[TenTec] Hercules 444 amp

[Duane Calvin]

Sure, Carter.  My Centurion came new with two RF Parts 3-500ZG's.  This was
fairly early in the life of this tube configuration (graphite anode variety)
and manufacturer, and TT had just started advertising they were using them.
After about 2 years of occasional use, generally running between 600-900W
(and all settings well within the safe zone), one of the original tubes
developed the infamous grid/cathode short.  I replaced the original tubes
with a new matched-pair of 3-500ZG's from RF Parts, and shortly after that I
sold the amp (with a used spare tube).  I know lots of guys who have had
Heath and other amps with EIMAC 3-500Z's in them for years with very few
problems.  Yes, mine could have been a late early life failure, but at that
time I was reading of others having similar problems with these tubes.  That
was a few years ago - maybe RF Parts has improved their relationship with
the factory that makes these tubes and all is well today.  So, my "data"
consists of one in-person experience along with a number of other reported
failures around the same time, for whatever that's worth.  The implication,
to me, is that the tubes at that time were not of the same quality level as
EIMAC's.

	73, Duane


Duane Calvin, AC5AA
Austin, Texas
www.ac5aa.com  




-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Carter
Sent: Sunday, August 10, 2014 8:33 PM
To: tentec at contesting.com
Subject: Re: [TenTec] Hercules 444 amp

On 8/10/2014 2:08 PM, Duane Calvin wrote:
> This was certainly true of the  EIMAC tubes, as long as you cared well
 > for them.  I've not had as good a luck with the current
 > Chinese-sourced tubes (specifically, the 3-500ZG's from RF Parts,
 > which the Centurion uses.)

My Centurion (which I obtained used 20 years ago) finally had one of its 
tubes [rather spectacularly] go to the great beyond.

Unless I get really lucky and find a NOS pair at the e-place, it seems 
like my only other option is a matched pair from RF Parts.

Could you please elaborate a bit on your statement above that says "I've 
not had as good a luck with the current
Chinese-sourced tubes (specifically, the 3-500ZG's from RF Parts)".

73,
Carter K8VT
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