[Amps] Amp Supply Amps

[gudguyham at aol.com]

The LK5OOnt is good for nothing in my book.  You have to select a frequency in each band that you want to optimize the output and then load it for that frequency on each band.  It will work ok “ on and around “ the frequency you load if for.  QSY too far and the power drops off the further away from the loaded frequency.  This amp is good for a net  control operator who operates the same frequency all the time on different bands and other such “channelized” type operation.  The LK800 on the other hand is a powerhouse amp with 3 3cx800 tubes.  Good for 3kw easy or loaf at legal limit.  Has a big external transformer.  Nice amp.  Both amps however do not work very well on 160 because they lack sufficient inductance.  It manifests itself by seeming to always want more capacitance.  You can pad the load indefinitely with more C and it still won’t be enough.  There is no substitute for the correct amount of inductance.  A few vintage amps suffer from this.  Similar is the TT Centurian. You get what you get on 160 and that’s it.  I had a ***mint*** LK550ntc I couldn’t sell it at a bargain price. I could have “stuck” somebody with it for a decent price if I didn’t offer to interrogate the buyer to see if he knew exactly what it was.  Lost every sale when I explained that amp throughly.  The LK800 is a gem however.  

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 On Tuesday, December 15, 2020, Tom Hellem <tom.hellem at gmail.com> wrote:

Recently inherited a LK 800C and a LK 500 NT from the estate of an SK.
I know nothing about this particular brand of amp.
Any input from members of the group would be appreciated.

Are they worth keeping around? Are there known issues with either of these?
The grid current meter seems not to work on the LK800, and it seems to
require full mesh on the loading and plate tuning capacitors on the low
bands, feeling like there may not be enough capacity to really realize the
output that the amp is capable of.

The LK500 is a no-tune amp because it has a separate output network for
each band, adjusted by the factory I presume. Does anyone know if the
output networks need to be tweaked for full output after a number of years
of use?

Thanks in advance for any thoughts or suggestions.

Tom
K0SN
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