[TenTec] Hercules 444 amp

[Duane Calvin]

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.)

	73, Duane 

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




-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Wade Staggs
Sent: Sunday, August 10, 2014 12:54 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Hercules 444 amp

*At least for now, even if we could afford one of the Big Gun Solid State
Amps. I would hope that we would have the good sense to stick with an Amp
which runs 1 or 2 of the 3-500ZG Triodes. They are as tough as Nails. How
can you argue with a system that with proper care, will run a lifetime. The
tubes in our SB-220 are Original. This means that they are approaching
their Fortieth Birthday. We recently replaced the Capacitors and Relay. The
Amp was still working Great when we did this Preventative Maintenance.  And
Even a Cave Man with Knives and Bear Skins can repair the Amp if needed. *
*                                                                     73
from Wade/KJ4WS*


On Sun, Aug 10, 2014 at 12:01 PM, Robert <rmcgraw at blomand.net> wrote:

> Many to most design parameters do change radically when converting from
> BIPOLAR to MOSFET devices.
>
> I seen to think MFJ does have their products in the reach of the average
> ham.  I find typically they offer reasonable designs, reasonable quality
at
> reasonable prices. Maybe it's the hams average reach that needs adjusting.
> The days of the SB-200 and SB-220 KIT prices are long gone.
>
> Good quality amps, those that are clean and don't spew garbage across the
> bands, require good design and good quality parts.  Then add a high duty
> cycle and it places more demand on the designs and the parts choices.
>
> 73
> Bob K4TAX
>
> Sent from my iPhone
>
> > On Aug 9, 2014, at 5:38 PM, Brian Carling <bcarling at cfl.rr.com> wrote:
> >
> > So maybe the Hercules can be converted to use MOSFETs. Seems like it
> should be possible.
> >
> > I also think MFJ needs some competition on MOSFET linear amplifiers to
> get the price point within reach of the average ham.
> >
> > There is just not a good reason why so many linear amplifiers should
> cost $3500 to $9500 when you look at the parts cost and manufacturing
cost.
> >
> > [/SOAPBOX]
> >
> > Best regards - Bry Carling
> >
> >
> >
> >> On Aug 9, 2014, at 5:24 PM, Douglas <sparks06524 at yahoo.com> wrote:
> >>
> >>
> >> Date: Sat, 9 Aug 2014 10:12:45 -0400
> >> From: Brian Carling <bcarling at cfl.rr.com>
> >> To: "k9yc at arrl.net" <k9yc at arrl.net>,
> >> Discussion of Ten-Tec Equipment
> >>    <tentec at contesting.com>
> >> Subject: Re: [TenTec] Hercules 444 amp
> >> Message-ID: <86F80EE5-1044-42AA-9641-D8859123467B at cfl.rr.com>
> >> Content-Type: text/plain;
> >> charset=us-ascii
> >>
> >> Seems like a lot of RF power transistors are similar, so it
> >> should not be too difficult to find a substitute.
> >>
> >> Best regards - Bry Carling
> >>
> >> ------------------------------------------------------------
> >>
> >> Ah -  but it is hard to find a substitute. The Ten-Tec factory can't
> find one.
> >>
> >> There were only a few designs of 250 to 300 watt 50V bi-polar power
> transistors made. The remaining ones are hard to get and have an HFE that
> is too high. Several such transistors have been totally discontinued.
> Motorola for example is out of that business. M/AComm bought some of their
> designs but in general bi-polar RF transistors are considered passe. RF
> MOSFETS are now the name of the game.
> >>
> >> Per another poster: I've not had trouble with the power supply drifting
> upward with temperature rise. Perhaps they solved that with compensation.
> >>
> >> 73,
> >>
> >> Doug/WA1TUT
> > _______________________________________________
> > TenTec mailing list
> > TenTec at contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
_______________________________________________
TenTec mailing list
TenTec at contesting.com
http://lists.contesting.com/mailman/listinfo/tentec