No one is picking on you. Us old guys were always looking for a way to build
cheap stuff. This was an unusual approach. If you did not want to modify the
1625's you could use 837 tubes instead (change filament voltage or wire the
filaments in pairs in series).
I took a more extreme approach. I paralleled 4x 6AG7 pentodes and mounted
them into a heat sink make from a large block of aluminum. After conditioning
them by Bringing up voltage slowly letting them arc over and then starting over
again until I got to a full 1200 volts, I could drive them with a couple of
watts SSB or CW and got a plate input of around 300 watts. Don't know what the
output was then but made plenty of contact with the amp on 20 meters. I still
have parts of the amp laying around and have thought of doing it again and
making some measurements. Heck, I was only 19 then anyway.
The power supply was made of a TV transformer with a voltage doubler
using some AC motor running capacitors from air conditioners I found in a pile
on the side of a country road. I wound my plate choke on a tall ceramic
insulator.
At one time I took tube apart to find that unlike some metal tubes
these did not have a glass envelope inside the metal shield but a glass seal at
the bottom. If it were not for the plates being in the way it could have been a
good external anode power tube.
73
Bill wa4lav
-----Original Message-----
From: "Svante Nordenstrom" <sm3dyu@ji-net.com>
To: <Amps@contesting.com>
To: <amps@contesting.com>
Date: Sun, 15 Jun 2003 12:08:59 +0700
Subject: [Amps] 4 x 807
Apparently it was not the final comment. Glad that I did show my lack of
knowledge here, so we all could learn, as this was completely new to me. Thanks
for the corrections.
73
Sam HS0ZDY
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
in a pile on the side of a country road. I wound my plate choke on a tall
ceramic insulator.
At one time I took tube apart to find that unlike some metal tubes
these did not have a glass envelope inside the metal shield but a glass seal at
the bottom. If it were not for the plates being in the way it could have been a
good external anode power tube.
73
Bill wa4lav
-----Original Message-----
From: "Svante Nordenstrom" <sm3dyu@ji-net.com>
To: <Amps@contesting.com>
To: <amps@contesting.com>
Date: Sun, 15 Jun 2003 12:08:59 +0700
Subject: [Amps] 4 x 807
Apparently it was not the final comment. Glad that I did show my lack of
knowledge here, so we all could learn, as this was completely new to me. Thanks
for the corrections.
73
Sam HS0ZDY
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
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