Hi,

I need a 8873 tube for my heathkit linear, none of the usual UK dealers have
one in stock. I have found a few suggestions to mod the amp to a forced air
cooled tube but I hate the sound of fans in the shack.
--

Steve H

Remove the spam to reply.



---
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"cpstelecom.co.uk" wrote in message
...
Hi,

I need a 8873 tube for my heathkit linear, none of the usual UK dealers
have
one in stock. I have found a few suggestions to mod the amp to a forced
air
cooled tube but I hate the sound of fans in the shack.
--

Steve H

Remove the spam to reply.


Steve -

The 8873 (the conduction version of the 8874 triode) is rare (no longer in
production) and usually premium dollar when they do appear. The only other
conduction (not forced air) tube that MAY be adopted to this design is one
of the 4CX250 family of tubes that are still in production

The 8560AS (or Eimac 4CS250R), Motorola used this tube in its Micor base
amplifiers for a number of years. The prices for surplus tubes are $75 to
$100. Photo of Motorola amp:
http://www.uslink.net/~jcomm/2Mamp.html

It is a tetrode, instead of the triode 8873 (Mullard YL-1321 may be
equivalent; I have seen Y799 and Y808 in UK to refer a similar tube)
http://www.cpii.com/eimac/catalog/80006.htm

There is also VERY GOOD news that Svetlana is making an 8560AS (so tube
supply and production is much better)
http://www.svetlana.com/docs/products/metal/8560AS.html

Index
http://www.g8wrb.org/

There has been a fair amount of discussion about conversions of the SB-230
amplifier (e.g. using Russian GI7b triode; standard 8874 conversion) - but
most of these have been extensive modifications for forced air. I do agree
with you that if you are going to convert this amplifier - stay true to the
quiet operation (no fan) desired by original design.

I would recommend a proper control board, such as Ian White's (G3SEK)
Tetrode Boards (2)
http://www.ifwtech.co.uk/g3sek/board.../tetrode-2.htm

Of course a 6 meter or 2 meter conversion could occur at the same time
http://www.geocities.com/PatBillDavis/Amplifiers.html

w9gb

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

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

"Antonio Vernucci" wrote in message
...
By the way... Richardson Electronic sells the 8873 at 731$ (on order).

73

Tony, I0JX

================================

As $ 731 it is definitely not economicial for the radio amateur -- maybe
health care or military !

w9gb

You could buy two SB230's for that much!!
I have 3 of them that I will one day sell. One of them is on 6, so I want to
gather up enough pennies to purchase a PW1.
....Dave
"G.Beat" wrote in message
news:zmM%c.1383$MQ5.1112@attbi_s52...

"Antonio Vernucci" wrote in message
...
By the way... Richardson Electronic sells the 8873 at 731$ (on order).

73

Tony, I0JX

================================

As $ 731 it is definitely not economicial for the radio amateur -- maybe
health care or military !

w9gb

Well I see that it is FOB from the LaFox warehouse just north of me !
http://catalog.rell.com/rellecom/scr...6632&PNO=&PNM=

gb

"Antonio Vernucci" wrote in message
...
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




--
------------------------------------------------------
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
...
Hi,

I need a 8873 tube for my heathkit linear, none of the usual UK dealers
have
one in stock. I have found a few suggestions to mod the amp to a forced
air
cooled tube but I hate the sound of fans in the shack.
--

Steve H

Remove the spam to reply.


Steve -

The 8873 (the conduction version of the 8874 triode) is rare (no longer in
production) and usually premium dollar when they do appear. The only
other
conduction (not forced air) tube that MAY be adopted to this design is one
of the 4CX250 family of tubes that are still in production

The 8560AS (or Eimac 4CS250R), Motorola used this tube in its Micor base
amplifiers for a number of years. The prices for surplus tubes are $75 to
$100. Photo of Motorola amp:
http://www.uslink.net/~jcomm/2Mamp.html

It is a tetrode, instead of the triode 8873 (Mullard YL-1321 may be
equivalent; I have seen Y799 and Y808 in UK to refer a similar tube)
http://www.cpii.com/eimac/catalog/80006.htm

There is also VERY GOOD news that Svetlana is making an 8560AS (so tube
supply and production is much better)
http://www.svetlana.com/docs/products/metal/8560AS.html

Index
http://www.g8wrb.org/

There has been a fair amount of discussion about conversions of the SB-230
amplifier (e.g. using Russian GI7b triode; standard 8874 conversion) - but
most of these have been extensive modifications for forced air. I do
agree
with you that if you are going to convert this amplifier - stay true to
the
quiet operation (no fan) desired by original design.

I would recommend a proper control board, such as Ian White's (G3SEK)
Tetrode Boards (2)
http://www.ifwtech.co.uk/g3sek/board.../tetrode-2.htm

Of course a 6 meter or 2 meter conversion could occur at the same time
http://www.geocities.com/PatBillDavis/Amplifiers.html

w9gb

"Dave Edwards" wrote in message
...
You could buy two SB230's for that much!!
I have 3 of them that I will one day sell. One of them is on 6, so I want
to
gather up enough pennies to purchase a PW1.
...Dave
It looks like a nice amp apart from the tube, what happened to the 8873? a
conduction cooled amp is ideal for phone, no noisy fan. I'm looking at a
8874, removing the cooling fins and replacing with a block of copper.

Steve H


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.756 / Virus Database: 506 - Release Date: 08/09/04

Be VERY CAREFUL with BeO (Beryllium Oxide) - which is used to heatsink an
8873.
If you are unfamiliar with this material (e.g. dust, filing, milling this
material), please read appropriate harzardous material handling precautions.
Aquick google.com search should provide you necessary UK and safety
precautions.

gb


"cpstelecom.co.uk" wrote in message
...

"Dave Edwards" wrote in message
...
You could buy two SB230's for that much!!
I have 3 of them that I will one day sell. One of them is on 6, so I want
to
gather up enough pennies to purchase a PW1.
...Dave
It looks like a nice amp apart from the tube, what happened to the 8873? a
conduction cooled amp is ideal for phone, no noisy fan. I'm looking at a
8874, removing the cooling fins and replacing with a block of copper.

Steve H


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.756 / Virus Database: 506 - Release Date: 08/09/04