Pete KE9OA Wrote:

Does anybody have a copy of the April 1977 QST?
The article I am interested in the the one by
Howard Sartori, entitled
"solid tubes, a new life for old designs".


Pete, the last time I did this, I had dual gate MosFET devices. These
days they are harder to find, so I'd probably use two JFETs in cascade to
get more or less the same effect.

I vaguelly remember the article recommends dual gate MosFETs but I will
admit, it's been a long time since I read it.


Jim Pennell
N6BIU


--

21:55 Pacific Time Zone
Jan 14 2008

International Time
05:55 UTC
15.01.2008

I will give it a whirl. I do have some of the dual gate devices on hand. I
have to do a board layout for each of the modules, that will have a pin
field that has the same pattern as the tube base. Out of all the receivers I
have / have had, I think the
R-388 is still my favorite.

Pete

"Jim" wrote in message
...
Pete KE9OA Wrote:

Does anybody have a copy of the April 1977 QST?
The article I am interested in the the one by
Howard Sartori, entitled
"solid tubes, a new life for old designs".


Pete, the last time I did this, I had dual gate MosFET devices. These
days they are harder to find, so I'd probably use two JFETs in cascade to
get more or less the same effect.

I vaguelly remember the article recommends dual gate MosFETs but I will
admit, it's been a long time since I read it.


Jim Pennell
N6BIU


--

21:55 Pacific Time Zone
Jan 14 2008

International Time
05:55 UTC
15.01.2008

Dual Gate MosFets are convenient for a tube replacement....

As I recall, I rectified the old filament voltage, regulated it, and made
that the new "plate" voltage. Other than that, JFETs and, when necessary,
Dual Gate MosFETs did most of the work.

Well, had to mess with the "grid" bias resistors too.

OK, so I used an audio Amp IC for the last part of the audio chain.
Still, all in all, the conversions I did were surprisingly easy.


Jim


--

22:34 Pacific Time Zone
Jan 15 2008

International Time
06:34 UTC
16.01.2008