[btl.ham-radio] HELP? - Solid State Tubes

ka9s@ihps3.UUCP (10/12/83)

	I am looking for schematic diagrams and parts sources that will
enable me to home-brew solid state tube replacements for my old DRAKE
C-line.

	Years ago I purchased four solid state tubes from Sartori Associates
Associates, W5DA and placed them in my R-4C.   They have worked fine and
I have no complaints.   At the time I corresponded with Howard Sartori about
the Solid Tubes and was informed that he could not develope a solid tube
that would perform better than the glass ( 6BA6 ) tubes.   Around the same
time Howard published an article in QST describing his Solid Tubes:

	"Solid - Tubes - a New Life for Old Designs
	by Howard J. Sartori        W5DA
	QST, April  1977,       page 45           "

Since that time technology has improved ( namely the invention of
VMOS ) and I have decided to convert as much of the old C-line to solid
state as I can.

	I wrote Mr. Sartori to see what new products might be available
and if he had any new designs he might be willing to share with me.
Howard now has developed solid state tube replacements for all the tubes
in the DRAKE C-line ( including the 6BA6 ) with the exception of the
6JB6 finals and the 12BY7A driver.    He promises to have a solid state
tube replacement for the 12BY7A some time this fall.    The bad news is
the price of the Solid Tubes ( $23.00 each ) which I find to be a little
prohibitive.    Secondly Howard is not giving out any design information
for these new Solid Tubes.

	After reading over the article he wrote years ago, it appears
that he is using some very high voltage solid state devices and I do
not know where to purchase them.   I also feel that there must be better
designs around now that VMOS devices are available.

	If any of you have the designs or parts sources I need, I would
appreciate some mail to the effect.

			TNX n 73's

			Jeff Goodspeed    KA9S





-- 
==============================================================================
Jeff Goodspeed, Western Electric Network Software Center, ihnp4!ihps3!ka9s
(312)-260-4838

jj@rabbit.UUCP (10/12/83)

I suggest that you look through the Supertex and Ferranti
Power FET lines.  You might also consider combinations of
a Depletion(naturally0 JFET and an Enhancement V-FET
for tube replacements.    I don't know of any useful
depletion mode Power FET's, partly because the mechanism that
most of the Power FETS use is easier done in enhancement
mode.  With a few circuit componenets, though, making 
single device replacements for many low frequency tubes
isn't impossible.

I recently hacked up a couple of power fet's into an
old tube (audio) amplifier for the heck of it.  There
weren't any real complications other than the fact that
I had to make the bias supply positive rather than negative.

If anyone out there has more info on these tube replacements,
let's hear it! I'm interested for other than tube replacement
reasons. <sigh>
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