Re: LF: W1VD amp help - more waveforms

[N1BUG <paul@n1bug.com>]

Hello again Chris,

> What's   the   vertical   board  in  the  end of the case? If it's the
> multiplier  I  am  not qualified to say what having in the same box as
> all that RF might be, but i would have some concerns.

Yes that's what it is and yes that may be a problem. However at the
moment for testing and troubleshooting elsewhere, I'm not using that
board. There are no wires whatsoever connected to it.

> I would mount the driver board, shortened if necessary,

The driver board I'm using is as small/short as it gets by me
building it. ;-) I had a devil of a time getting everything onto
this size board!

> I'd be tempted to apply full voltage and see what happens

Not yet. My drain spikes are about 64V with 13V supply, 130V with
25V supply, give or take a couple volts in each case. It might be OK
(just) at 37.5V but I'm fairly sure 50V would kill these FETs quite
efficiently.

If/when I blow these FETs this gets moved forward into next year's
project queue. I have just one spare FET. And sadly, one can't even
get these 'good' ones in the TO-247 package any more. When these
die, which we all know will happen sooner or later I will be forced,
albeit most reluctantly, to switch to the less desirable and fiddly
little TO-220 package. Grr!

I've got to get away from this thing for a while. I'll take another
look at it tomorrow.

Paul