RA-1062 intermittent buzzing

[dnn8350]

Any experience with this? My new (one month) RA-1062, normally virtually silent in operation, has on two occasions about a week apart suddenly begun to emit a fairly loud buzzing or humming noise from the amp itself (i.e. not through the speakers). The equipment had been on for several hours and was at a stable operating temperature. On both occasions, I turned the amp off, and back on again almost immediately. The noise went away. The dealer has suggested that it is a transformer 'teething problem', although Rotel tech support in the UK are willing to recommend replacing the unit. Any thoughts?

[Aussie Geoff]

Hi,

Transformer buzzing can be through 2 common causes:

1) A small DC current on the mains - which will, when present cause the coils in the transformer to buzz

2) A faulty transformer.

If it is intermittent - I an thinking the mains noise.. There are some filters that get rid of this and electricians can test for it...

If you haven't got a filter and surge suppressor- I'd buy a good one (see a few dealers and look for one that tracks active and neutral and removed DC current etc...) They are good anyway for cleaning up the sound and protecting the equipment...

If you still have the noise - then get a new RA-1062

Or you could get the new RA-1062 first and then the filter..

Geoff

[dnn8350]

re buzzing

Thanks for the suggestions. Actually, I did wonder about the mains, because I had the impression that the RB-1080 to which the RA-1062 is connected was buzzing as well. It was a little hard at first to tell exactly where the sound was coming from, but it didn't stop when I turned off the RB-1080, only when I turned off the RA-1062 as well, so unfortunately I'm not sure whether it was one or both. If it happens again, I'll be able to clarify this. Thing is, I already have an Olson Sounds Fantastic mains bar, so if it is DC on the mains, the Olson isn't removing it.

But would the mains DC explanation be consistent with the hum not re-appearing after power down and back up? Is it typically so short lived? I'll take the new RA-1062 if needs be, but obviously I don't want to do this if it won't fix the problem.

[Aussie Geoff]

Hi,

Try visiting www.hometheaterguide.com and www.avsforum.com and doing a "slow search" for "Transformer AND Buzz" as well as "Transformer AND Hum" you will get a number of threads that explain the different causes people have found (e.g Halogen lights, or dimmers on the same curcuit)...

You may also want to look at / post to, THIS thread in HTGuide... They are building a balanced power conditioner wiich will remove DC current and eliminate Buzz etc from transformers...

Geoff