Hi,

My 770 just started humming/buzzing. I'm not getting the hum from the speakers: it's coming from the amp itself. The sound is noticeable from across the room.

Any ideas?

Jeff

could be the x-former humming, but if it just started, then it is likely due to some power flux coming into your home. Try different outlets on a separate circuit breaker.

Also, power conditioner I had with toroidal x-former hummed because the nuts holding it in were not tight enough, so a few twists of a wrench and the x-former decided to behave.

You know, we're having a snowstorm here. Could be some kind of problem with the incoming power. In addition, the problem might have gone away -- it's too early to tell.

But anyway, thanks for the suggestion. I think you may be right.

Jeff

I am getting this hum from my 770 now. It is intermittent, but is becoming more frequent.

What should I try before getting on the phone?

Are you sure the hum is coming from the 770 or the speakers? The 770 has a slight hum (almost imperceptible) but my speakers had a very noticeable hum. I was able to trace it back to the cable TV wiring. I finally eliminated the hum by placing a 75 ohm to 300 ohm converter coupled with a 300 ohm to 75 ohm converter (very cheap-a couple of dollars each) and the problem was eliminated.

John

Absolutely positive the hum is from the 770, and not the speakers. Also, it comes and goes without much of a pattern. My speakers are dead slient with regards to any hum. The hum from the 770 is perceptible from 15 feet away.

One option is just to play everything loud and drown out the hum...

i think i have the same problem with hum from the speakers. while i am not sure that the hum is coming from the cable wiring i would like to try your solution. Where did you find the ohm converters.
thank you for any info you can provide
emile

The 75 ohm and 300 ohm converters can be purchased at radio shack and even Home Depot (at least are local one had them). The real problem comes from the cable company not properly grounding their system. Our local company, Cablevision, in my opinion did a very sloppy job in the wiring and grounded nothing. Call your cable company and complain.

In the meantime use the converters. Also, do a search on ground loop humming and you will find a number of possible solutions. This is how I got the idea of the 75 ohm/300 ohm converters.

John

Thanks for your response, I have time warner cable they also do not ground their cable system. I am curios do you run a high def or digital signal, if you do is there any change in the picture quality because of the added converters?

i have cable for internet and dishnetwork for video,i babysat each company when they installed.made sure they grounded, watched each company put on there ground straps,then made them undo it to scrape the paint off the pipe(come on i do car installs,you don't ground to paint)anyway,due to lack of spdif inputs i have to cable swap when i want to run puter audio through the system.as soon as i hook up the puter's spdif:hum,unhook it:gone.if i hook up the puter then unhook the sat. feed:no hum.can't just unhook the cables on the sat. have to actually unhook the feed.it's strange but it doesn't bother me so much that i lose sleep over it.btw,everything is on the same circuit,still no line conditioner though.

also i tie the puter in with my monarchy dip which is supposed to be a ground isolator(among other things)

john i tried the ohm converters and they worked to perfection as far as the humming noise is concerned, however i did notice a small degradation in picture quality. the tradeoff was well worth it so thank you for the info.maybe when i purchase a power conditioner the hum can be removed without the use of converters. thank again.

emile