Hum from speakers - Canadian TV, Computing and Home Theatre Forums

zachdini · 2012-05-27, 02:27 PM

This is my first post here so I'm sorry if this is in the wrong place.

I recently decided to set up my first home theater. Usually I listen to music or watch movies on my computer through my computer speakers (Soundsticks II) but I bought a vinyl player and decided to run everything through an old receiver.

The problem is that the Soundsticks are computer speakers and one of the ways that I found to wire them to my receiver is through a series of adaptors. The speakers have a 3.5mm jack that is converted to RCA which is then converted to speaker wire, plugging into my receiver. The problem is that the speakers output a constant (low volume) hum even when the receiver is off. When I turn the receiver on, the hum's pitch increases but still stays low volume.

It's a pretty old receiver and I plan on getting a new one but I don't think that's the problem. Is there a better way of connecting my speakers to the receiver that would eliminate the hum?

timlocke · 2012-05-27, 03:48 PM

Try reversing either the receiver power plug into the wall or if the speakers are powered as most computer speakers are, the speaker power unit plug but not both. This might cure the hum. I assume if the receiver is old it does not have a polarized or 3 plug. If it does you'd have to switch the speaker power.

Another thing. adapt the 3.5mm jack to RCA as you have done and plug those jacks into the tape out jacks on the receiver...if it has any or preamp out whatever they might be called.

SO you'd have RCA male to male Red and white from the receiver into a twin RCA female red and white adapter to a single 3.5mm jack.

I am not saying this would cure the hum but at least all the signals would match up.

zachdini · 2012-05-27, 05:31 PM

Thanks for the help!

I tried reversing first the speakers and then the receiver, making sure they both weren't reversed at the same time. The hum is still there and there's a faint static sound, as there was before.

The reason I converted the speakers all the way to speaker wire was so that I could turn these speakers on/off and send my sound to other speakers using the receiver's A/B speaker settings. However, if you feel like going straight to RCA would get rid of the hum and improve the sound, I'll give it a try. Under "tape" my receiver has REC out and Playback.

Yesterday, I saw someone in a similar situation mention that the speakers and receiver give off different voltage and someone recommended a device/adaptor that you run the setup through to correct it. I remember them saying it should cost about $20 but I can't find the thread or the name of the device. Do you know what I'm talking about?

57 · 2012-05-27, 06:18 PM

The output from the speaker terminals on the AVR is completely different (more power) than the output from the RCA jacks. You should not be "jerry-rigged" the way you currently are. If the AVR has a headphone jack, that may also work with appropriate adaptors, but that would turn off the speaker outputs usually.

timlocke · 2012-05-27, 09:05 PM

The use of tape out ( REC) should work perfectly. That output will be a standard 1Volt output from the preamp stage of the receiver just the same as the line out socket on a computer. Note that the speakers will be on all the time and you'll have to turn them off to silence them.

I am not surprised that swapping the power "polarity" ( not the correct term at all) did not work but there was a chance that a cheap power supply was leaving some ripple added to the signal. Hum in analogue audio has been a problem just about forever.

I agree with 57 that most likely using the headphone jack will turn off the other speakers...which my be just what you want. Just as the TAPE out, the levels and impedance should be correct.

2012-05-27, 02:27 PM	#1
zachdini Rookie Join Date: May 2012 Posts: 2	Hum from speakers This is my first post here so I'm sorry if this is in the wrong place. I recently decided to set up my first home theater. Usually I listen to music or watch movies on my computer through my computer speakers (Soundsticks II) but I bought a vinyl player and decided to run everything through an old receiver. The problem is that the Soundsticks are computer speakers and one of the ways that I found to wire them to my receiver is through a series of adaptors. The speakers have a 3.5mm jack that is converted to RCA which is then converted to speaker wire, plugging into my receiver. The problem is that the speakers output a constant (low volume) hum even when the receiver is off. When I turn the receiver on, the hum's pitch increases but still stays low volume. It's a pretty old receiver and I plan on getting a new one but I don't think that's the problem. Is there a better way of connecting my speakers to the receiver that would eliminate the hum?

2012-05-27, 06:18 PM	#4
57 Moderator Join Date: May 2002 Location: Toronto, Rogers, 8300HD, eHDD, Panasonic TCP65S1, Denon AVR4310Ci; 8300HD, eHDD & Sony KDL40W3000 Posts: 50,301	The output from the speaker terminals on the AVR is completely different (more power) than the output from the RCA jacks. You should not be "jerry-rigged" the way you currently are. If the AVR has a headphone jack, that may also work with appropriate adaptors, but that would turn off the speaker outputs usually. __________________ 57's Home Theatre (Latest equipment & photos) 57's Optimization Services (Home Theatre Optimization)

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2012-05-27, 03:48 PM	#2
timlocke Join Date: Mar 2007 Location: Guelph Posts: 550	Try reversing either the receiver power plug into the wall or if the speakers are powered as most computer speakers are, the speaker power unit plug but not both. This might cure the hum. I assume if the receiver is old it does not have a polarized or 3 plug. If it does you'd have to switch the speaker power. Another thing. adapt the 3.5mm jack to RCA as you have done and plug those jacks into the tape out jacks on the receiver...if it has any or preamp out whatever they might be called. SO you'd have RCA male to male Red and white from the receiver into a twin RCA female red and white adapter to a single 3.5mm jack. I am not saying this would cure the hum but at least all the signals would match up.

2012-05-27, 05:31 PM	#3
zachdini Rookie Join Date: May 2012 Posts: 2	Thanks for the help! I tried reversing first the speakers and then the receiver, making sure they both weren't reversed at the same time. The hum is still there and there's a faint static sound, as there was before. The reason I converted the speakers all the way to speaker wire was so that I could turn these speakers on/off and send my sound to other speakers using the receiver's A/B speaker settings. However, if you feel like going straight to RCA would get rid of the hum and improve the sound, I'll give it a try. Under "tape" my receiver has REC out and Playback. Yesterday, I saw someone in a similar situation mention that the speakers and receiver give off different voltage and someone recommended a device/adaptor that you run the setup through to correct it. I remember them saying it should cost about $20 but I can't find the thread or the name of the device. Do you know what I'm talking about?

2012-05-27, 09:05 PM	#5
timlocke Join Date: Mar 2007 Location: Guelph Posts: 550	The use of tape out ( REC) should work perfectly. That output will be a standard 1Volt output from the preamp stage of the receiver just the same as the line out socket on a computer. Note that the speakers will be on all the time and you'll have to turn them off to silence them. I am not surprised that swapping the power "polarity" ( not the correct term at all) did not work but there was a chance that a cheap power supply was leaving some ripple added to the signal. Hum in analogue audio has been a problem just about forever. I agree with 57 that most likely using the headphone jack will turn off the other speakers...which my be just what you want. Just as the TAPE out, the levels and impedance should be correct.