Sunday, May 18, 2008

DIY HiFi Speaker Cables

When buying a Home Theater system, your saleman might suggest to shell out ever more money for gold-plated monster speaker cables. This sounds like a reasonable idea since anyone can imagine that skinny wires between the amplifier and speaker might degrade the sound. Moreover, there is no certification for audio amplifier wiring as there is for say, electrical wiring. So, when in doubt, more is better, as any audiophile knows.

But how does one know that these fancy cables will actually provide a significant benefit relative to the cost? Suppose there is a limitation imposed within the amplifier that moots any improvement provided by external wiring?

When purchasing Focal 714v speakers at my friendly neighborhood stereo store, I noticed the salesman was using cables large enough to boost car batteries. On the other hand, my home stereo was using lamp cord. So I disassembled my JVC RX-660vbk to inspect the signal path and remove six years of cat dander. I was dismayed to find the speaker signal path was one foot of 24awg ribbon cable, two speaker switches, and a relay. Moreover, it was a single sided circuit board with several segments of 20awg wire jumpers between the relay and the power transistors. If the amp was run at it's rated power of 400w, the ribbon cable would probably melt.

I would not be surprised to see similiar designs in other "mass-market" audio equipment. The connections are on back of a cabinet, the controls are on the front. Good designers ensure that connections in signal path are robust. Audiophiles invest significant dollars to get this quality. Mass marketers cut corners hoping that customers won't notice subtle differences.

Instead of expensive cables, I suggest to buy measured lengths of 12awg speaker wire from Home Depot or anywhere. Strip one half-inch of insulation from each end. Optionally, dab solder on the last one-quarter inch of bare wire to prevent separation of the strands. Gold plating to prevent corrosion of the wires might be needed on your yacht but not in the benign environment of your home. Just in case, disconnect and reconnect the wires every six months to make a new metal to metal contact.

P.S. 12awg wire can handle 40amps, 24awg can take maybe 3amps. It certainly should not be used in audio speaker circuits.