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
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