[AMPS] Henry 2K2

[Rich Measures]

>
>I have decided on a new amp (after asking about recommendations here
>recently) - a good friend has a Henry 2K2 desktop amp in excellent cosmetic
>and electrical condition for $600 -

€  a bargain, provided you don't mind doing a little updating.  

>- I haven't completed the purchase yet,
>so if I'm making a horrible mistake, please tell me now before I plunk down
>my cash!
>
>Only thing that really worries me about it is the 3-400 tubes - they're
>pretty hard to find these days. I understand it's relatively simple to
>convert the 2K2 to use 3-500z's - yes? no? 
>
€  3-400Zs and3-500Zs have the same PEP output in SSB or CW service 
because peak emission is equal.  However, for RTTY service at 4000v, the 
3-500Z is a better choice.  .  Amperex still makes the 3-400Z/8163.  I 
run a pair in my SB-220 with 0v bias.  One was mfg. in 1967.  It still 
has good emission.  //  In my experiences, 3-400Zs are mechanically more 
rugged than 3-500Zs.  I have seen plenty of broken coolers on 3-500Zs and 
none on  3-400Zs.   .  .  More is not always better.  

>Any thing else I need to know about that amp that will help either confirm
>or cause me to reconsider my decision?
>
€   If it has an open frame resonant-choke, I would pot it in laminating 
resin.  Instructions are on my Web site.  //  If you have a modern 
transceiver, you might want to add high speed switching to the amplifier. 
($60)  //  Step-start would be nice.  //  Henry's glitch-R in the neg. HV 
lead is a mistake.   A glitch R should be added to the pos. HV circuit.  
//  It might be prudent to add 3A glitch protection diodes across the 
(irreplaceable) meter movements. 

-  good luck, Marty


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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