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Polyswitch resistance?


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Some of the later model Klipsch crossovers have a polyswitch tweeter protection built in.

IF I replace the polyswitches with fuses is there going to be a noticable difference in resistance.

Does the polyswitch have a SQ to it and will changing it over to a fused circuit change the SQ on the tweeter?



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A new 0.5 amp polyswitch measures about 0.6 to 0.7 ohms DCR. Old ones seem to vary around a lot on resistance often reading over 1 ohm. I replace them when I rebuild crossovers. They are supposed to react quicker than fuses to protect the tweeter better. I am not sure they are really fast enough to protect a tweeter from a big transient, but probably are quite a bit quicker than a normal fuse.

Anyway, why not just replace the polyswitches instead of going to fuses?

Bob Crites

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Polyswitches are convenience items if your prone to loud levels.....the convenience is not having t change the fuse....the cost penalty is not only the additional resistance when cool or not tripped...but once tripped and until fully cooled...the resistance is significantly higher than the initial at rest resistance.

So I can unserstand why one would want to by pass one with a fuse that cold be replaced from outside of the speaker cabinet.

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I was "playing around" with a pair of KG4s with no sound from the tweeters. The problem was in both polyswitches. I jumped the polyswitches for a quick check and tweeters came back on. I listened for a couple of minutes and the tweeters were brighter than I remembered them being on my old KG4s.

The sound from the tweeter actually sounded closer to a K-77 in the Heritage line. It seemed as if the speakers as a whole were more "alive" with better upper details. My guess was the tired polyswitches added a nasty flavor to the tone quality. Just a guess as hearing memory is not exactly accurate.

I liked the sound enough I wanted to check with the "PROs" before proceeding. If they were mine I wouldn't even worry about the fuse protection as I don't use higher volumes at all and I run a clean system with no issues to worry about blowing tweeters.


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