Hi Arno,
I would prefer you send me a photo of a 4CX800A7.
Neither Alpha nor Acom amps have 4CX800 tubes built in, all are GU74b.
I can design you a datasheet with whatever you like to include within 15
minutes.
I am quite familiar with the Eimac nomenclature, also with JEDEC and ours in
Europe of course..
73
Peter
_____
From: N7KA@comcast.net [mailto:N7KA@comcast.net]
Sent: Montag, 15. Februar 2010 22:17
To: DF3KV
Subject: Re: [Amps] Tentec Titan 425 with GU74-B????
Peter
What Carl says about a GU-74B may be correct. However the ALPHA 99 which
was produced in Bulgaria had what was called 4CX800A tubes. I have a DATA
SHEET from SVETLANA I got a few years back that is for a 4CX800A (dated
3/98). Ask the owners of an ALPHA 91 or 91B what tube is in their amps and
most likely originals will be 4CX800A. I do not have the 4CX800A in a file,
only a paper copy so can not send it to you..
Here is a reference of a USA supplier:
http://www.rfparts.com/tubespecs.html go down the list to 4CX800A and see
it has GU-74B shown also.
Guess its the old auto thing: The English call it a bonnet, in the USA we
call it a hood. You know, that metal thing that lifts up to expose the
motor of a front engined auto/car/ride.
The tube numbering system that is/was used by EIMAC: here is a quote from
an EIMAC Catalog about the numbering system: "EIMAC tube types are
identified by either a non-descriptibe sequentially-assigned 4-digit type
number, standardized and registered with the ELECTRONICS INDUSTRIES
ASSOCIATION (EIA), for non-duplicationthroughout the world, or by a coded
numbering system, designed to convey descriptive information about the tube.
Many tube types can be identified with either number, and are brancded with
both.
Take as example the ever so common work horse: 8877 also known as the
3CX1500A. Branding would appear as 3CX1500A7/8877 where the 8877 is the EIA
Type Number. Reference Page 5 of VARIAN (EIMAC) POWER GRID TUBE CATALOG
2267/101 10,000 4/92. This 177 page catalog only cost $5.00 in 1992 and
I find it is worth its weight in gold.
But back to the 4CX800A. See the May 1996 QST article written by George
Daughtrs (then AB6YL) that gave info to convert a DENTRON MLA2500 from 2ea
EIMAC 8875 to to a single SVETLANA 4CX800A. Yes take ot a pair of triodes
and put ina tetrode by adding a screen and grid supply pljus some other
circuit changes.
They even had a DATA SHEET for a 3CX800A7. The SVETLANA catalog and many
data sheets show them using the 3CX**** or 4CX**** type number.
My TEN TEC TITAN 425 uses 2ea EIMAC 3CX800A7, my ALPHA 76A uses 3ea EIMAC
8873, and my ALPHA 77S uses 2ea EIMAC 3CX1500A7/8877. Even have a new pair
of EIMAC 3CPX800A7 tubes on the shelf. I like TRIODES.
Arne N7KA
----- "DF3KV" <df3kv@t-online.de> wrote:
>
>
Hi Arne,
Svetlana does not make a 4CX800A7 and never did.
Please show me one.
OK, in the past they produced GU74b
73
Peter
>
_____
From: N7KA@comcast.net [mailto:N7KA@comcast.net]
> Sent: Montag, 15. Februar 2010 17:09
> To: DF3KV
> Subject: Re: [Amps] Tentec Titan 425 with GU74-B????
Peter
I am sure you have several replies. SVETLANA makes 4CX800A7 (GU-74B).
4CX800A7 is a standard nomenclature numbering system that defines a tube,
believe its IEA format.
Arne N7KA
> ----- "DF3KV" <df3kv@t-online.de> wrote:
> > What is a 4CX800?
> > Was never made...
> > But it is true, tetrodes can not replace triodes without a major
redesign
> > 73
> > Peter
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