[Amps] RE: What to do with tubeless sweep tube FL2000

[Will Matney]

Yea,
They can be converted to the 6KG6-EL519 or EL509 sweep tube. From tests 
here using the Yugoslavian version (EI brand), I found that they were 
just as good as the 6JS6, 6LF6, 6KD6, and 8950 with comparable power. 
These tubes are slightly taller and have a taller anode thus helping 
with the power rating. The difference is that the 6KG6 uses a 9 pin 
magnoval socket and the 6KD6 uses a 12 pin compactron. There is one 
problem though, the 6KG6 was designed with a 700 Vdc anode voltage and 
the 6KD6 a 900 Vdc voltage. The plate voltage will need to be turned 
back to at least 800Vdc under load. That 1200 Vdc under load should be 
about 1043 Vdc. Thus, the plate resistance will change and accordingly 
the tank circuit also. The input resistance and capacitance is different 
so the input tuning will be different also. I have tried these both grid 
driven and grounded grid and work ok. On grid driven, I ran them with an 
800 Vdc plate, 400 Vdc screen, and -120 Vdc control grid. G-G service 
was 800 Vdc plate with -12Vdc on the control grid and using a grid leak 
resistor-capacitor network. The Svetlana version of the 6KG6 is actually 
a 6P45 tube and is a shade different in it's specifications than the 
real 6KG6-EL519. The internal connections are the same but the other 
specs like capacitance, etc. are different.

Will

Message: 5
Date: Fri, 25 Jun 2004 17:27:14 -0400
From: "donii at sympatico.ca" <donii at sympatico.ca>
Subject: [Amps] What to do with tubeless sweep tube FL2000 ?
To: Amps at contesting.com
Message-ID: <40DC98B2.1060607 at sympatico.ca>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I've just gotten this nearly mint and hardly used FL2000 for a song. The 
original 6KD6's are nearly new but I would like to keep them for my 
great FT-501 with CW filter and very tired finals. Is there some type of 
conversion the FL2000  can undergo with another type of tube(s)? It 
would be a pity just to gut it because I stole it's tubes!  Am I barking 
up the wrong tree? Maybe I should retube the FT-501 and use the FL2000??
The FL2000's  power supply gives 1200 volts dc. and I can do moderate 
circuit modifications to accomadate one or more tubes. Maybe put a 
doubler circuit in the H.V. bringing it up to 2400 v. then I could put 
in 572's or something else?
Another question: Are the four original 6KD6's in the FL2000 matched ?
73's all
VE2FAR