[AMPS] 3CV1500A7

[Paul Christensen]

Thanks so much for the reply Dick.  These tubes are far scarcer than I had
envisioned.  Nevertheless, I'll begin my pursuit for a spare and hopefully,
it won't take me nearly as long as it did just to find an unmodified vapor
amp!

During my search for this amplifier, a rumor had circulated that Svetlana
may begin production of the 3CV1500A7.  I assume that any intellectual
property rights to its design have long since expired?  If this tube is used
in only one single application, I fail to see how any tube manufacturer can
foresee long-term (or short-term) profitability where the initial demand for
a small number of tubes may be high, but rapidly falls off due to the
limited market size.  Unless the tooling and setup costs are minimal, this
doesn't appear to make good business sense, unless there's an untapped
future market waiting to be discovered!

If, in your travels or correspondence with others you happen to find one,
please let me know.  Thanks again for your reply.

-Paul, W9AC
Jacksonville, Florida


-----Original Message-----
From: Richard W. Ehrhorn <w4eto@rmii.com>
To: 'paulc@mediaone.net' <paulc@mediaone.net>; 'amps@contesting.com'
<amps@contesting.com>
Date: Monday, August 03, 1998 5:02 PM
Subject: RE: [AMPS] 3CV1500A7


>
>Greetings Paul...
>
>To the best of my recollection, Eimac decided to discontinue making the
>3CV1500A7 (actually a 3CX1000A7 with a boiler instead of air fins) some
>time in the late 70's.
>
>ETO had already switched to the "new" 8877 around 1972 but Eimac agreed to
>make one last production run for us as a "service" to our customers. We
>contacted all registered ALPHA SEVENTY owners and then committed to, I
>think, 75 tubes, most of which went directly to various 70V owners.
>
>If any of the vapor tubes have been made since then, I don't know about it.
>This all suggests that the answer to your question is that they're pretty
>doggone scarce!
>
>FYI, for a year or two in the mid-70's ETO offered a factory conversion of
>the 70V to use the 8877 with air cooling, and roughly half of all owners
>took us up on it. Think quite a few others did conversions on their own. If
>I remember
>right, all the operating parameters of the original tube (possible
>exception: a small change in the zener that determines operating bias) are
>copasetic for the 8877. Of course one also could convert to the 3CX1000A,
>but why?
>
>73,   Dick   W0ID   (ex-W4ETO)
>
>
>-----Original Message-----
>From: Paul Christensen [SMTP:paulc@mediaone.net]
>Sent: Sunday, August 02, 1998 6:14 PM
>To: amps@contesting.com
>Subject: [AMPS] 3CV1500A7
>
>
>After a long search, I have finally acquired a vapor-cooled Alpha PA-70V
>amplifier.  Can anyone tell me how obtainable the 3CV1500A7 tubes are these
>days in either NOS or good used condition?  Thanks and 73,
>
>-Paul, W9AC
>
>
>
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