Mcintosh ma6900 hum transformer


Hi folks, anybody know if hum from Mcintosh ma6900 transformer is a bad sign? And the left watt meter need more volume up to wake up, to start working, then i can put the volume to almost minimal and watt meter work normaly, all audio output working normaly.... i dont hear any hum from the speakers, just on transformer,

best regards from Slovenia/Europe
89ziga
89ziga,

I have owned many McIntosh amplifiers and integrated amps. I have never heard any hum from any of them ever. 

It it sounds like maybe you should send it off to Mac for a service. Their service deptarment is first rate and they will call you with a quote before repairing anything. 

I hope this helps. 
Norman
Normansizemore thank you for your quick response. I think you're right i need to send it to service, maybe you know approx. how much can this cost?

thank you very much, all good!

best regards
89, I had a MC7205 amp that had a hum that I was able to determine was the transformer vibrating. So I placed the amp on Sorbethane feet and it went away. Also that same amp did produce a "small buzzing" in two rear channels and I found lifting the ground eliminated that.  You may they that before you send it overseas.
Hi 89!

I think the hum and the meter issues are two different things.

Hum can be caused by having DC in the line, which can happen from a variety of sources, such as digital supplies or dimmer switches. A qualified electrician should be able to find out if this is the case. Also, see if it's really the transformer or the case. You may need to add a little damping material to the sheet metal.

The meter should be fixed.  It's probably a bad op amp or cold solder joint.

If it's DC on the AC line and you cannot stop it, an isolation transformer should fix the problem, but then, cheap isolation transformers will buzz on their own! :)

Best,


Erik
Thanks guys for all response... when i take off the bottom cover, the hum is really minimum... i think i need to change the feets on amp... but two more things i notice, now i have noise on speakers but it’s not buzz...( all electronics component are not connected on amp, just power cable), i havent got any noise before today. the second one is noise from power supply caps i think that noise wasnt there before today... 😐😐
89ziga,

I don't remember McIntosh service being especially expensive.. What was critical to me was that when they service your amp they will service the entire amp not just the problem. In other words if will be brought entirely up to factory spec.  Any and all issues will be addressed and they warranty their work.

Send it off to them, they will quote you before the do any work. It's well worth it.
N
I suggest Audio Classics for repair unless your integrated is under warranty.  Do you by chance have a REL sub base system running off of your integrated?
i wrote an email to Ryan(audio classics) a two week ago, but i dindt get any answer or respond... so i contact mcintosh directly to NY, they give me a contact from officaly service for mcintosh in Slovakia(bis auido)... i think i will send it there to repair...the shipping cost will be 240€ for both way.. i heard that audio classics is very good, but they dont reply on my emails.

thanks guys for all!
You may also want to consider the possibility you have "DC" on the line. Transformer hum (and not audible in the speakers) is a symptom. Have you added any appliances and/or dimmers lately?There are plenty of DC filters available. It would probably be worth having one even if that isn’t the issue. The meters are another story, but I suppose possible they too could be adversely effected by DC on the line.
Line DC apparently was making one of my amps hum and a PS Audio Humbuster III fixed it immediately. Great product you can still find for sale here and there, and I although know nothing about other DC filters available it's all a good idea. 
Thank for all replyes! the service department sad that device is ok, no need to repair, but i want to put led kit, anybody know how to get the led lamps? maybe some specifications?