Thanks for an excellent post, Dave. I've had my RF Parts branded 3-500ZGs
almost a year now
running AM @ 300 to 400W carrier on 40 & 75m and haven't had a single hiccup.
I also run SSB &
CW, on many other bands with a 75/40/20m dipole antenna and letting the amp
load it (Where I run
AM, the ant is a good match). I get a good dip in the plate and grid current
is okay (less than
250mA @ full output). I'm certainly interested in how these tubes age --
however, the RF Parts
3-500ZG has a full 1 year warranty and a prorated second year -- you should
have been able to get
two new ones from them for the price of one (at 18 months into the warranty).
Joe,
N3JI
> My experiences with the Chinese 3-500Zs has been questionable - a set of RF
> Parts house band tubes shorted out in my Henry 2K-3 (3300V no-load) after
> only 18 months, and this is in an amp which is only used on 80M. The
> previous Eimacs lasted 20 years...
>
> Like they say, your mileage may vary.
>
> 73,
>
> Dave/K8CC
>
>
>
> At 08:52 AM 10/24/03 -0600, John T. M. Lyles wrote:
> >I vote for the 3CX1500A7/8877-based amplifier also. I helped design an FM
> >broadcast amplifier using it in 1983, and it easily produced 1500 watts of
> >CW output class C at 108 MHz. Last year I converted a RF Power Products
> >plasma generator from 13.56 to ~4-5 MHz for a scientific application. It
> >had a questionable old tube in it, as it was pulled from another
> >experiement in a different lab. When I finished, it fired up immediately
> >at 1200 watts without a burp, no 'gas', no 'oscillations', very stable.
> >
> >That tube has a myrad of applications, and even though expensive, it is a
> >good part. There have been periods (as with many tubes) where the mfr had
> >a production glitch. However, based on the limited application of the
> >3CX1200 in ham amps, and the domination of commercial and
> >scientific/medical/military apps for the 8877, the answer is fairly obvious.
> >John
> >K5PRO
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
__________________________________
Do you Yahoo!?
Exclusive Video Premiere - Britney Spears
http://launch.yahoo.com/promos/britneyspears/
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|