15 Jun
2020
15 Jun
'20
6:51 a.m.
While going through my assortment of old vacuum tubes looking for audio
treasures, I found a handful of IBM branded ones. Mostly 5965, but
there's one 5963 mixed in.
These are dual triodes with the same pinout as common small-signal audio
tubes such as 12AX7/7025/ECC83, but characteristics closer to 12AT7 or
12AU7. My RCA Receiving Tube Manual says they're designed to withstand
being held in cutoff for long periods of time, and mentions digital
applications.
Anyone know what kind of IBM machine these would have been used in?
15 Jun
15 Jun
7:03 a.m.
Hard to say, without the modules they came from.
As far as my (limited) understanding of vacuum tube logic goes, double triodes were very
common for implementing basic boolean logic functions. Therefore, most IBM vacuum tube
computers and data processing machines would have hundreds/thousands of similar
dual-triode tubes making up the logic.
Basically, they could be out of any vacuum tube machine made by IBM. IBM 600 and IBM 700
series machines being the most likely.
On Jun 15, 2020, at 2:51 PM, Guy N. via cctalk
<cctalk at classiccmp.org> wrote:
While going through my assortment of old vacuum tubes looking for audio
treasures, I found a handful of IBM branded ones. Mostly 5965, but
there's one 5963 mixed in.
These are dual triodes with the same pinout as common small-signal audio
tubes such as 12AX7/7025/ECC83, but characteristics closer to 12AT7 or
12AU7. My RCA Receiving Tube Manual says they're designed to withstand
being held in cutoff for long periods of time, and mentions digital
applications.
Anyone know what kind of IBM machine these would have been used in?
16 Jun
16 Jun
7:58 a.m.
On Mon, 2020-06-15 at 10:24 -0400, William Donzelli wrote:
Good question. They have an IBM logo and "Made in USA", along with the
part number (5965 or 5963) and a bunch of numbers that might give a hint
as to manufacturer. Any suggestions on how to decode them?
These came to me from my father, who worked in the Vacuum Tubes
department at GE for a while when I was growing up, so there's a good
chance the OEM was GE.
While going
through my assortment of old vacuum tubes looking for audio
treasures, I found a handful of IBM branded ones. Mostly 5965, but
there's one 5963 mixed in.
Who made them?
17 Jun
17 Jun
8:11 a.m.
On Tue, 2020-06-16 at 11:04 -0400, William Donzelli wrote:
Sure! I'd attach a picture, but....
On the top of the tubes are numbers printed in yellow. A couple typical
ones are C392 and C152.
On the side, the large IBM logo is flanked by groups of numbers, an
example:
62-39 64-17 IBM 317261
188-5 MADE IN U.S.A.
This is one of the more legible ones. The two pairs of numbers on the
first line at the left appear to vary, the 188-5 and 317261 seem to be
constant; but it's hard to be certain.
The obvious part number 5965 has some other markings that are
overprinted by the IBM logo and numbers. It looks like it could be:
5965
A
U.S.A
..
..
The pattern of dots is hard to make out because of "IBM" on top of it.
The structure inside is a "long-plate" type, with three horizontal ribs.
I haven't had a chance to compare the structure to any of the many old
dual-triode, medium-mu tubes in my assortment. There might be some
clues. It wouldn't surprise me if these were a fairly standard design
with some changes to the cathode to withstand being held in cutoff for
long periods of time.
Good question.
They have an IBM logo and "Made in USA", along with the
part number (5965 or 5963) and a bunch of numbers that might give a hint
as to manufacturer. Any suggestions on how to decode them?
What are the numbers?
Details, man! 
8:27 a.m.
They are indeed GEs! 188 is the clue.
--
Will
On Wed, Jun 17, 2020 at 11:14 AM Guy N. via cctalk
<cctalk at classiccmp.org> wrote:
On Tue, 2020-06-16 at 11:04 -0400, William Donzelli wrote:
Sure! I'd attach a picture, but....
On the top of the tubes are numbers printed in yellow. A couple typical
ones are C392 and C152.
On the side, the large IBM logo is flanked by groups of numbers, an
example:
62-39 64-17 IBM 317261
188-5 MADE IN U.S.A.
This is one of the more legible ones. The two pairs of numbers on the
first line at the left appear to vary, the 188-5 and 317261 seem to be
constant; but it's hard to be certain.
The obvious part number 5965 has some other markings that are
overprinted by the IBM logo and numbers. It looks like it could be:
5965
A
U.S.A
..
..
The pattern of dots is hard to make out because of "IBM" on top of it.
The structure inside is a "long-plate" type, with three horizontal ribs.
I haven't had a chance to compare the structure to any of the many old
dual-triode, medium-mu tubes in my assortment. There might be some
clues. It wouldn't surprise me if these were a fairly standard design
with some changes to the cathode to withstand being held in cutoff for
long periods of time.
Good
question. They have an IBM logo and "Made in USA", along with the
part number (5965 or 5963) and a bunch of numbers that might give a hint
as to manufacturer. Any suggestions on how to decode them?
What are the numbers?
Details, man!
22 Jun
22 Jun
4:56 a.m.
Thanks! What is the secret decoder ring that tells you 188 means GE?
EIA manufacturer codes. These were often applied to private and house
branded labelled tubes. Other numbers are 274 for RCA, 280 for
Raytheon, 158 for DuMont, and so forth.
EIA codes were used for non-tube electronic parrots.
--
Will
4:58 a.m.
An electronic parrot in the vacuum tube days? -- must have been very large!
On 22/06/2020 07:56, William Donzelli via cctalk wrote:
--
Nigel Johnson
MSc., MIEEE, MCSE
VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
You can reach me by voice on Skype: TILBURY2591
If time travel ever will be possible, it already is. Ask me again yesterday
This e-mail is not and cannot, by its nature, be confidential. En route from me to you, it
will pass across the public Internet, easily readable by any number of system
administrators along the way.
Nigel Johnson <nw.johnson at ieee.org>
Please consider the environment when deciding if you really need to print this message
Thanks! What
is the secret decoder ring that tells you 188 means GE?
EIA manufacturer codes.
These were often applied to private and house
branded labelled tubes. Other numbers are 274 for RCA, 280 for
Raytheon, 158 for DuMont, and so forth.
EIA codes were used for non-tube electronic parrots.
--
Will 
16 Jun
16 Jun
8:13 a.m.
Mosyt likely GE.
"IBM did the final assembly, but more than 400 companies supplied parts and
subassemblies for its computers, including GE for vacuum tubes and 3M for magnetic tapes.?
(https://www.computerhistory.org/revolution/early-computer-companies/5/111)
On Jun 16, 2020, at 4:58 PM, Guy N. via cctalk
<cctalk at classiccmp.org> wrote:
On Mon, 2020-06-15 at 10:24 -0400, William Donzelli wrote:
Good question. They have an IBM logo and "Made in USA", along with the
part number (5965 or 5963) and a bunch of numbers that might give a hint
as to manufacturer. Any suggestions on how to decode them?
These came to me from my father, who worked in the Vacuum Tubes
department at GE for a while when I was growing up, so there's a good
chance the OEM was GE.
While
going through my assortment of old vacuum tubes looking for audio
treasures, I found a handful of IBM branded ones. Mostly 5965, but
there's one 5963 mixed in.
Who made them?
8:41 a.m.
GE did not make many tubes for IBM except for some made for SAGE devices.
--
Will
On Tue, Jun 16, 2020 at 11:38 AM Camiel Vanderhoeven via cctalk
<cctalk at classiccmp.org> wrote:
Mosyt likely GE.
"IBM did the final assembly, but more than 400 companies supplied parts and
subassemblies for its computers, including GE for vacuum tubes and 3M for magnetic tapes.?
(https://www.computerhistory.org/revolution/early-computer-companies/5/111)
On Jun 16, 2020, at 4:58 PM, Guy N. via cctalk
<cctalk at classiccmp.org> wrote:
On Mon, 2020-06-15 at 10:24 -0400, William Donzelli wrote:
Good question. They have an IBM logo and "Made in USA", along with the
part number (5965 or 5963) and a bunch of numbers that might give a hint
as to manufacturer. Any suggestions on how to decode them?
These came to me from my father, who worked in the Vacuum Tubes
department at GE for a while when I was growing up, so there's a good
chance the OEM was GE.
While
going through my assortment of old vacuum tubes looking for audio
treasures, I found a handful of IBM branded ones. Mostly 5965, but
there's one 5963 mixed in.
Who made them? 
17 Jun
17 Jun
10:14 a.m.
On Tue, Jun 16, 2020 at 07:58:14AM -0700, Guy N. via cctech wrote:
the part number (5965 or 5963)
Ah, good ol' 5965s.
These were a higher-spec version of ... some really common tube which I
no longer remember. The Bendix G-15 was wholly based on them. I probably
have one or two around the house since I kept one-of-each of the plug-in
cards when my high school scrapped it. (It would have been too heavy
even for *me* to haul around all these years.)
I still have the technical manual, complete with the FE's hand-written
annotations.
mcl
10:24 a.m.
Ah, good ol' 5965s.
These were a higher-spec version of ... some really common tube which I
no longer remember. The Bendix G-15 was wholly based on them.
5965 is a computer rated 12AV7 with better balanced cutoff
characteristics, but generally worse for noise.
About 15 percent of the tubes in a G15 are 6197s, which are computer
rated 6CL6s.
--
Will
21 Jun
21 Jun
6:22 a.m.
On Wed, 2020-06-17 at 13:24 -0400, William Donzelli via cctalk wrote:
5965 is a computer rated 12AV7 with better balanced
cutoff
characteristics, but generally worse for noise.
Darn. "Worse for noise" probably means I won't find audio nirvana
trying these in any of my amps. And there's a good chance they're worn
out anyway (one of my theories is that these are tubes that were
undergoing reliability testing or failure analysis).
3:22 p.m.
On 6/22/2020 5:58 AM, William Donzelli via cctalk wrote:
See that is the problem ... Snake oil tends to develop a hiss
after a while, not the valve.
Ben.
Darn.
"Worse for noise" probably means I won't find audio nirvana
trying these in any of my amps.
Most computer tubes are pretty bad for audio, even though there are
plenty of snake oil tube dealers that proclaim them as audio gold.
--
Will
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18 comments
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