Amps
[Top] [All Lists]

Re: [Amps] Requesting opinions on a Drake L-4b's tubes

To: "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] Requesting opinions on a Drake L-4b's tubes
From: A Lawrence Fibich <lfibich@sbcglobal.net>
Reply-to: A Lawrence Fibich <lfibich@sbcglobal.net>
Date: Fri, 23 Dec 2022 23:31:31 +0000 (UTC)
List-post: <mailto:amps@contesting.com>
 Please accept apologies - I misspoke on being push pull - surely finals are in 
parallel - I was more focused on trying to explain simply and 'fingers did 
their thing' again, sorry for misspeaking. LarryW6EF
    On Friday, December 23, 2022 at 12:48:28 PM PST, A Lawrence Fibich 
<lfibich@sbcglobal.net> wrote:  
 
 I just acquired this Drake L-4b as the third owner and no nothing about its 
history. It puts out 400 watts with recommended Plate and grid currents (.56 
amps, and 225Ma respectively). If overdriven (.8 amps; 100ma) it will do 600 
watts. At 'idle/resting' should be 0's but shows .1 plate amps & 75 ma grid 
current- which I think shows a tube problem.
Now my request for an opinion, what do you suggest:  
1. I got 2 unopened tube boxes from Drake - thinking to simply replace/use them 
and see what happens.
2. Surprise - 1 is the 3-500G- (Graphite plate) - the other turns out to be a 
3-500Z (old style) . 3. The unit has 2 (original/old) - 3-500Z's in it and 
really no way to test them4.  So? what to do?5. Live with it, and leave the 2 
in the unit and live with 400 watts and? or- maybe overdrive them and go for 
600 watts? ? how long do you think they would last?6. Use the 'new' 3-500Z with 
one of the 'old' 3-500Z's?7. Use the 'new' 3-500G (graphite) with the 'new' 
3-500Z?8. Use the 'new' 3-500Z with one of the 'original/old' 3-500Z? 
Of course, the finals in the Amp are push pull configuration -2k PEP & 1K CW 
input watts. 
Thanks for ALL your suggestions/recommendations.  73Larry F.W6EF
  
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
<Prev in Thread] Current Thread [Next in Thread>