hmm.. help with mosfets

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Ok.. I'll start this off with the fact that I don't know much about solid state at all.. im a tube person..

so anyways, I got some power mosfets. I know they are complimentry pair, but have no idea how to wire that (as I dont know SS).

anywyas here is the pair:

What i know of them is that they are 120v, 8A, 80w dissipation. I can't find a datasheet though :(

there is also two gain transistors per channel.
both are:
K1420 (might be 2SK1420)

Anyone want to help me figure out how to wire the output stage? ???

Thanks, :D
Actually, the 2SB/2SD transistors are BJTs. You can figure out the leads using a Multimeter with with Hfe reading. As these dissipate 80W I'm assuming that they are TO-220 (?) with the most common pinnout looking at the front being: Base, Collector, Emitter.

As for the 2SK1420, This is a MOSFET:

Ultra High Speed Switching
60V 15A 30W in a TO-220 Most common pinnout: Gate, Drain, Source.

As for wiring the OPS, are you working off of a schematic, or are you trying to work out a design of your own? More info is needed as to what you are trying to do.

Oh okay, thanks :)

I don't have any schematic, but I would like to make a power amp with this (perhaps integrated). I'll probably end up using it for a sub in my room.. but might use it on fullranges as well.

any information as how to wire this would be great :)

Thanks, Mark

oh yes, they are B-C-E, and TO-220 (well a little bigger than normal to-220's.. i'm not sure what it is called.)

I can probably run it off a preamp, so just power stage is okay for now :)
Prolly TO-247 or TO-3P. these are bigger than TO-220's and usually can handle up to 300W or so.

The output that you would create from these would then be a Quasicomplimentary Mosfet Design, using the BJT's as driver transistors and the MOSFETs for the Power. There is a small thread on this. It references the Holton N-channel amp, however the OPS is a little more complicated than need be I personally think. This is assuming that you are looking to build a class B or Class AB OPS.

If on the off chance that you want a class A amp from this, then a Zen might be a good choice by just using the MOSFETs. Of course the circuit would need some tweeking to fit these particular MOSFETs.

What were you thinking of for a front end?

I was thinking I might drive it with a tube.. or something like that.

the amp that I pulled these from, the D718 & B688 were used as output, one of each per channel. (touted as 100w per channel, but I assume that was a over-rating)

So I basically wanted to see how to use these as power stage, in complementary (what class is this? I'm used to tubes..)

so for now I'm just trying to get a basic idea of how transistor output works (with a NPN & PNP pair).

A Hybred :p I like that. There seems to be some debate about the quasi-MOSFET thing, but it can be done. Seems that most use Complmentary N and P channel devices for full complimentary as opposed to Quasi. I think that that would be difficult in your situation as I would guess that a P channel compliment doesn't exist for that particular 2SK device. But, if you are good at disecting schematics
would be a good start. This would be a Class B or AB (havn't read the article). Another Idea would be to treat the Mosfets as tubes using transformer coupling setting up a class B PP stage. I've just recently read an old book on transistors that talks about doing this. I'm not familiar with tubes and don't really have audio tranfos laying around to play with, but it might be another idea. I think the "cycletron with n-channel mosfet" thread may cover some of this, but again I havn't read most of it. Hope that helps, it's bed time for me, and keep me posted (I have a bunch of NPN power BJTs that are screaming for something like this).


P.S. I have and old Radio Shack 40W PA amp that uses 2 NPNs and a transformer in the output, can't find a schematic and I use the thing for a monitor so I have yet to tear it down enough to see the exact topology, but maybe soon :rolleyes:

What was the Amp that these came out of? Do you have or have you looked for a schematic for it?
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