[UK-CONTEST] OT 4xc350 BIAS

[alannottage at aol.com]

100 mA is the way to go.  This will mean higher diss. though.  The blower was one of the other deficiences in the design, so prepare for a warm 'exhaust', which is applying the word in the loosest sense in my experience :>)  I only ever saw 200w on an independent meter, so Richards comments re the HT would likely be pretty near the mark.  A pancake fan on the top is one of the 'conversions' I've seen, which would probably result in longer tube life, esp. under heavy duty cycle conditions.

Al G0XBV






-----Original Message-----
From: Richard Staples <g4hgi at yahoo.com>
To: uk-contest <uk-contest at contesting.com>
Sent: Tue, 14 Jun 2011 18:34
Subject: Re: [UK-CONTEST] OT 4xc350 BIAS


Hi all
The NAG suffered from many design problems
The HT was way too low ...in fact if I remember right there were 2 versions a 
low" volts and " high " volts ..200 v in between them both lumbering around 
500 - 1700 v .
The screen had no regulation at all as I recall with a passive grid input 
.designed for a 10 w drive ..all this coupled together made for a pretty poor 
ignal as the "instinct" of most NAG users was to drive the nuts off it to try 
nd achieve the quoted output power.....hence poor signal
The 350f ( original I think that was in it )  sings like a bird with a decent HT 
on it ...2 kv+ ...so I built a proper PSU for it to sit on and it worked great.
Standing current ?  most designs using 350's seem to go for 100 ma in AB1 with a 
high cut off volts at -120 I think.
Cheers Richard G4HGI


________________________________
rom: Neil Ackerley <neil.ackerley at bcs.org.uk>
o: ALEX LISTER <alexcom22 at btopenworld.com>; uk-contest at contesting.com
c: GeoffFindon <g.d.findon at btinternet.com>; regwoolley at aol.com
ent: Tue, 14 June, 2011 14:42:58
ubject: Re: [UK-CONTEST] OT 4xc350 BIAS
Alex,
What range of standing current do you have with the POT adjustment.
I believe you need 100mA standing current for a 4CX350 for SSB.
Neil, G3RIR

-----Original Message----- 
rom: ALEX LISTER
ent: Tuesday, June 14, 2011 1:49 PM
o: uk-contest at contesting.com
c: GeoffFindon ; regwoolley at aol.com
ubject: [UK-CONTEST] OT 4xc350 BIAS


Please dont laugh but I have a very ancient NAG 144 Linear (NOT!) Amp.
eems to work OK at the 200 watt plus level. So I assume valve is OK.
Only odd thing is the BIAS contriol Reading in  the Jinglish handbook says 
et to 40 ma for 4CX150 or 350 (Mine has 4CX350)
ull adjustment of POT only allows me to set for 50ma
oes it matter,
Have I a fault or is the info wrong.
ight be easier if  book was in English !
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