NAP / 500 / Loud Speaker - Capacitance and Inductance

Hi-Fi Corner
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Wouldn’t it be great if there was no inductance of capacitance, and then everything would become a known known. Fortunately there are frequencies where this happens (the LCR resonance)…which for the NACA5 is circa 710MHz.

BTW…the nefarious effects of certain speaker cables are more than an urban myth. A friend of mine hooked up some 20 foot lengths of Cardas Golden Reference speaker cables to his 500. That then proceeded run EXTREMELY hot (you could not touch the heatsinks without fear of burns) and the sound went decidely off. The combination of high capacitance and low inductance cheerfully tipped the 500 into ultrasonic (possibly RF?) oscillations. Had he not swiftly removed the offending cables, his 500 would not have survived very long. Running this amp with exactly the wrong cables is like running an engine without oil…it will run (badly)…but not for very long before it self-immolates.

1 Like
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I managed to do something similar with my NAP250.2. I had Kimber 8TC on a big tube amp I was running at the time and so wanted to see how it worked with the NAP250. It got hot - very hot. And the sound was, as you say Ron, decidely off. I quickly switched off just in case the worst happened (although I guess the thermal trip would activate). The worst thing was that after that little experiment, I was never convinced that the NAP250 sounded quite right. When I did eventually get around to getting it looked at by the service dept., it came back sounding much, much better.

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