----- Original Message -----
From: Rich Measures <measures@vc.net>
To: Doug Person <w4dxv@ibm.net>; amps <amps@contesting.com>
Sent: Friday, June 11, 1999 9:41 AM
Subject: Re: [AMPS] Finally - a real amp
Rich,
That seems quite a bit less than what the manual suggests. However, the
reduced power would hardly be noticable to anyone. I wonder what the
affects of SSB would be rather than full carrier. If I tune up the amp
using no more than the 400ma plate current and 65 watts drive, would pushing
the power to 100 watts PEP input during normal SSB operations result in
additional stress on the 3-500z, or perhaps increase distortion? It seems
to me that SSB is vastly less stressful on components over continuous
carrier because it is largely made up of fast transients.
Now that I've gotton your input, I'm sorry to report that while tuning the
AL-80A on 17 meters with 500ma ip and 150 ma of ig, A somewhat loud and most
unpleasant noise ocurred within the amp after which there was no current
indicated for either ig or ip. Did I fry the tube?
Does anyone know of any issues about this amp such as modifications that
should be made?
tnx - Doug -- W4DXV
>I have at long last obtained my first serious amplifier. It is an
>Ameritron AL-80A which I find vastly more desirable than the current
>AL-80B. The later being housed in the thin (cheap) and easily warped
>aluminum not unlike the usual stuff of which most MFJ products are
>encased. The AL-80A is a product of the original company owned by Prime
>Instruments. It is of all steel construction, loads up smoothly, works
>well on the WARC bands and seems to still have the original Eimac tube.
>
>I will accept everyone's congratulations in advance to save time and get
>to my questions which are essentially, in a nutshell, what are the best
>operating parameters to observe when running the classic single 3-500Z
>amp? The manual indicates the following:
>
>1. Max drive of 100 Watts
>2. Max plate current of 550 ma
>3. Max grid current of 200 ma
>4. Max power out of 1000 watts
>
>It seems to me I recall some discussion about these values, but don't
>recall the conclusion. I would appreciate any advice regarding proper
>operation of 3-500Z amplifiers.
>
? Eimac rates the 3-500Z at 400mA max. for linear service and 65w drive.
My advice is to believe it. The 550mA figure may have come from one of
our recognized "experts". 200mA of Ig is within the Eimac rated grid
dissipation rating of 20w. . A linear 1000w out figure is possible with
a 4000v anode supply.
- later, Doug
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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