| You might run into plate choke heating if resonances atre close as well as 
switch arcing which seems to be common with that amp. 
I thru the calculator away several times and installed a LK-500 thru 800 
complete tank in a couple of L4B's and got good 160-10M coverage including 
WARC.  The tanks were left over from 6M conversions. 
If Amp Supply could get away with one tank for all the amps I said what the 
hell...!! Saved a lot of time and woked fine. Even used their plate chokes. 
Carl
KM1H
----- Original Message ----- 
From: "Paul Baldock" <paul@paulbaldock.com>
To: "Carl" <km1h@jeremy.mv.com>; <amps@contesting.com>; 
<mikflathead@aol.com> 
Sent: Sunday, February 16, 2014 5:16 PM
Subject: Re: [Amps] L4B supply
 I run my L4-B at 800V (no load) above the original design. 3100V key down 
at .7A.1600W PEP out. It's been handling it fine for about 6 months now. I 
think the cooling is probably inadequate but I like to live on the edge. 
The load impedance is not messed with significantly because with the 
increase in voltage there is a proportional increase in current. I did  add 
a timer so the fans stays on for 10 mins after power down and a few other 
mods.
- Paul
At 01:17 PM 2/16/2014, you wrote:
 Use a transformer from an Ameritron AL-572, it will give you very close to 
the original and not mess up the tubes load impedance. It is in the MFJ 
catalog and reasonably priced compared the new alternatives. The last 
thing to do is go overboard with voltage as the circuit wont handle it 
well.
Carl
KM1H
----- Original Message ----- From: <mikflathead@aol.com>
To: <amps@contesting.com>
Sent: Sunday, February 16, 2014 3:27 PM
Subject: [Amps] L4B supply
 I recently acquired a nice L4b amplifier. It has no tubes or supply. It 
is in very nice condition. If you were to build the "ultimate" supply for 
this what would you use for a transformer. I would think a full wave 
bridge would be the way to go. Any comments? Thanks Mike
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