Hi Rich,
It depends on the band and the load, but usually ~50-65W for 550mA Ip.
At that load point, Ep is ~2650V or so, and Po ~950W. Anode gets orange
after about 30 sec key-down, but tuning to that load point and then
switching to SSB with ~950W PEP seems to keep the tube and the amp very
happy. Never measured IMD, though.
Driving the AL-80B with 100W seems to overdrive it regardless of band, i.e.,
no mo' suds, just higher Ig -- so no reason to ever do dat.
-WB2WIK/6
"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill
> -----Original Message-----
> From: 2 [SMTP:2@vc.net]
> Sent: Thursday, March 20, 2003 9:45 AM
> To: Steve Katz; AMPS
> Subject: RE: [Amps] TL922A and AL80A
>
> >
> >
> >
> >> > ** When a single 3-500Z is driven by 100w, IMD is not good.
> >>
> >> You guys keep arguing about whether a single 3-500z can be run
> >> linearly at 550mA anode current in SSB service. Has anyone
> >> actually measured the difference in IMD for a single tube run
> >> at 400mA and 550mA? Has anyone actually measured the IMD
> >> from an AL-80B at various levels of anode current? I am so
> >> sick of hearing this stupid back and forth pissing contest argument
> >> that I am tempted to go out and buy an AL-80B, the additional
> >> test equipment I would need, and do the test myself :) Talk is
> >> cheap - where is the test data?
> >>
> > [Steve Katz] I surely have no data, but I do have an AL80B on hand
> >and it doesn't require anything close to 100W to drive to Ip >400mA. In
> >fact, my exciter in its TUNE position, which runs half power (50W CW) in
> >that position, drives the AL80B, properly loaded, to >400mA Ip on all
> bands
> >-- in some cases, to >500mA, after heavily loading it to keep Ig <100mA.
> >Under those condx, efficiency is ~65% and Ep is ~2700V, e.g. 880W RF out
> for
> >1350Wdc. -WB2WIK/6
> >>
> ** How many watts of drive is needed to produce 550mA of I-plate/anode?
>
>
> - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
> www.vcnet.com/measures.
> end
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