Onkyo TX-SR503 Left channel AC Hum?

[Coyote]

Ok, I'm new here. I just put together my first real HT system with the Definitive ProCinema 60s and the Onkyo SR503 reveiver.

In a word (or two): I'm impressed.

I do have one concern with the receiver: There seems to be a faint AC hum or buzz in the front left channel. Normally I have to get my ear up to the speaker to hear it, but in a very quiet room, it's just audible enough to be annoying. The hum is present the whole time the receiver is on and with all inputs and modes, analog or digital. The volume level does not affect the level of the hum at all.

It's definately the left channel output, and it's not being picked up by the speaker wires: Connecting a different speaker moves the trouble to that speaker. Is my receiver defective, or is this just to be expected for the price range? After all, the left speaker terminals ARE closest to the power cord on this model.

If anyone can chime in on their own SR503 or shed some light on what else might be causing this, thanks in advance!

 

[JMO_PWR]

My mate had the same problem, your best bet since is to go and take it back to the dealer. As you mentioned it is close to the powersupply so it could be a defect. No this isnt to be expected for the price range, expessially from an Onkyo.

 

[Coyote]

Right on.

I exchanged it and the new one doesn't have any hum at all. Not yet, anyway.

This problem took a good 3 weeks to show up, naturally, after I had disposed of the packaging. Dealer was nice enough to RMA my dud receiver in the replacement's box, but this means I can't exchange it again.

If the wheels come off this one, I'll have to go thru Onkyo service. Joy. Is there anything that could have caused this? Overheating? The unit runs pretty warm, but never hot enough to go into protect or malfunction.

UPDATE: After an extended listening session, I can confirm the new one runs a lot cooler. I guess I had a bad power supply in the old one or something