Definitive Technology BP20 Mod Thread
Comments
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Soooo... I am shooting from the hip
Those mox resistors, if the coating wears off can become conductive to their surroundings. You have them tight to the boards and overlapping some traces, have you created a short?- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit. -
Didn’t know that about the resistors. They are new so shouldn’t be an issue but I’ll check and raise them up enough to clear.
Thanks for your help guys, I really appreciate it. I’m going to put one of the speakers back together and try it out. I’ll let you know ! -
Well, it all works perfectly, so i was worried about nothing.
Learned a few things though, so it was worth it.
Thanks again for your help Guys !! -
Of course now im wondering if there is any value in replacing the factory air core inductor in the tweeter circuit. With the physical size limitation on this board, are any gains worth the effort ? I have reasonable quality Clarity cap and Jantzen resistors with a crap inductor. Im not sure it even has a value stamped on it.
Is the inductor of much importance?
What do you think ? -
The tweeter inductor is ok really. The woofers probably use a junk iron core that is in line with the woofers though that would definitely be beneficial to replace.- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Wow, glad i asked. Its probably a given that the iron core in the woofer circuit is a low quality component. Its replacement cannot be physically much bigger though if i stay with its current location. That probably limits me severely, without going to a secondary board, or spacing a board above my resistors. Hmmm....Do you have any suggestions Sir ?
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You can use two smaller inductors in series to make one larger inductor but try to make sure the two are the same size.- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Thats an idea, but placement might be even more of a problem. I read on a GR research page about inductor placement. Ill see if i can find it.
https://gr-research.com/inductors/
The bottom of this page shows some dont dos ! -
Indeed, you can also remote mount it- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Agreed. It might be the only way. If i put a bridge board above the resistors, ill have room for a decent coil laying down, but it will essentially stack on top of the tweeters air coil with about 1/2" between them. Probably not good !
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I dont suppose you documented the value of the factory iron core inductor from one of your builds ?
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Can't say I ever replaced the inductor on the bp20, if I did I unfortunately do not have that in my records- Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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Ok. Well thanks for your help on this and I appreciate you letting me bounce ideas off you.
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I’ve owned BP20s since the 90s (original owner) and I’m about to get them back out to mod them. In the past I modded by simply unplugging the rear top driver and tweeter, so that I could get a more focused soundstage, and it worked for me. Now I’m interested in modding the tweeter with an AMT or beryllium design. Does anybody have the crossover frequencies or schematics or og manuals? Thanks!
