sleazymamba
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- Joined
- May 24, 2022
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Hi,
I have recently purchased a Wharfedale SW-150 subwoofer which is being driven by my old Technics SU-A700 MK3 amp. Very happy with it.
However I am getting a pronounced and clearly noticeable mains hum when the Technics amp is powered off.
I am considering getting some shielded speaker cables with a shield wrap that could be earthed to ground, in the hope that this might eliminate or reduce the induced current in the conductors. eg https://www.audiophonics.fr/en/cabl...e-ofc-2x25mm-frnc-shielded-o-83mm-p-9922.html
Does anyone have any experience of this approach, and it it likely to work ? Anyone got a better idea ?
The long term solution is to save up for a new amp with sub out, but that isn't on the cards for a while.
Need help.
Thanks.
I have recently purchased a Wharfedale SW-150 subwoofer which is being driven by my old Technics SU-A700 MK3 amp. Very happy with it.
However I am getting a pronounced and clearly noticeable mains hum when the Technics amp is powered off.
- The subwoofer is connected from my amplifier “B” speaker output to the speaker level input connections on the subwoofer. I use 2.5sq mm pure copper speaker cables and banana plugs. Both left and right channels are connected.
I do not have sub out on my amp. - The hum stops immediately when the amplifier is powered up, even if no source is playing. I guess the amp is grounding the negative cables but only when switched on.
- The hum still occurs if I remove the speaker cables completely from the back of the amplifier.
- The hum stops if I remove the speaker cables from the back of the subwoofer.
- This is clearly an induced current in the connecting wires which, being speaker cables, are unshielded. I have tried moving them away from any mains cables and using a different (UK) mains socket for mains power but it persists.
I am considering getting some shielded speaker cables with a shield wrap that could be earthed to ground, in the hope that this might eliminate or reduce the induced current in the conductors. eg https://www.audiophonics.fr/en/cabl...e-ofc-2x25mm-frnc-shielded-o-83mm-p-9922.html
Does anyone have any experience of this approach, and it it likely to work ? Anyone got a better idea ?
The long term solution is to save up for a new amp with sub out, but that isn't on the cards for a while.
Need help.
Thanks.