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Old 2nd August 2003, 06:06 PM   #1
Netlist is offline Netlist  Belgium
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Default John Bowers Active 1

Donít know where to post this; it is both solid state and speakers.
Anyway the problem is about transistors so here I go:

Got a pair of these speakers from a customer, brought in for repair years ago.
After telling him the price for repair, I never saw him again.
Years have past now and I just decided to try to fix those speakers for myself.
The name says Active, which means they are powered speakers.
Picture 21-23 at
are about the only pics I could find on the net.
The mosfet amplifier has 2sj99 and 2sk343 devices in it.
Possible replacements could be 2SJ82/83, 2SK226/227 but they are also not easily available and their pin out is different.
So, the question is obvious:
Would anyone here on the forum be able to point me in the right direction (replacements) or maybe someone has those fets lying around and is willing to sell them.
I need two of each.

Many thanks

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Old 28th December 2003, 09:00 PM   #2
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Location: Ruhrgebiet
where do you live? I'm from Germany.
Would you like to buy a brandnew bass-amplifier for your active1 (210Ä)?
Or 2 pairs of transistors (K344 and J100) for 70Ä.
Kind Regards Rainer (
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Old 1st December 2008, 05:13 AM   #3
ntguy is offline ntguy  Canada
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Are these still available? I'm interest. Thanks!
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Old 13th July 2010, 01:26 PM   #4
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Smile john bowers active 1

From my pair of speakers a few tips.
One of them became unstable, and switched itself on and off intermittently.
Problem was in the regulator on the filter board - both capacitors had dried out, and read zero mfd - they are very close to both high power resistors and hot running transistors.
Try changing them to high temp working ones.

The other thing I noted is that the HF mosfet amp does produce a small dc voltage across its output - not a good idea for feeding a tweeter, and a fault condition could write it off.
I have located some 2sk343 transistors, and if anyone would like to share a part order ( 10 is the minimum I can order) please shout !
I also think that I have found modern day more robust mosfets to change the 2sk343 and 2sj99's.
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Old 11th August 2010, 08:37 AM   #5
rolleye is offline rolleye  United Kingdom
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I might be interested in these transistors for a pair of JB Active 1's, what price are they?
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