[Amps] Big HV Supply

Jim Thomson jim.thom at telus.net
Wed Aug 8 11:52:44 EDT 2018

-----Original Message----- 
From: Carl
Sent: Wednesday, August 8, 2018 7:44 AM
To: Jim Thomson ; amps at contesting.com
Subject: Re: [Amps] Big HV Supply

<The LK-550 runs three 3-500's and cooling would likely limit power as it is
a fan. Ive had them up to 2200W or so with 150W drive....nothing to brag
about tho!

Ive built several LK-800's for 6M EME that do a solid 5 out without
complaining and going to a good EBM fan.

On HF I dont know how well the bandswitch will hold up over time and the
fixec C used needs beefing up.

Another thing I dont know is tube life at that power but money isnt
important to some.

BTW what is a full output YC-156 going for these days? It came from Tom,
WD8??? ages ago. Also have a filament xfmr and one of those UK sockets all
set up for good air flow. I'll never get around to building another amp and
dont need QRO here.


##  YC-156  does not use a socket.  Its got a grid flange that just bolts to 
Then the fil lugs below.  Indirectly heated like a 8877.   Eimac sez 6 min 
warm up minimum, but
Reid Brandon and I talked about that years ago, and he highly recommended  a 
full 8 mins.
Typ they go for  $400.00  for a good one.  I dont  recommend it these days 
as they
are real scarce... and are just pulls of pulls.  The 11m ops have beaten the 
crap out of them
too.  I designed a YC-156  80-10m for a local buddy, and he bought  a total 
of  12 tubes, TWELVE,
and only 3 are any good.   What typ happens is you end up with  a grid to 
fil short, or grid to cathode
short after just 5 mins..with fil on, blower on, and NO B+.   Without at 
least  2-3 known  good tubes,
I would not build a YC-156 from scratch.   Loads of  YC-156 amps out there, 
so should be easy to sell,
with the provisio that the tube functions in a working amp.   Buddy bought 
every  YC-156 he could
get his hands on...and 9 were duds.   One good one, and  2 x semi good ones.

##  That   OM power  OM-4000 HF  sells for  $6K..and does an easy 4-5 kw out 
all day long.  It comes
with a FCC approved input board, which has the input attenuators built onto 
it,  so it needs like 60+
watts to drive it to 1.5 kw.   The attenuator is easily bypassed, then it 
can easily be driven to  4 kw
out with just 20 watts..and more with a bit more drive.   Also comes in 
both a manual..and full auto
version..and both use a pair of chinese   FU-728F tubes. 
They also make a remote small console to remote the amp, if u want, cheap, 
like  $288.00
Emtron, when they were in business, also made a similar amp, same pair of 
chinese tubes, and they rated
their version at 4.5 kw out.

##  JA6TAY,   from bear-el   now has a separate company that mass produces 
his  160-10m,  3CX-3000A7
commercial amp.   5++ kw out with just 200 watts of drive.   Looks sorta 
like a Henry radio  8K ultra.. but
actually built correctly.  RF deck  +  B+  supply etc, sit in a 100 kg 
box..complete  with 7.5 kva CCS xfmr.
Small box in shack contains the  myriad of pre-sets, and fine adjustment 
tune control etc, +  5 x panel meters.
2nd item down.
I have all the schematics for it.  Uses a motor driven vac tune cap..and a 
motor driven   10 kw rated
roller coil, then a myriad of vac relays  to switch in various combo's of 
fixed  load caps.   He ships a helluva lot of em.

## which UK socket do you have ?   There is some outfit in the UK I believe 
that makes quality  SK-1320 sockets
for the bigger GG triodes...... at a relatively cheap price... like  188 
Euro's... like  $230 US funds.   On a related note,
if  the grid driven version of the socket is used... which is called a 
SK-1300..and u try to modify it for GG, it can be done,
BUT, in addition to 4 x cu straps being installed, on edge, so not to impede 
airflow, the 4 x small ceramic insulators
on the socket assy also have to be removed..and replaced  with aluminum 
threaded cylinders.   If the al cylinders
are not installed, all hell breaks loose, and a parasitic will result.  With 
the 4 x al cylinders and  4 x straps, its  rock
solid..and no suppressor required on the series of GG triode tubes that use 
the SK-1320 socket.
http://www.aluminumspacers.com/    cheap source for solid  AL spacers with a 
hole down the center,,, or a threaded hole.
U can get virtually any OD  + ID  and any thread size..and also overall 
length.   Saves a lot of screwing about fabricating
them by hand.

Sri for the diatribe, but thats  this weeks bits of latest info that I know 
of.   Only other  recent news is the availability
of  the teflon version of  LMR-600.   A buddy found a source, they typ come 
in 17 ft lengths with  type N  connectors.
The  Type Ns  are tossed, and replaced with  7-16  din or  .875  EIA  flange 
connectors.  Typ used for  rotor loops

Jim   VE7RF

----- Original Message ----- 
From: "Jim Thomson" <jim.thom at telus.net>
To: <amps at contesting.com>
Sent: Monday, August 06, 2018 12:29 PM
Subject: [Amps] Big HV Supply

> Date: Sun, 5 Aug 2018 15:46:55 -0400
> From: "Carl" <km1h at jeremy.qozzy.com>
> To: "John Keating" <john.keating at outlook.com>, "Jim"
> <jimw7ry at gmail.com>, "'Herbert Schoenbohm'"
> <herbert.schoenbohm at gmail.com>, "'Amps group'" <amps at contesting.com>
> Subject: Re: [Amps] Big HV Supply
> <All the big Amp Supply transformers were Dahl, some had a tapped HV 
> winding
> <for the LK-550 and LK-800 and others were custom non advertised for the
> <3CPX800A7 LK-800
> <You would be surprised at how many went to 160M "big guns". There is 
> little
> <honor on that band any longer.
> <Carl
> ##  How much power can u get out of a LK-550  or  LK-800..with a big xfmr 
> ?
> I dont even know what tube  or how many many tubes were in those amps.
> What are we talking abt here, like  3 x 3cpx800a7s   putting out 3.5 kw or 
> what ?
> I wouldnt get wound up abt a lousy  3 – 4db esp on 160m band.  IMO, they 
> should
> increase the limit on 160m.  Thats  one band where some extra.. oomph 
> would work,
> esp with sky high noise levels.   Noise level with typ ssb rx filter band 
> widths typ  results
> in high noise levels... making life a bitch on 160m  ssb.
> Jim   VE7RF
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