[HomeBrew] Amplifier

[James M. Walker]

Hi Larry,
Yep, I do as I am sure others have also. My High Power homebrew HF rig is a
single 4-1000A in class "B" grounded grid, with 3500 VDC on the plate, tuned
input for 160 - 10 meters, and driven by a DX-100 with 125 watts output on
AM
and CW. I used all heavy duty parts in it, vacuum variables in the PI
network and
Heavy duty (broadcast quality) coils and RF switches. They work fine and
coast
along, when I started this setup design, I gathered up (3) three 4-1000A
tubes so
I would have spares in case of trouble, I have yet to use either of the two
spares as
the thing just runs, no troubles.

If you want to go the standard route, grid driven, I think you could get
along with
around 25 watts drive. Of course modes are important, my rig was designed
for
AM linear and CW only, as opposed to Class C plate modulated. Guess it
depends
on what you want to run it for mode wise.

One other recommendation, build the power supply to handle 500 MA at around
5 KV
and make it adjustable, that way power control is a breeze.

Your mileage may vary.

Jim
WB2FCN
http://eshop1.chem.buffalo.edu


----- Original Message -----
From: "Larry Thomas" <aa3px at nationi.net>
To: <homebrew at mailman.qth.net>
Sent: Wednesday, October 06, 2004 7:48 AM
Subject: [HomeBrew] Amplifier


> ** Please do NOT cross-post messages in the TO: or CC: field of the e-mail
message. **
>
>
> Anyone here have any experience with 4-1000 amp's. I have several tubes
and
> thought it would be nice to build up a big amp from 1. I believe 2 would
be
> too hard to drive and besides that who needs a megawatt ? Just a project
> for the winter I would like to do.  Schematics would be interesting as
> well. I have seen several different ways of doing it be haven't heard
> what's best.
> Thanks
> Larry
> AA3PX
>
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