AV receiver has noisy PSU/fan how fix

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Gemini

429 posts

Ultimate Geek
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#110655 13-Oct-2012 12:21

Hi all,

I have a Pioneer AV receiver with a somewhat annoying hum.
It's a VSX-C501 which is a slimline all digital amp
I can hear the hum, which may have been there since new, over the show I'm watching sometimes
It's kinda annoying
Does anyone know if this is more like to be the PSU or fan and whether either of those might be standard commonly available parts I could replace myself?

Thanks

numfarr

329 posts

Ultimate Geek
+1 received by user: 7

#700674 13-Oct-2012 15:32

I have the same amp, it's not that noisy but peoples' perceptions of noise vary. To check whether it's electrical noise, disconnect the speakers or plug in some headphones and see if you can still hear it. The amp must be getting on in years by now so it may be capacitors or something else electrical. Check the intake vents and the fan itself aren't blocked with dust.

Usually you can find a fan with a similar size, voltage, and airflow, just make sure the replacement will fit properly and blows about the same amount of air in the same direction. It's a 24 volt DC fan. The amp has no other ventilation so it's crucial to get this right or the whole thing will melt down.

Gemini

429 posts

Ultimate Geek
+1 received by user: 23

#700692 13-Oct-2012 16:59

Ah same model eh. I bought it new on clearance. I had more bulky boxes to fit in the cabinet back then. Haven't seen anything of similar thinness since. I can hear it running sometimes over the tv audio but "noisy" was overstatement. Have you noticed if yours is getting louder as it gets older? Cheers

numfarr

329 posts

Ultimate Geek
+1 received by user: 7

#700734 13-Oct-2012 18:50

Gemini: Ah same model eh. I bought it new on clearance. I had more bulky boxes to fit in the cabinet back then. Haven't seen anything of similar thinness since. I can hear it running sometimes over the tv audio but "noisy" was overstatement. Have you noticed if yours is getting louder as it gets older? Cheers

The fan didn't seem like it got any louder, it did start getting some "digital interference" type noise that you could only hear on headphones though, which I would guess is bad capacitors somewhere.

I just moved the Pioneer to the office and replaced it in the lounge with an Onkyo to get DLNA compatibility. I don't know why they have to make the amp boxes so big these days, it's not like they really need the back panel space, especially with HDMI.

Gemini

429 posts

Ultimate Geek
+1 received by user: 23

#700830 14-Oct-2012 07:32

I think the main reason is they are analogue amps that generate more heat than our digital pioneer so need a bigger case - the analogue runs much hotter yeah?
Also I think there's this customer mentality that bigger heavier amps are better quality amps so spending more money manufacturing a smaller case would be pointless
There's a C301 going cheap on trademe now but I don't think I've seen a C501 so a bit rare

numfarr

329 posts

Ultimate Geek
+1 received by user: 7

#700952 14-Oct-2012 13:00

Gemini: I think the main reason is they are analogue amps that generate more heat than our digital pioneer so need a bigger case - the analogue runs much hotter yeah?
Also I think there's this customer mentality that bigger heavier amps are better quality amps so spending more money manufacturing a smaller case would be pointless

Well they all have analogue and digital stages in them, and the newer amps need a lot more computing power to handle DLNA, Airplay, Internet radio and whatnot. So arguably they need more cooling, but it shouldn't be that hard to arrange without a monster case. But I think people expect a big box when they buy a separate home theatre amp, so it's partly fashion and marketing.

There's a C301 going cheap on trademe now but I don't think I've seen a C501 so a bit rare

Actually I realized mine is a VSX-C301, not a C501, although they look like they have the same case.

Dunnersfella

4100 posts

Uber Geek
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#701147 14-Oct-2012 21:04

A top end amp will run a top end power supply (whether it be Mosfet or whatever the flavour of the month is) - and from there you garner great sound.
A low end amp (slimline Pioneer's / Onkyo's etc) will effectively be running on clock radio power supplies, so the case makes sense. And believe it or not, but best practice in designing an amp will call for a dedicated analogue input board, a dedicated board for digital inputs / output, as well as plenty of space for the power supplies etc etc. Some of the top end amps do go overboard with inputs though... I mean, S-Video, VGA... really?