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Super Blowing Speakers/Arching Output X?

1/6/2000 6:48 PM
Curtis Laur	Super Blowing Speakers/Arching Output X? I Just got a Fender Super Amp in for repair that has been to a couple of repair shops around LA. It is the newer model with channel switching. The circuit board covers the whole top of the amp making it hard to work on. It has blown the 2 right speakers on the 3 last gigs it was used on! The speakers are wired in series/parallel (right for this model super) and it keeps blowing the two speaker wired to the negative side. So it blew the two stock speakers. Two Mojo's HD Alnico were installed. It blew those. It was taken to another tech who installed 2 more Mojo's but rotated them so the Mojo's were both on top. Checked the amp out and found no problems. On the next gig he blew the two right speakers again (1 Mojo & 1 stock Fender). The guy does play very loud. I've talked to some techs and the theorys are that DC is getting to the speakers somehow and two speakers are blowing before it can get to the other two that are in series after them. I looked around where the feedback loop was coming into the circuit board and saw no signs of arching. I also check out the output transformer with a signal generater and a current meter. Did the math and got 5000 ohm into 8 ohms. Seems fine there. Could the output transformer be arching or is this guy just playing too loud? It does seem strange that he would be blowing the same two speakers every time. Any help would be appreciated. Thanks, Curtis.

1/6/2000 6:48 PM

Curtis Laur

Super Blowing Speakers/Arching Output X?

I Just got a Fender Super Amp in for repair that has been to a couple of repair shops around LA. It is the newer model with channel switching. The circuit board covers the whole top of the amp making it hard to work on. It has blown the 2 right speakers on the 3 last gigs it was used on! The speakers are wired in series/parallel (right for this model super) and it keeps blowing the two speaker wired to the negative side. So it blew the two stock speakers. Two Mojo's HD Alnico were installed. It blew those. It was taken to another tech who installed 2 more Mojo's but rotated them so the Mojo's were both on top. Checked the amp out and found no problems. On the next gig he blew the two right speakers again (1 Mojo & 1 stock Fender). The guy does play very loud. I've talked to some techs and the theorys are that DC is getting to the speakers somehow and two speakers are blowing before it can get to the other two that are in series after them.
I looked around where the feedback loop was coming into the circuit board and saw no signs of arching. I also check out the output transformer with a signal generater and a current meter. Did the math and got 5000 ohm into 8 ohms. Seems fine there. Could the output transformer be arching or is this guy just playing too loud? It does seem strange that he would be blowing the same two speakers every time. Any help would be appreciated. Thanks, Curtis.

Replies:

Bird Dog I have never heard of this situatio... -- 1/7/2000 4:25 AM
Nate S. It may be worth hipot testing the t... -- 1/7/2000 5:25 PM
JB To test this sort of situation on a... -- 1/11/2000 7:08 PM