6973 tubes found on ebay at a decent price

http://tinyurl.com/8a5gw9

Rich Klestinez wrote:
http://tinyurl.com/8a5gw9




Rick, those look too short to be proper 6973 tubes. The plates on my
original Sylvania 6973s are 2.9cm (1-1/8") long, whereas this picture
shows a plate that is under 2.1cm (7/8") a difference of almost 30% .

That means they likely can't dissipate the heat as well the original...

John :-#(#

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"Old pinballers never die, they just flip out."

On Jan 6, 10:44*am, John Robertson wrote:
Rich Klestinez wrote:
http://tinyurl.com/8a5gw9

Rick, those look too short to be proper6973tubes. The plates on my
original Sylvania 6973s are 2.9cm (1-1/8") long, whereas this picture
shows a plate that is under 2.1cm (7/8") a difference of almost 30% .

That means they likely can't dissipate the heat as well the original...

John :-#(#


Ok, further research shows that these are indeed the tubes sold as
replacement 6973s so they appear to be proper, just a smaller plate
than the originals.

John :-#)#
--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

John:
You have a good point, I was curious about that also. Called New Sensor
800-633-5477 to find out what up. Seems that the original 6973 was a short
tube, other manufacturers chose to make them larger then went back to making
them shorter again. A search of the tube manuals that I have shows the
"outlines" in the GE manuals as a short tube, and, later they show it as a
large tube, then my 1982 GE tube manual shows it as a short tube again.
anyway I have been using those tubes in all the SHFA series amps ( as well
as Wurlitzer's) that I do for my customers and they have performed well. So
far after 2 years I have not gotten any back for warranty. They seem to
test identical to the original ones on my TV-7 tube tester. Can't say that
for those abortive 7199's they made though.

cheers
Rich
In Texas USA

wrote in message
...
On Jan 6, 10:44 am, John Robertson wrote:
Rich Klestinez wrote:
http://tinyurl.com/8a5gw9

Rick, those look too short to be proper6973tubes. The plates on my
original Sylvania 6973s are 2.9cm (1-1/8") long, whereas this picture
shows a plate that is under 2.1cm (7/8") a difference of almost 30% .

That means they likely can't dissipate the heat as well the original...

John :-#(#


Ok, further research shows that these are indeed the tubes sold as
replacement 6973s so they appear to be proper, just a smaller plate
than the originals.

John :-#)#
--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

wrote:
On Jan 6, 10:44 am, John Robertson wrote:
Rich Klestinez wrote:
http://tinyurl.com/8a5gw9
Rick, those look too short to be proper6973tubes. The plates on my
original Sylvania 6973s are 2.9cm (1-1/8") long, whereas this picture
shows a plate that is under 2.1cm (7/8") a difference of almost 30% .

That means they likely can't dissipate the heat as well the original...

John :-#(#


Ok, further research shows that these are indeed the tubes sold as
replacement 6973s so they appear to be proper, just a smaller plate
than the originals.

John :-#)#
--


I got a nice letter from the suppliers of these Electro-Harmonix tubes
that explains the apparent difference in the two tubes (E-H vs Sylvania)
as follows:

The plate structure of the Electro-Harmonix 6973 has a larger diameter
than the vintage 6973, which had a plate structure similar to a 6AQ5.
The actual mass of the plate structure of both tubes is about the same.
We have not had any problems with heat dissipation or wattage with the
Electro-Harmonix 6973. Be aware that there are NOS vintage 6973 tubes
being sold that are actually relabelled 6CZ5 tubes. Actual 6973 tubes
have a screen grid connection to pins #1 and #8. A 6CZ5 has a screen
grid connection only at pin # 1. The extra screen grid connection on
the 6973 aids in heat dissipation from the screen grid and allows for
symmetrical layout of the circuit (as found in some hi-fi equipment).

Glad that is cleared up, and these tubes look like a good deal for someone!

John :-#)#


--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

Rich Klestinez wrote:
John:
You have a good point, I was curious about that also. Called New Sensor
800-633-5477 to find out what up. Seems that the original 6973 was a short
tube, other manufacturers chose to make them larger then went back to making
them shorter again. A search of the tube manuals that I have shows the
"outlines" in the GE manuals as a short tube, and, later they show it as a
large tube, then my 1982 GE tube manual shows it as a short tube again.
anyway I have been using those tubes in all the SHFA series amps ( as well
as Wurlitzer's) that I do for my customers and they have performed well. So
far after 2 years I have not gotten any back for warranty. They seem to
test identical to the original ones on my TV-7 tube tester. Can't say that
for those abortive 7199's they made though.

cheers
Rich
In Texas USA

Hi Rich,

See my latest reply to the original thread:

Electro-Harmonex has addressed my concerns about their 6973s to my total
satisfaction.

John :-#)#


wrote in message
...
On Jan 6, 10:44 am, John Robertson wrote:
Rich Klestinez wrote:
http://tinyurl.com/8a5gw9
Rick, those look too short to be proper6973tubes. The plates on my
original Sylvania 6973s are 2.9cm (1-1/8") long, whereas this picture
shows a plate that is under 2.1cm (7/8") a difference of almost 30% .

That means they likely can't dissipate the heat as well the original...

John :-#(#


Ok, further research shows that these are indeed the tubes sold as
replacement 6973s so they appear to be proper, just a smaller plate
than the originals.

John :-#)#
--

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."