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homemade cables and blown tweeters

I recently made a set of 25 foot cables to send a feed from the normal output of a Parasound 850 pre-amp to the low level input on an Earthquake sub. I terminated both ends of the 12 AWG monster cable with gold RCA and solder.
Within a week i blew tweeters in some 22 year old speakers. Thinking that it was age i retired them and bought some new Paradigms. Within a week those tweeters are blown. IT could be the power amp???, Pre amp?? but i ran those in a config using the sub and high level inputs for 2 months w/o a problem? I would like to use the sub, but am unsure if it is the sub, or the cables. any ideas??
Are interconnects not to be 12 awg, copper? Any help appreciated
thanks
John
jonniem
porziob
316 posts
 
Your IC recipe spells disaster-12 ga. is entirely unsuitable.
mlsstl
1,436 posts
 
There is a fair chance that someplace along the line you have acquired a high frequency oscillation that is feeding enough power to blow the tweeters. Sounds like it may be beyond your limit of hearing. It would be very interesting to hook an oscilloscope or frequency analyzer to your speaker leads and see what is there.

The source could be your cable. You say this is Monster cable, but is it shielded? A 25 foot run at preamp line output levels could be picking up RFI and feeding it back to the amp section that powers the speakers with tweeters.

There could also be another reason for this oscillation. Whatever it is, though, you need to find out before you lose another set of tweeters. This is best accomplished with some test equipment, so see if your dealer can help you.
jonniem OP
3 posts
 
great explanation
thanks so much
should have purchased those interconnects instead of making my own.
Not shielded, just number 12 zip cord.............
I will replace the tweeters on the paradigma and
run w/o sub till i get my courage up and buy some quality interconnects.
john ,m
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