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Subwoofer causes noise from the speakers

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conqueeftador

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If there is a problem with one of the subs RCAs, what is the likelyhood of both subs being faulty in the same way?

What are the differences in an analogue RCA and digital audio RCA?
 

antcollinet

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If there is a problem with one of the subs RCAs, what is the likelyhood of both subs being faulty in the same way?

What are the differences in an analogue RCA and digital audio RCA?
Charcteristic impedance - but that cannot cause noise, and won't do much at audio frequencies. Which QED cable do you have?
 

Zek

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Maybe the RCA connectors on the QED cable have bad contacts.
 
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conqueeftador

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One is an older QED Qnect2 "balanced?" low level signal cable. Another is the recent QED Performance Audio.
 
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freemansteve

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Balanced? I'm already worried by this, as I doubt the amp or subs use balanced I/O - you may have a wire in the cabling that is un-terminated and acting as an antenna ....

Can you just clarify whether changing the RCA cabling between amp and subs (or between DAC and Amp) to some cheap cable from Amazon has an effect?
 

antcollinet

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I think both your QED cables have an electrostatic screen connected at only one end. I'm wondering if that can be doing something weird with noise pickup. Are the cables "directional".



Electrostatic Screen​

Provides immunity from external high voltage noise signals. Only connected at the source equipment end hence the directionality arrows on the cable jacket.



I'd agree with the suggestion to try some bog standard RCA connectors.
 
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conqueeftador

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Both have some very small arrows I have failed to notice previously, although assuming the arrow points away from the source means amp 2 was wire properly but still made noise.

No idea how an RCA can be balanced for no balanced use, but there we are.

Generally found the cheaper cables to bee hit and miss as to quality and soldering hence buying these, no issues untill now.
 
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Both have some very small arrows I have failed to notice previously, although assuming the arrow points away from the source means amp 2 was wire properly but still made noise.

No idea how an RCA can be balanced for no balanced use, but there we are.

Generally found the cheaper cables to bee hit and miss as to quality and soldering hence buying these, no issues untill now.

Please forgive the blunt question ... but did your setup ever work right... or have you been having this problem all along?

One explanation could be a DC output on the amp's "sub out" jacks.
Another could be bad caps on the sub-woofer inputs.
Still another could be some kind of local interference getting into the amps.

There's a million variables here ...
I would start by pulling the whole thing down. Testing each RCA cable and checking voltages on all outputs and inputs. Then I would start building it back up one piece at a time starting with your speakers, then one sub then the other, then the amps, then your sources. At some point in the process adding a new device will start the problem going... and there's your bad actor.
 
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I'd agree with the suggestion to try some bog standard RCA connectors.

I'll throw down on that suggestion as well ...
Amazon Basics RCA cables.
Monoprice 16ga OFC speaker wire.

It's almost always the "fancy stuff" that causes the problems.
 

Chrispy

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LOL gotta love the directional rca to rca cables.....
 

clearnfc

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Both have some very small arrows I have failed to notice previously, although assuming the arrow points away from the source means amp 2 was wire properly but still made noise.

No idea how an RCA can be balanced for no balanced use, but there we are.

Generally found the cheaper cables to bee hit and miss as to quality and soldering hence buying these, no issues untill now.

Might be wire. Try changing the cables just in case it could be due to cable.

As for those arrows, just for the shielding... What happens is that the foil/braided shield is only soldered on 1 side of the cable. The arrow will allow you to know which side the soldering is on. But its not a critical issue and even if you connect the wrong way, it should not cause any problem.
 
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