"punkinaro" wrote in message
oups.com...

René wrote:
On 21 May 2006 06:16:22 -0700, "punkinaro" wrote:

I bought this Yamaha Receiver R-9 at a garage sale, it sounds great (
way better than my more recent Technics receiver) and has a lot of
features. However, it produces a humming sound on one of the speakers,
which is drowned by the music once it is played. The sound has peaks
and valleys, kinda like a windy day.
The unit is very dusty inside, should I blow some air in it or not?
Thanks for the answers.

Does it get hot?

How does your tweeter look?

The amp may be oscillating. Older yamaha's are slightly famous for
that with certain speakers. The oscillation comes and goes, loading
the amp to the limit without creating much audible sound. When the
oscillation hits rail to rail the hum starts to be noticable. I did
actually witness a tweeter dripping out of the box slowly...

it sounds like it might explode anytime :-))
I will check to see if it gets hot, and check the tweeter.
One question : on the back of the receiver there is a "Ground" round
thing. Am I suppose to attach a cable or something else? ( excuse my
lack of proper terms, I sell sweatshirts, I am no technician...)
thanks again, man, you guys are good




--
- René

The " Ground " terminal on the back, is usually for use with a phono deck
( vinyl record playing turntable ). You will normally find on these devices,
a 'standard' stereo screened cable, which is connected at the deck end to
the two channels of the pickup cartridge, and to normal RCA jacks at the amp
end. There is often then a separate wire connected to the main metalwork of
the deck, which runs along in tandem with the screened cable, and terminates
in a fork connector, to go under that ground terminal that you mention.

The function of this wire is to tie the grounded metalwork of the amplifier,
to the metalwork of the deck, thereby grounding it also. Without this
additional ground, the (extremely) sensitive phono inputs will have tendency
to pick up all manner of hum, clicks and pops, particularly when you touch
the tonearm ( which also usually has its own thin groundwire going back to
the main metalwork ) or the start / stop controls etc.

Arfa