[Amps] gettering question

[hs0zed at csloxinfo.com]

A little caution when 'pulling a few turns'. The choke can be resonant around
25MHz and 'pulling a few turns' will undoubtedly raise it. The risk is that it
could become a little toasty if you use the amp at the bottom of 10m. It might
be worth making some measurements first.

How is the choke in the LK-500 different from the Alpha? About where is it
resonant? Might be useful info for reworking other amps.

Martin, HS0ZED
 


Quoting Carl <km1h at jeremy.mv.com>:

> 12M is the problem band and removing 3-4 turns may move the resonance as it 
> does with Dentrons. Since I dont use my 76PA on WARC (The LK-500ZC does well
> 
> there) I havent tried it.
> 
> Carl
> KM1H
> 
> 
> ----- Original Message ----- 
> From: "Bob K6UJ" <k6uj at pacbell.net>
> To: <amps at contesting.com>
> Sent: Wednesday, March 28, 2012 11:43 AM
> Subject: Re: [Amps] gettering question
> 
> 
> > Carl,
> >
> > Thanks Carl,  I will be going thru it and plan to replace all the filter 
> > caps, resistors, and the electrolytic.  I got this amp in a trade
> > and although it has been converted to two 3CPX800's,  he didnt do anything
> 
> > else to it.  Im pretty sure it still has the original filter caps
> > so it definetely needs these replaced.
> >
> > I have another 76CA, my daily use amp,  which I have converted over two 
> > two 3CPX800's, changed the filter caps plus the things you
> > recommended and it is running great.
> >
> > BTW,  what WARC bands are safe to use with the Alpha 76's ?    If I 
> > remember, there is one band I should avoid.
> >
> > 73,
> > Bob
> > K6UJ
> >
> >
> >
> >
> > On Mar 28, 2012, at 7:12 AM, Carl wrote:
> >
> >> Id be more concerned about the PS if the filters havent been replaced. 
> >> There are also a few resistors and a small electrolytic that change 
> >> value/go leaky.
> >>
> >> An hour should be sufficient as that tube appears to age well if it isnt 
> >> a well abused pull.
> >>
> >> Carl
> >> KM1H
> >>
> >>
> >> ----- Original Message ----- From: "Bob K6UJ" <k6uj at pacbell.net>
> >> To: <amps at contesting.com>
> >> Sent: Tuesday, March 27, 2012 11:48 PM
> >> Subject: [Amps] gettering question
> >>
> >>
> >>> With an amplifier that uses a pair of 3CPX800's,  like my converted 
> >>> Alpha 76CA,  how long should I
> >>> let it sit there heating the filaments before using,  when it hasn't 
> >>> been used for 2 or 3 years ?   Couple of hours, 1 day, ?
> >>>
> >>> Bob
> >>> K6UJ
> >>>
> >>>
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