Trace AH500 and the rare Mosfets

[drewl]

So, this is a big ugly box with stuff bolted inside.

Two channel bass amp, one channel is bad, it has the rare and mysterious 2SK135/2SJ50 metal can T03 mosfets which are quite rare.

Anyone find a decent source for these, (if you did you're probably not going to tell anyone)
Soooo.... has anyone been able to install modern flat pack style ones in here?
The way it's laid out with the heatsink, the only way would be to flip the FETS upside down.

I've had success using IRFP240/9240's as replacements, just need to find a way to make them fit.

Or pay ~ $25/pair plus another ~ $25/pair shipping from the far east for originals.

[Enzo]

"Originals?" HAH!


I remember paying $30 apiece for those transistors 20 years ago, when some folks still had a few. $25 a pair today would be a gift. Or fakes.

I have a four channel PA full of them, and I am hoarding it as a source for the things.

[Steve Conner]

They are somewhat "Unobtanium". Try the BUZ901 and BUZ906 as replacements, available from Newark. You can get similar devices branded "Exicon" from Profusion in the UK.

The IRFP240/9240 might work for a while, but they might go into thermal runaway and die.

[Jazz P Bass]

Exicon manufactures the replacement.
Buz900 & 905.
2SK134 2SJ49 BUZ900 BUZ905 ECF10N16 ECF10P16 Exicon Set | eBay

[drewl]

Yeah, I'd hoard them if I had them too!

Anyway, I found BUZ901 and 906's at a decent price.
Any rebiasing needed?
If so shouldn't be too hard.

Thanks.

[Jazz P Bass]

Here is a nice rundown on lateral mosfets from DIYAudio.
Link: Audio (Lateral) MOSFET's for Class AB - Overview, P-Spice URL's - diyAudio

[Ted]

I've tried IRFP240/9240s in an AH300.
They DO go into thermal runaway and die.