Since there have been so many questions about this on the list, I
guess
I should try to answer some of them. It's going to have to be
speculation,
however, because I don't work at Eimac and don't really have insider
information. In fact, it's just a fluke that I found the announcement
for
the new tube on the web.
My guess is that this is an attempt by Eimac to become more
competitive
with the overall price of an amplifier. I'd have to guess that the
socket
for this tube is inexpensive and that the tube itself will become less
expensive than an 8877 due to the relatively antiquated style of the
interface. At the same time, this tube will probably not have the
performance of the 8877 in the VHF frequency range. Well, that's
OK with me. To me it seems likely that the drive power requirement
(and gain) will be slightly impaired by the cheap interface. Like 70
watts to drive to full output rather than 65. Maybe more at 28 MHz.
Well, I'm comparing the new 3CX1500D7 with the 8877 -- and it
seems that Eimac would probably rather announce this tube in the
context of a replacement for a pair of 3-500Z's. I'd look for Eimac
to price this tube like an 8877 at first, then reduce the price a
little
until it becomes very clear that one would rather use the new tube
in any new HF application when comparing with 3-500's or 8877's.
The cheap socket and potentially more rugged mounting (no glass
chimney's) might even make this tube a candidate for a mobile
amplifier where the 3-500's never were appropriate. I guess we'd
have to leave it to speculation whether the tube internal's will be
built for that kind of abuse.
Either way, this tube has the potential of displacing the 3-500Z's
from the new amplifier market due to reduced cabinet size, and
to drive the 8877's out of the new HF amplifier market due to
price. Svetlana will probably have a very nice, comparable tube
soon as a response, and in a few years there will likely be a
low priced Chinese version in every new HF amp.
----- Original Message -----
From: "Bill Turner" <wrt@dslextreme.com>
To: "Leigh S. Jones" <kr6x@kr6x.com>
Cc: "AMPS" <amps@contesting.com>
Sent: Saturday, March 13, 2004 9:38 PM
Subject: Re: [Amps] Interesting news
> On Fri, 12 Mar 2004 20:54:35 -0800, Leigh S. Jones wrote:
>
> >The air-cooled 3CX1500D7 ceramic metal triode operates at 5 volts,
30
> >amps. The company said it delivers the same performance in many
> >applications as a pair of 3-500Z glass tubes.
>
> _________________________________________________________
>
> Aside from the heater current and 6kv vs 4kv, how is it different
from a
> 3CX1500A7? Perhaps a directly-heated cathode?
>
> According to the set of curves I have, the 'A7 could also be used in
> zero bias up to about 3kv anode voltage.
>
> --
> Bill, W6WRT
> QSLs via LoTW
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