Cable "burning": Real or VooDoo ???

Sean - I think you are right that the output voltage of the amp will be more regulated with the small wire. However, I believe the voltage at the speaker terminals will not. Instead of small wire just imagine that an 8 ohm speaker has an 8 ohm resistor in series with it. Now half the amplifiers output voltage will be dropped across the speaker. AS the output impedance of the speaker falls less voltage is dropped across the speaker. As the speaker impedance rises the voltage across the speaker increases. The speaker is no longer connected to a voltage source. As seen by the speaker the 8 ohm resistor trashes the damping factor of the amp.

Low impedance loads are a problem for all amps that are not designed for them. Even springing power supplies optimized for 8 ohms will deliver enough current to smoke output devices if the impedance falls low enough. The designer either has to use more output devices and drivers or provide an effective protection circuit that limits the current vs. time the output sees.

Frap - I didn't mention the connection between damping factor and feedback. Basically, the more feedback the higher the damping factor. SS amps have higher damping factors and lower distortion because more feedback can be used. It is difficult to wrap much feedback around a tube amp because of the output transformer. Output transformers are a designer's nightmare. One of the transformer's problems is the unavoidably large phase shift at low frequencies. This will turn negative feedback into positive feedback if very much is used.

Steve, mostly all of the mid to late 70s high power SS superamps used tons of negative feedback. Whatever benefits derived from excessive amounts of it,were all negated by the God awful sonic results. The spec sheets were always the same; i.e. incredibly low static distortion figures at very high power...damping factors up in the hundreds!!! and low slew rates (remember when slew rates were the most important specs?). The tank amplifier that Sean was referring to, was, for sure, the Mark Levinson ML-2. There was simply no better made SS amp in that era.

Steve, your example takes things to an extreme. How much "small gauge" wire would you have to run to increase the line loss to the level that you mentioned ??? I took and measured appr 20' of 21 gauge wire. This would be equivalent to a 10' run of cable to and from the speaker. Series resistance was less than 0.3 ohm. While a smaller wire would be higher in resistance and a longer run would also contribute to this, it would take a LOT of wire to produce even just a FEW ohms of resistive loss.

Even with that in mind, i'm NOT discounting your theory that various speaker cables DO alter the load that the amp sees. As such, the amp CAN respond differently to specific impedance combinations that it is presented with due to different speaker / speaker cables / cable lengths required in various installations. As such, you have only helped me to prove that wires CAN sound different and ARE completely system dependent due to the stability of the circuit driving it.

THANKS for the help in clarifying this situation, as i never knew you had it in ya..... : ) Sean
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Sean - I used the 8 ohms just to make the example easier to think about. I'm not sure but a damping factor of one may be similar to the results with an 8 ohm resistor. You won't get any naysaying from me about phenomena that can alter the frequency response.

How is it then that i remember you as being one of the "wire is wire" crowd ? Am i mistaken ? Sean
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