Hello, I'm currently setting up my first hi-fi from separate components. I purchased a used Yamaha RX500/U receiver and JBL 2600 bookshelf speakers (8 ohmz impedance, so they should work). If I hook up one speaker to the receiver and press the speaker select (A/B) button, there's a slight hum. If I hook up both and press the select speakers button, there's a loud, high-pitched buzz/tone that causes me to lunge to de-select it. I hear this tone even with the volume, bass, treble, etc turned down to zero.
This happens even if I disconnect my Denon CD player, so I don't think it's a ground loop (but I'm a novice at this, so I could be wrong): one speaker, slight hum (could be because the receiver isn't grounded, I suppose), two speakers, hideous overloaded sounding tone. Does anyone have any idea what could be causing this? It happens if I connect the speakers to the A or B set of connection clips, and it doesn't seem to matter which speaker I connect to the left or right connectors. Any advice would be greatly appreciated.
Ah yes, adventures in buying used equipment! Any chance that you can talk to the previous owner? They could likely give you your best information but, in case you can't:
I know you are setting up your first system so the answers are likely to be negative but would you happen to have some other receiver that you could connect the speakers to? And/or different speakers to connect to the receiver. The idea is to localize the problem, as you have eliminated the CD player, to either the speakers or the receiver.
I would say the problem has already been isolated to the receiver. There are no active noise producing components in the speakers and without a source the receiver is all that's left.
"I hear this tone even with the volume, bass, treble, etc turned down to zero."
To clarify the issue, the only control that matters here is the volume. Bass and treble have no "0" point when they are rotated to their extremes.
" ... could be because the receiver isn't grounded, I suppose"
Receivers do not require grounding beyond what is provided by the AC power cable. Adding any other ground cable is likely to cause a ground loop.
Have you checked the operation of the headphone output? The headphone jack is fed from a small ic output chip rather than the output transistors provided to the speakers. However, no one should be able to miswire the headphone jack. My guess is the noise should occur in the headphones also due to power supply problems or a faulty master control ic so begin with the volume fully decreased and raise it slowly.
Just to be certain, you know you have the speakers connected properly, right? No stray strands of wiring to touch the receiver chassis or the other speaker cable?
This noise ocurs no matter which source is selected? How about with just the tuner, can you hear any actual signal through the speakers along with the noise or is it just noise?
And, if you connect only one speaker to only one of the speaker outputs, there is a slight hum? This occurs no matter which channel, left or right, has the single speaker connection?
But it's only when both speakers are connected to either the "A" or B" outputs that you hear the high pitched noise? ("A" and "B" speakers are fed from the same output transistors and the connectors are internally wired in parallel. No matter which set of connectors you use the same output transistors are driving the speakers.)
Depending on where you live the receiver might be wired internally for another region. The "U" version of the RX500 was the international or non-US version and it should never have appeared in the US market. If you live in the US, there could be several reasons for the noise. It's even possible his was a "receiver" out of an inexpensive Yamaha rack system of the same vintage which would make this amplifier all but absolutely worthless.
Receivers of this age can hum slightly, that would be "normal" for a receiver this old and would simply indicate leaking capacitors. I suspect most technicians would advise against repairing this receiver as repair costs would easily exceed the value of the unit. The money would be better spent on a new (or at least more recent version of new) product.
There really are no simple reasons the receiver should make high pitched sounds as grounding or capacitor issues produce low frequency - 60Hz and 120Hz - noise. High pitched noises are an indication of much more severe problems with the receiver.
Make certain you have your speakers connected properly, if you have any doubts about how to go about a correct connection, ask for assistance.
Check the headphone output for noise and, if you have the same problems with both speakers and phones, the receiver is shot. There is no reason to repair this product, it is too old and was too inexpensive at retail to pump good money into any restoration.
There are no user serviceable parts inside this receiver so, please, do not attempt any sort of probing about. You shouldn't have paid very much for this receiver therefore, if you confirm the phones also have problems, you have confirmed there is nothing to be done with this receiver other than return it as inoperative and get an exchange or a cash return.
I wouldn't spend any time with this receiver, there was nothing special about the RX500 that should warrant even the slightest concern for ditching it rather than spending more money on it.
I repeat, if the noise also exists on the headphone output, just go get your money back and find another receiver.
Thank you very much for the replies. I've borrowed some headphones and some old speakers for a more thorough check (I didn't want to risk my new speakers!). Looks like I "mispoke" (to use a horrible euphemism) before: it seems that it's only the left channel that's effected, and the problem seems to be related to the bass frequency (I can't have turned it completely down before). If the bass knob is turned on even a little, I get the tone from the left channel speaker (same with the headphones): no bass frequency, no tone. Both speakers can run off the right channel A/B connectors with the bass on. So....some kind of circuitry related to the channel fried, perhaps? I picked up the receiver cheaply, so I'll probably write it off to bitter experience rather than attempting to get it fixed (as you say, this is likely to cost more than the receiver itself).
"Jan, just to REALLY clarify, should the speakers be disconnected when checking the headphone output?"
It shouldn't matter since the two output devices (transistor and ic) are discrete circuits separate from one another.
If you'd prefer, you can try to find a shop that would work on this receiver and ask for an estimate of repair costs. Estimates run on average about $50. If you decide to proceed with the repair, the estimate price goes to the final cost. Otherwise, you've spent your money to be told it's not worth repairing the unit. Your biggest problem with that scenario is finding a shop that wishes to be tied down to a RX500. The line was not Yamaha's finest effort and most shops just stop fixing older gear rather than risk multiple failures beyond their control.