engeng Posted February 22, 2004 Share Posted February 22, 2004 I'm trying to diagnose an issue with my HK AVR520 - it randomly shuts down (self-protect mode, I think) after 15- 60 minutes of use. When re-powered on it runs for hours, no problem. It happens about 75% of the time I use the reciever. I measured the resistance of the speakers to estimate the impedance and was surprised the value was only 3.7 ohms. I also checked my newer RS3-II's and they were also 3.7 ohms. Both manuals state 8 Ohm nominal impedance. Of course the HK manual states 8 ohm impendence is required. Any ideas other than taking the HK to the repair center (HK's recomendation)? Quote Link to comment Share on other sites More sharing options...
jerohm Posted February 23, 2004 Share Posted February 23, 2004 3.7 is the correct Re of the woofer (k-10-k) and if you measure across the speaker terminals, that is most likely the value you are going to get. The impedance varies with frequency, so 'nominally'speaking, 8 may very well be correct. I would make absolute sure that your speaker cables are not intermittently shorting (which may sound unlikely, but isn't all that rare) under certain vibration conditions. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted February 23, 2004 Share Posted February 23, 2004 What was measured was the DC resistance of the speaker, and not the ac reactance portion of the impedance. An 8 ohm speaker is never 8 ohms, as the impedance is constantly changing with frequency. This is only a nominal rating. Quote Link to comment Share on other sites More sharing options...
engeng Posted February 23, 2004 Author Share Posted February 23, 2004 Thanks for the responses - I realize the resistance via DVM wasn't an accurate measure of the impedance, but thought it would generate a closer value... This weekend I replaced very old 16ga wires with new 14 ga with banana plug terminals to eliminate them as the possible source of the issue. The HK still cuts out. Time to take it in before the warranty expires! Quote Link to comment Share on other sites More sharing options...
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