lsim 705 fried crossover what kind of upgrades should I do.
jghglofer
Posts: 100
I notice that one of my 705's was sounding a little off and crackly. after some investigation. I found the crossover has some burnt components. my question is i have this apart and it needs replaced. I need help on what upgrade I need to do. Polk want 200 for a new crossover. that's the easy fix. but if I can improve the crossover then that's the way I want to go. TIA
Answers
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Looks like you had them at 11 for an extended period. Appears the resistor got rocket hot and may have emoliated the cap as well.
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Must've been a hell of a NYE party!
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whatever you decide dont mount the resistor next to the cap...
I thought Polk would have learned with the LSi... :-p- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
Incidents like this just remind us of where all that power it takes to run modern loudspeakers goes
Not to sound, but to heat. Yay. 
OK enough grumpy old man...
On topic. it's kosher
to mount the power resistor offset from the board. Probably a good idea. Heat is the enemy.
The other option is, of course, power resistors like this -- but, again, give 'em a little room to breathe.
Many of these (like this Dale) are designed to be mounted on a heatsink.
Outboard XOs aren't a bad idea, either. Let 'em respire!
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As a not-entirely-unrelated aside: I had a cathode bypass cap pop in my single-ended 2A3 amp due to its proximity to the cathode resistor. When I replaced the cap(s), I separated them from those power resistors.
