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View Full Version : balanced connection to a 4 channel amp...will this work



davidismynaim
23-09-2012, 21:32
Hi everyone, looking for someone with more experience than me as to an idea I have with some recently acquired HiFi.

I have an M-DAC which has the option of balanced output via XLR. I have just bought a beast of a SS amp off ebay - it is a DBX BX3 4 channel power amp.

It has 2x stereo phono inputs, with 3 modes, 4 way, 3 way and bridged 2 way. Someone suggested I could make up special XLR to 2 phono cables. Hot to one phono, cold to the other, both sharing the earth. These 2 cables could then be used as the input with the amp in 4 way mode. connecting the speakers to only the red terminals.

I have never used balanced connections and this is pushing my knowledge to the limit. But as I understand this arrangement, the speaker would see the differential between the +ve and -ve polarity on the two speaker posts and this would cancel out any common noise. Have I got this right and does this sound like a sensible plan?

The alternative is to switch the amp into bridge mode and connect up using a single set of unbalanced phono cables.

thanks for any help here...

PS I have just bought a pair of Yamaha NS1000M (a speaker I have wanted for over 35 years, so felt it was about time to scratch that itch!) Having the tired black cabinets re-veneered in light oak... If the Balanced arrangement works it will be about 300W amp, so I am planning to use 20db attenuators on the back of the M-DAC, and the amp has gain control too, so should be ok?

Any thoughts...

Reid Malenfant
23-09-2012, 22:08
Yes, from your description it sounds like as long as you leave the amp in 4 way mode, & feed the balanced output of the DAC to the centre pins of the phono connectors with a suitable cable, you'll get a bridged two channel amp :)

As you say, use the positive outputs on all channels.

You'll need to take note of which channel the hot or positive wire from the DAC is connected to on each output of the DAC, as this will be the channel to connect the positive of the speakers to to keep them in phase ;)


Sounds like some fun is about to happen :D