest the best way to go about this is to take the amp to a shop for the first cleaning and ask if they can show you what to clean and the best way to accomplish this. While there the shop should give the amp a general check out and give you some idea of the overall shape of the components. There isn't much that can be predicted by a general visual observation unless a capacitor is leaking or a solder joint is loose, so there's not much you can look for while you have the amp open. But, on a bench the tech can check for things that you may not find.

If you decide to proceed with the clean up yourself the first place to start is the back of the amp and the connectors for speakers and RCA inputs and outputs. With a cotton swab saturated with cleaning fluid, scrub the outside ground portion of the RCA's until no more oxidation comes off on the swab. You won't be able to get the connectors shiny again, so you just want to make sure they are as clean as possible. After you've finished all the ground connectors of the RCA jacks, move to the positive side of the connector. Remove most of the cotton from the tip of the swab and saturate what is left with fluid. It's best to do this with the top cover off so you can see what you're doing. Give the connector a good cleaning of all surfaces paying attention to the positive pin. When you're satisfied you can't get them any cleaner here's how you clean them again. Take a spare RCA connector (buy a few at Radio Shack or the pro shop) and wet the connector with fluid. Insert it into the jack and give a few good twists. If the connector fits snugly onto the jack, you should be able to take the swab and get more crud off the jack. The more you clean away, the better the connection and the better the sound. Do the same type of cleaning to the speaker connectors and the end of the AC plug, they both oxidize as well as the jacks. Don't use anything abrasive, just the cleaner. There are some fluids you can apply after you have the connectors clean that promise to keep the oxidation to a minimum. If you want to use these fluids, the procedure is the same as for cleaning.

On the inside of the amp you will see the selector switch, the balance control and the volume control. On a McIntosh these are likely to be semi-sealed pots. Spray a reasonably liberal amount of cleaner into the small opening on the pots and rotate the balance and volume as you spray. Don't go to the point of the fluid dripping out of the control. Too much can be too much. Spray and rotate, spray and rotate. The selector switch is likely to be an open switch on the 6100. Give it the same treatment as you did the pots. If you feel the selector still is noisy (a crackling or humming sound) you can take the abrasive paper off a book of matches and trim the edges to just have the abrasive. Slide this between the contacts of the selector and give it a bit of a scrub. It won't take much of this to get the contacts cleaned. Any speaker selector switches or tape monitor switches that you can clean get some spray at this point. Spray and push, push, push; and, then spary and push, push, push.

That's about all you need to do for now. Before you put the cover back on, take a look to see if there is any evidence of leaking capacitors or loose conections It is usually a brown goo that collects at the bottom of the cap. Look at the output transistors and see if they appear to have ever been burned. look on the boards for any sign a resistor or capacitor has been burned and replaced. If you see any evidence of replacement parts try to determine if the replacement is the correct value by comparing it to the same part in the other channel. If everything looks alright, you can put the cover back in place and give a listen to your new system. You should do this as regular maintenance on a system at least once a year. Once you hear the improvement it makes it won't seem like trouble.



 

sleepless in boston
Unregistered guest
Wow! You are amazing!!!
How can I appreciate you for spending your precious time for me? I'll try to be a good audiofile myself, and teach other people just like you did it for me...... ^^

Thank you very much...
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