Damaged speaker cable:Could 2 speakers be wired to AVR via 2+ but 1- ?

Pistou

Standard Member
I have two ceiling speakers (in a bedroom). Unfortunately itappears that one speaker cable has been damaged somewhere along the routeduring the renovation works of my flat. The speaker itself has been tested bythe installer and works fine. So it looks as something has either cut partiallythe cable or a screw/nail has been put inside. It is not possible to determinewhere the cable has been damaged as it goes a long way throughwalls/ceiling. However only oneconductor of the speaker cable has been damaged.

Could I bypass the damaged conductor by using the undamagedconductor for the positive and then wire the negative connector of this speakerto the other ceiling speaker (which speaker cable is not damaged) so to as toshare its negative conductor? Hence there will be 2 positive conductors foreach speaker, but one shared negative conductor. Could I still get Stereoaudio? Will the AVR negative connector be overloaded? Is there a piece ofequipment to be used to potentially solve this problem?

For reference, the AVR is a Yamaha RX-V373.

Many thanks in advance for your help!

Pistou
 

Rich9600

Active Member
No. If they are two different channels they will be receiving different signals at different times, so this would not work, and could be potentially damaging to the amp.
 
No. If they are two different channels they will be receiving different signals at different times, so this would not work, and could be potentially damaging to the amp.

The above would be true for many much older amplifiers (with valves or early transistorised output stages), but not for modern amps.

It's correct that there will be different signals on the +ve connections to the 2 speakers, but the -ve connections for the 2 speakers are actually connected together inside the amplifier, so you CAN just use the 1 good negative cable to connect both of these speakers back to the amplifier, i.e. the multiple -ve speaker connectors on a stereo, or multi-channel amp are purely for convenience of 'normal' wiring.

Admittedly, the 1 negative cable will be carrying the return current for both channels, but this should not cause any serious problems, other than a slight volume loss.
 

spyder viewer

Distinguished Member
If the outputs of the amplifier are fully decoupled then yes but if they are direct coupled, then there may be a finite offset in the negatives of each output. How can you prove that only one conductor has been damaged?
 

Pistou

Standard Member
Thanks all for your comments.
The installer has tested the cable and found out that one conductor was no longer carrying the signal, but the other yes. They've in fact been able to connect the 2 -ve of each speakers and connect x1 -ve to the AVR which negative connectors share a common ground. So it works.
 
If the outputs of the amplifier ... are direct coupled, then there may be a finite offset in the negatives of each output.

Coupling is only associated with the active components of an amplifier, and thus, only the Positive speaker terminals; so any uncorrected DC offset would be on those terminals.

I've looked at the circuit diagram for the OP's actual amp, and can see that the speaker negatives are connected directly together within the amplifier (at a so-called 'star-point earth'), so there cannot possibly be any '... finite offset in the negatives of each output'.

Therefore, there is no problem with the OP using just the 1 negative connection to the 2 speakers - as he has actually (and successfully) done now !
 

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