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

[John Bodine]

1) Take out the Old, put in the New.
2) Let them warm up a few minutes
3) Enjoy!

On Fri, Dec 23, 2022, 3:48 PM A Lawrence Fibich <lfibich at 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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