##   I  can  toggle  bias on the back of the L4Bs so a pair  of  4-400s can 
be  used...with NO  bias.
But  I  forget the  idle current,  with  4-400s..and no  bias  on a L4B.
 ##  with  3-500Zs,   Idle  is  40ma  on  CW...and  100  ma  on  ssb.... 
using  10 x  1N5408s  In  series.  Same  L4B.
IMD  is  good on  1900 vdc  cw position....  625 watts  pep  out.   Ditto 
with   1290 watts  pep  out on  ssb  position.
Jim    VE7RF
 -----Original Message----- 
From: dj7ww@t-online.de
Sent: Saturday, November 2, 2019 8:29 AM
To: 'Jim Thomson' ; amps@contesting.com
Subject: RE: [Amps] SB-220 HV Transformer Wanted ; thread stolen for
Jim,
OK, I read it in the context with tube GG amps.
I don´t use zero bias triodes in my glass tube amps but highµ connected
tetrodes. The pair of RS1002A in my L4B draw only 30mA, no key clicks and
IMD3 >30dB in SSB.
Those tubes are made for and run class B as well with grounded cathodes and
proper screen and bias voltages.
73
Peter
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jim Thomson
Sent: Samstag, 2. November 2019 14:37
To: amps@contesting.com
Subject: [Amps] SB-220 HV Transformer Wanted ; thread stolen for
Date: Fri, 1 Nov 2019 19:54:21 +0100
From: <dj7ww@t-online.de>
To: "'Jim Thomson'" <jim.thom@telus.net>, <amps@contesting.com>
Subject: Re: [Amps] SB-220 HV Transformer Wanted ; thread stolen for
<No Jim,
<A PP RF amplifier does not need LP filters if using pi-net output
circuitry.
##  Im  talking  about a PP  SS  RF  amp.....  like  ur  typ 1.5 kw  SS
amp....or  xcvr.
<And a GG amplifier running class B does not generate key clicks, my main
amp
<is running ZERO bias class B for more then 40 years in CW and SSB.
##  any  high Mu  GG triode  operating  with  ZERO  BIAS  will  draw LOADS
of
idle  current....  and  is  operating  class  AB2.
##  Increase  bias  voltage,  till idle  current  drops  to  0-5  ma....
and  u  will  get  key  clix,
try it yourself.
Jim    VE7RF
<73
<Peter
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