>Hi folks,
> I just found a very nice Amp Supply LK500ZB for sale. It has a pair of
>new graphite 3-500Z tubes and an outboard case-mounted Peter Dahl
>transformer. The original internal transformer is still good and still
>inside, but disconnected. The external transformer is significantly larger.
>FWB design, pretty good regulation, and it will make 1400 watts with 100w of
>drive. It uses a split-chassis cooling system a-la-SB220 which seems quite
>effective.
>
>I want to replace my SB-220 with this amp for two reasons. First, it has
>160m, and I'm tired of hearing stuff I can't work on that band. Second, I
>chase DX on RTTY and operate in the occasional contest, and this amp seems
>better suited for occasional RTTY use.
** Agreed. The SB-220's 500VA or so HV is somewhat less than wonderful
for RTTY.
>So here's my question for those of
>you who are familiar with the design of this amp. Given the tubes, cooling
>system, tank circuit, and the fact that it has an outboard heavy-duty
>transformer, how much power could I reasonably run on RTTY with it?
** Maybe 1000w provided you replace the LK's 160m padder caps with some
real tuned circuit type caps that can handle the c. 10A of RF circulating
current. However, for serious 160m contesting, 1000w is about 6db short
of what's needed.
>The
>owner says he thinks 800 watts or so would be OK in contest situations, and
>more if I'm just playing in a pileup. What do you think?
>73,
>Doug, K4DSP
>
>P.S. I'm open to other recommendations too, but I prefer glass tubes (cheap
>and readily available).
>
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>
- R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
www.vcnet.com/measures.
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