[Top] [All Lists]

[AMPS] FS: 1 Linear Amplifiers

To: <>
Subject: [AMPS] FS: 1 Linear Amplifiers
From: (Radio WC6W)
Date: Wed, 21 Oct 1998 19:43:43 EDT
   A friend of mine recently became a silent key and in his estate are
one and a half amplifiers that may be of some interest to someone on this

***************************  The ½ Linear 

   There is a large linear that was under construction. just sort
of started.  Socket mounted, air system complete, nothing much wired.  

   The valuable parts are: 
         A  4CX5000A (the best of 4 which he owned at one point)
         A  4CX10000D (which looks well used)
         An Eimac SK-300 socket, fairly good used condition (only a
couple of the contact fingers are broken), 
        SK-306 & SK-1306 chimneys (one for each tube)
        A Johnson 200-205 ribbon coil -- 15 uh looks fairly new
        There are two new Groth turn count dials on the front panel but,
the knobs for these dials which I think I saw laying around a couple
months ago, are no longer in sight and may or may not turn up.

   There is an assortment of transformers mounted in the bottom of the

        A new looking filament transformer marked 7.5 V 100 Amps.
        A older 8" or so cube with some diode strings on top that I
suspect are for the screen.   There is also a string of six 200V 50W
zeners with heatsinks mounted to the side of the cabinet, obviously for
the screen.
        A choke for the screen supply.                   
        And two or three more small transformers that may be for control
or grid bias.
   The air system has a plexiglass plenum and an apparently new dual
squirrel cage fan.  The fan is just hooked up with test leads.... There
is a commercial manometer with its tube attached to the plenum but the
manometer itself is not mounted to anything.

   The cabinet is a gray 24" panel size rack type.  There is a panel for
the front of the amp and a latch released door for the back.  There are
no panels in the front below the shelf where the tube socket is mounted..
 The cabinet is 44"H x 27"W x 24"D overall.  It has a few scratches and
blemishes as it has been rolling (on casters) around in the garage for
years.  It probably weighs about 150 lbs. with the above described parts.

   There is no part of a plate supply evident...

*****************************  The operating Linear 

  Dick, the silent key, acquired a commercial (AM?) transmitter a long
time ago and built and rebuilt his own "daily use" amplifier in this
case.   It is currently configured with a pair of 450TL's (plus at least
6 spares),  in grounded grid.  He used to drive it with a Heathkit SB-220
& I believe it runs about 4 KW SSB.  He ran this thing for YEARS!  so at
least it is reliable.  :-)   

  The nicest part is that it has:

        Good coils switched by a very nice homebrew bandswitch.
         Vacuum variables (300pf@10KV?  and 1000pf@3KV? -- I am unsure of
the voltage ratings, they may be higher),
         Real input tuning
         a (original, I presume) commercial meter bridge with 7 meters
across the top.

  The Power Suppy components.  

        A 240 volt variac (1 foot in diameter) rated perhaps 50? amps

        The transformer is some kind of fairly modern (mid '70's
vintage?) monster.  Rumor has it that it was originally made for a shaker
table amplifier.  The U-I laminations (which are most of the thing) on
the plate transformer measure overall 18 x 11 x 6.   I would estimate
that it weighs at least 300 pounds.  It is likely at least 10KW CCS
rated.   It is open frame with some eyes at the corners for the crane to
hook up to... :-)     

       The diode bridge is comprised of a zillion low voltage diodes in a
fairly cute plexiglass housing.

       There is an 8H, 1A choke made by Collins 

        a whole bunch of 1uf 5KV caps (12?) wired in parallel 
        plus six 54 uf, 2500V continuous DC rated (they are actually
laser caps) wired in series parallel (36 uf / 7.5 KV effective).   Note:
One modern capacitor would be physically smaller than one of the laser
caps and be rated higher than all these put together!   

        There are some odds & ends like a giant power contactor, main
circuit breaker, a 7 meter bridge assembly, and of course the rest of the
stuff to make the 450TL's go.

 The bad part is that the cabinet is navy gray, about 7' hi, about 3'
wide, and 2½' deep and the whole thing likely weighs 700lbs....


 I would like to sell both of these units together for $1500.  The
variac, power transformer, vacuum variables and some of the other
components from the 450TL piece would go along way toward completing the
other amp.  You could just toss the big cabinet on the way out of town...
but, please don't let the widow who helped repaint the thing 30 years ago
see you do it!   

  I am afraid that this stuff does not easily lend itself to shipping
which would certainly have to be by truck freight.   A lot of the parts
would have to be removed and packed separately.  The big transformer for
instance is not bolted down and would have to be palletized.  If you are
far away, perhaps you have some friends in Los Angeles you could impose
upon.   :-)

  Thanks for reading all of this & have a nice day!

  Marv  WC6W  310 649 3111 (Reasonable hours Pacific Time please)

You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at
or call Juno at (800) 654-JUNO [654-5866]

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>
  • [AMPS] FS: 1 Linear Amplifiers, Radio WC6W <=