JBL L100a: high freq. coming through woofer

[jeremy cohen]

Hello,

I just picked up a nice but rough pair of these speakers that im going to repair. Currently the work and play music only out of the woofer and i have sprayed deoxit on the pots and twisted them quite a bit and get scratching sounds from the mids. I highly doubt these drivers are dead if the sound has been rerouted to the woofer. IF its a x-over issue what would i want to test on it? I havent taken them out yet since I just wanted to take it one step at a time and think the only way to access them is to remove the woofer which i could be wrong.


Any help would be much apprecited\
thanks all

 

[Chris Brown]

As far as the high frequencies coming out of the woofer, this is by design unfortunately. In the L100, the woofer is run full-range. The entire audio signal goes to the woofer.

Of course, that doesn't explain why the tweeters and/or crossover aren't working, but at least you shouldn't have to worry about the woofers at this point

 

[jeremy cohen]

SO weird. Well would that lean away from the x-over thought?

 

[Chris Brown]

SO weird. Well would that lean away from the x-over thought?

So you are not getting any high frequencies from the tweeters? I would try to remove the tweeters from the cabinet and test them on their own (hook the speaker wire directly to the tweeters, keep the volume low). Try this on the midrange drivers also.

 

[donprice]

Just in case you haven't looked for it...the crossover is very simple. Some would say too simple.

Borrowed from the web...

 

[swechsler]

i have sprayed deoxit on the pots and twisted them quite a bit and get scratching sounds from the mids

I've never opened up the L100 pots (I'm sure there are some of us out there who have), but if just tried to spray through the front, it's possible that the Deoxit never made it to the resistor inside. Try spraying inside with the speakers lying on their back. A better solution would be to bypass the pots entirely; just disconnect the wire from pin 3 (as shown in the schematic above) and connect it directly to the driver.

 

[HTHMAN]

A better solution would be to bypass the pots entirely; just disconnect the wire from pin 3 (as shown in the schematic above) and connect it directly to the driver.

Good idea. I was just going to suggest you jumper the pots-it would sound just like if they were turned up full.