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#205074 - 04/22/08 07:45 AM Re: Active Auto On/Off on EP175 [Re: JohnK]
kazkru Offline
frequent flier

Registered: 12/27/07
Posts: 12
Ok, did a little experimenting last night. It's definitely the receiver/amp that is causing the hum and not the sub or the sub amp. As I mentioned, my receiver/amp is a tube amp, and when I unplugged it from the power source, the quiet hum on the sub stopped completely. However, with the receiver/amp still plugged into the power source, even with it turned off, the sub still hums. In other words, the receiver/amp is sending a continuous signal to the sub, which appears to the be the reason the sub is not shutting off.

I'm no electronics expert, but I guess my receiver/amp either leaks juice when turned off or it is not grounded properly.

Kaz

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#205077 - 04/22/08 09:03 AM Re: Active Auto On/Off on EP175 [Re: kazkru]
SRoode Offline
connoisseur

Registered: 03/20/08
Posts: 1277
Loc: Fishers, Indiana, USA
Are the Sub and Amp plugged into the same outlet? If not, try that.
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#205174 - 04/23/08 08:39 AM Re: Active Auto On/Off on EP175 [Re: kazkru]
MarkSJohnson Offline
shareholder in the making

Registered: 09/27/04
Posts: 11437
Loc: Central NH
 Originally Posted By: kazkru
As I mentioned, my receiver/amp is a tube amp, and when I unplugged it from the power source, the quiet hum on the sub stopped completely.


Aaaaahhhh... that explains it.

It's not hum that you're hearing, it's warmth!
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::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::

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#205177 - 04/23/08 08:54 AM Re: Active Auto On/Off on EP175 [Re: MarkSJohnson]
EFalardeau Offline
connoisseur

Registered: 08/27/07
Posts: 3397
Loc: Laval, Quebec, Canada
[quote=MarkSJohnsonAaaaahhhh... that explains it.

It's not hum that you're hearing, it's warmth! [/quote]
That's was really funny! \:D
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#205203 - 04/23/08 12:28 PM Re: Active Auto On/Off on EP175 [Re: kazkru]
alan Offline

connoisseur

Registered: 01/29/02
Posts: 3256
Loc: Toronto/New York/parry Sound
Hi kazkru,

Very good trouble-shooting on your part. Now you can try connecting a separate ground wire to a chassis screw on your tube receiver amp. Run the ground wire to a known ground if you have one (a cold water pipe?) and see if the hum disappears when you touch the ground wire to the ground, or you could try the center screw on a household AC outlet, if it's properly grounded.

An alternative would be to run the ground wire to a chassis screw on the rear panel of the subwoofer amp. That may eliminate the hum. I once had to run a separate ground wire from a big old Macintosh tube power amp chassis to the pipe underneath a basement bar installation. The reviewer/journalist (an icon on Canada's CBC radio network; for those with long memories, it was Clyde Gilmour of the network radio show, "Gilmour's Albums") was so grateful to me, he mentioned me on-air and gave the magazine which I edited at the time (Sound Canada) a nice plug.

A bit of a digression, but I mention it to illustrate the extreme measures that are sometimes necessary to get rid of hum.

Regards,

Alan
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Alan Lofft,
Axiom Resident Expert (Retired)

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