Can speaker cables damage amplifiers?

E-mail response from Krell is that there are no problems using Transparent cables with their amps. Awaiting response from Tansparent, too. Incidentally, I still do not know what is meant by "oscillation".

Nelson Pass' 1980 article on speaker cables mentions oscillation among other things. Find it at http://www.passlabs.com/spkrcabl.htm Here is an except from page 3: "When a wave travelling down a length of cable reaches the end of the cable, it will do one of three things depending on the impedance of the load. If there is a high impedance load, so that ZL, > Zc, the load wil reflect energy positively back down the cable to reappear at the source Fig. 9). If the load impedance is less than the characteristic impedance of the cable, the wave is reflected back negatively; and if ZL = Zo, then the wave is fully absorbed and none is reflected." Good luck!

Well, I don't know what it means in this case (common usage), but I can tell you what it means in layman-engineering terms. Take Rockvirgo's email, the part about the wave being reflected back negatively. If the power amp has a feedback loop, it'll see that reflection, and try to correct for it. The feedback loop is fast -- but not instantaneous. Depending on the signal, the reflection, and the speed of the feedback loop, the amp will just never get the output right. First it'll try to push the power in one direction, overshoot and go back the other way. If things get really bad (you get some resonance) the amp can diverge wildly from the intended signal. But, if you have a reasonably talented person designing the amp and feedback loop, this won't happen -- at least at audible frequencies. Maybe this is why rumor has it that high bandwidth amps can be more prone to this effect? It's been a long time since I've done any engineer stuff -- looking back is a bit fuzzy.... Perhaps someone else can improve on this explanation.

It's my understanding that if a speaker cable's own charactersitic impedance is too low, that this is what allows the wave to reflect back into the feedback loop of the amplifier.

Oscillation? Have you ever seen the footage of that large suspension bridge that started rocking with the wind until it self-destructed? That is oscillation.