[Amps] L4B supply

[Jim Thomson]

Date: Sun, 16 Feb 2014 14:16:28 -0800
From: Paul Baldock <paul at paulbaldock.com>
To: "Carl"
<km1h at jeremy.mv.com>,<amps at contesting.com>,<mikflathead at aol.com>
Subject: Re: [Amps] L4B supply


###  The oem L4B ran at .8A @  2500 under load.   ( 2650 on RX..and  2600 keyed, but with no drive, just idle current)

To keep the plate load  Z the same... u would have to increase the plate current to .992 A 

The bandswitch in the L4B can only be pushed so far.   Although it makes the clunk clunk clunk noise when
switching bands... its not heavy duty.   It does have a heavy duty detent however. 

The V regulation on the oem L4PS HV supply is superb..considering it uses a doubler and 8 x 200 uf caps.  

Don’t push it past 3100 V under load.   The tune cap and or bandswitch will cut loose on u next. 

The manual sez its good  from 3.2 to 30 mhz continuous...provided the tuned inputs are tweaked.   I have used the
oem plate choke on 30-17-12m..and it works fine.  Dunno whewre the plate choke resonates. It has to resonate somewhere. 

Jim   VE7RF




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