[Amps] 6m 2X 3-500Z amps

[Steve Katz]

I never saw it published (that I can recall, but the memory's the second
thing to go!), but both Swan and Raytrack made and sold quite a lot of 2 x
3-500Z 50 MHz GG amps, and they worked, and they were stable.   But they
weren't particularly easy to drive.  The Swan Mk VIB used 2 x 3-500Zs on
six, tuned input, and required about 150W PEP to get full smoke from
it...which was just about right, since the Drake TR-6 a lot of people used
to drive it did deliver 150W PEP.  The Swan-250C a lot of people used to
drive it delivered about 100W PEP and could drive the amp about 2/3 of the
way...still delivering close to 1 kW PEP out.

Based on the Swan design, I built my own dual 3-500Z 6m amp and it worked
exactly as theirs did (and was as hard to drive).  With a bit more plate
voltage (like maybe 3300-3500V) it probably would have produced a bit more
smoke with a bit less drive...as I recall both the Swan power supply and my
homebrew one only delivered about 2700Vdc.

It was a very stable design.  I had a plate choke that resonated about 70
MHz or so and that didn't seem to be a bad thing.

WB2WIK/6

"If everything seems under control, you're just not going fast enough." -
Mario Andretti

> -----Original Message-----
> From:	John Farber [SMTP:kg6i@worldnet.att.net]
> Sent:	Thursday, December 05, 2002 1:17 PM
> To:	Amps@contesting.com
> Subject:	[Amps] 6m 2X 3-500Z amps
> 
> I'm looking for schematics/advise on building one of these. I can only
> find
> circuits using a single 3-500Z tube. Anyone ever actually built one of
> these
> that worked and was stable? I wish it to be a GG ckt, with 60-100 W drive
> for legal limit, or close to it, out. Thanks, 73 John
> 
> 
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