P-channel mosfets for Aleph


2000-11-24 12:02 am
Yes, an ALEPH can be build using P Channel mosfets. At least
I do not see to much problems.
To illustrate this I made an example schematic of an ALEPH 3
with P Channel IRFP9140. As you can see you need to change
the input stage a little. (i.e. use n-channel IRF610).
I simulated this circuit, and it behaves very similar to the
original ALEPH 3.

I hope this helps you a little.


  • aleph1_pmos.zip
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2000-11-24 12:02 am
Just some examples...

Looking at the datasheets

For IRFP240
Ciss 1300 pF
Gfs 6,9 S min. pulse

For IRFP9140
Ciss 1400 pF
Gfs 6,2 S min. pulse

Please check the curves!

So, N-channel are only slightly better, but P-channel will not
make a terrible amplifier.

I remember their use in the original ZEN.
I think they are used in the X series as well.
Nelson Pass said:
I made an Aleph with 9240's just for the hell of it about
8 years ago. I didn't hear or measure much difference,
but the lower price and better availability of the N channels
made it a moot point.

I know the Pchannel Hitachis have a failure mechanism (precisely what I don't know) that the Nchannels lack....Seems maybe the IR Pchannels are 1rst to blow also ?????????????????