MOSFETs for Zen amp

[Thoth]

I recently aquired quite a few (24 each) 2SK135 and 2SJ50 MOSFETs. These complementary MOSFETs were made by Hitachi, and I've heard that they are excellent for audio use. Is it possible to use these in the Zen amp? Can I run 4 of these in parallel and bump the voltage for 20W output?

Thanks.

 

[ding]

Thoth

I am certainly no expert on this matter but a little while ago I was seeking advice on the very same thing. Unfortunately the 2SK135/2SJ50 mosfets only have Id currents of 8/-8 Amps. I believe Nelson calls for a 12A minimum requirement in his article. I think the minimum requirement is as follows

Voltage > 40V
Current > 12A
Power > 125W

The voltage requirement in the original article was 100V (I think). I have read elsewhere on several occasions that lowering the mosfet voltage improves distortion figures.

I don't know of the effects of running fets in parallel in the ZEN circuit, sorry.

Dan

 

[Thoth]

The information I was able to dredge up on these devices (www.infomaniak.ch/~bonavolt/images/2sk135j50.gif) is:

Voltage: 160V
Current: 7A
Power: 100W

I saw the comment about lower voltage MOSFETS improving the sound (ZEN Revisited). This was in reference to the IRFP140/240 devices. The reason cited was that the lower voltage units had a higher transconductance (IRFP140 - 14, IRFP240 - 10). Unfortunately, I don't know the transconductance for the 2SK135/2SJ50 devices. I think this would be the primary determining factor in how well they'd work in a ZEN amp.

Oh well, maybe I can use these as the output stage for a BIG poweramp for a subwoofer.

 

[peter pkcc]

Thoth,

By any chance you can let me know where you purchased these 2SK135/2SJ50 devices? My old Hafler uses similar transistors in it's output stage and they are getting older and in need of replacement.

Peter