By the way... Richardson Electronic sells the 8873 at 731$ (on order).
73
Tony, I0JX
"Antonio Vernucci" ha scritto nel messaggio =
...
I recently inquired EIMAC about 8873 and 8875. This was the answer:
Dear Antonio: thank you for your request.
Eimac still makes the 8873 tube; however we stopped making the 8875 tube =
several years ago.
The 8873 tube is available through our distributor, Richardson =
Electronics. Their website is
www.rell.com. They can give you price and =
delivery information.
Please let me know if there is anything else you need.
Regards,
Linda Di Lorenzo
Eimac Marketing Dept.
Problem is that the 8873 is very expensive. On the other hand the =
cathode current of the 4CS250R is by far lower than that of the 8873. =
Two 4CS250R would hardly replace a single 8873.
If you have access to a mechanical workshop, perhaps you may succeed =
modifying the external plate of a (much more common) 8874 so that the =
plate salvaged from a faulty 8873 fits on it.
73
Antonio, I0JX
--=20
------------------------------------------------------
Antonio Vernucci, I0JX US call: K0JX
50-MHz beacon: 50.004 KHz FSK 10W 5/8 vertical antenna
home page:
http://www.qsl.net/i0jx
e-mail: k0jx {at} amsat {dot} org
------------------------------------------------------
"G.Beat" ha scritto nel messaggio =
news:LXK%c.709$MQ5.705@attbi_s52...
"cpstelecom.co.uk" wrote in message=20
...
Hi,
I need a 8873 tube for my heathkit linear, none of the usual UK =
dealers=20
have
one in stock. I have found a few suggestions to mod the amp to a =
forced=20
air
cooled tube but I hate the sound of fans in the shack.
--=20
Steve H
Remove the spam to reply.
=20
Steve -
=20
The 8873 (the conduction version of the 8874 triode) is rare (no =
longer in=20
production) and usually premium dollar when they do appear. The only =
other=20
conduction (not forced air) tube that MAY be adopted to this design is =
one=20
of the 4CX250 family of tubes that are still in production
=20
The 8560AS (or Eimac 4CS250R), Motorola used this tube in its Micor =
base=20
amplifiers for a number of years. The prices for surplus tubes are =
$75 to=20
$100. Photo of Motorola amp:
http://www.uslink.net/~jcomm/2Mamp.html
=20
It is a tetrode, instead of the triode 8873 (Mullard YL-1321 may be=20
equivalent; I have seen Y799 and Y808 in UK to refer a similar tube)
http://www.cpii.com/eimac/catalog/80006.htm
=20
There is also VERY GOOD news that Svetlana is making an 8560AS (so =
tube=20
supply and production is much better)
http://www.svetlana.com/docs/products/metal/8560AS.html
=20
Index
http://www.g8wrb.org/
=20
There has been a fair amount of discussion about conversions of the =
SB-230=20
amplifier (e.g. using Russian GI7b triode; standard 8874 conversion) - =
but=20
most of these have been extensive modifications for forced air. I do =
agree=20
with you that if you are going to convert this amplifier - stay true =
to the=20
quiet operation (no fan) desired by original design.
=20
I would recommend a proper control board, such as Ian White's (G3SEK)=20
Tetrode Boards (2)
http://www.ifwtech.co.uk/g3sek/board.../tetrode-2.htm
=20
Of course a 6 meter or 2 meter conversion could occur at the same time
http://www.geocities.com/PatBillDavis/Amplifiers.html
=20
w9gb
=20
=20