[Dogmatrix]

I have a Tung-Sol 7236 acting up on me.
It crackles on startup and I see sparks in the tube and then settles down once it warms up.
The sound went through the headphones too but they are fine, thank god I didn’t blow a driver.
Is it time to toss this tube or will resoldering the pins help here?

Sounds like the insulation on the heaters is worn and they are arcing a little
Probably only get worse from there until it shorts out

 

[g0ldl10n]

I have a Tung-Sol 7236 acting up on me.
It crackles on startup and I see sparks in the tube and then settles down once it warms up.
The sound went through the headphones too but they are fine, thank god I didn’t blow a driver.
Is it time to toss this tube or will resoldering the pins help here?

It sparked inside the tube? You are lucky your drivers are okay, lol.. personally, I wouldn't use that tube ever again even if I replaced the solder in the pins.. I have had the unfortunate event of where one of my drivers did not survive on my headphones.. thankfully, they got covered by their warranty, but this was from an input.. I just called it game over for it lol

 

[triod750]

I always use sacrificial headphones until the tubes have settled on startup. @mordy taught me this. I also pry my octals loose from sockets with a screwdriver. This saves sockets in amp and adapters. Being careful pays off.

 

[attmci]

Try the 1266, solid like a tank. Lol

 

[Gemini88]

Has anyone pulled one of these tubes from an old piece of equipment, besides an audio amplifier?
I'm curious about what these tubes were specifically used for. This information seems to be pretty scarce. Here's what I've found so far:
The Tung-Sol 7236 was allegedly used in the SAGE radar system in the power supply for the tape drives. That number ending in 9999 on the tube base was supposedly assigned by IBM, who built SAGE and many of the other early computers. I read some articles and watched some old videos about SAGE but couldn't verify this info. Supposedly the 7236 is an improved version of the 5998A, which is supposed to be a 5998 in a different glass envelope. Comparing the 3 tubes you can see how they became more vibration resistant with each iteration. I've seen 5998As with IBM labelling but haven't seen any IBM 7236s yet. I don't really know much about how tube amplifiers work but it seems that in SAGE or in a headphone amplifier these tubes are used to provide a very precise electrical output based on a given input.

The 6080WB was probably used in guided missiles. Overall that's why these super heavy duty tubes were developed but I couldn't find much about the 6080WB in particular. It was was built to withstand 300 G of acceleration and I believe it was intended to continue functioning uninterrupted during that time. It's also built to function at 60,000 feet of altitude. The graphite plates are one of the most obvious differences but they were also made with a special type of glass and the area where the metal pins exit the glass at the bottom is reinforced with a type of epoxy or similar material. On mine if you look down inside the tube you can see a light green material. The use of ceramic instead of mica in the spacers was also a big deal at the time. The high price of these tubes is nothing new, even in the 60s they would have cost many times the price of a regular 6080. It seems that sound quality was never a consideration but these were designed to be the best 6080s money could buy and accurate signal reproduction must have been a high priority. There's a book about the history of the Bendix Red Bank tubes. Unfortunately the 6080WB is only mentioned very very briefly. I believe the book says Bendix licensed other manufacturers to produce these tubes in order to keep up with the demand.

With JAN tubes like 5998A or 5998 you can find suppliers in the aerospace industry still selling them. The number starting with 5960-00-XXX-XXXX is the part number and appears on some of the boxes. Out of curiosity I sent in a few RFQs but this doesn't seem like a way to save any money. Here's a quote I received for one 5998 (5960-00-617-8955):

 

[g0ldl10n]

Has anyone pulled one of these tubes from an old piece of equipment, besides an audio amplifier?
I'm curious about what these tubes were specifically used for. This information seems to be pretty scarce. Here's what I've found so far:
The Tung-Sol 7236 was allegedly used in the SAGE radar system in the power supply for the tape drives. That number ending in 9999 on the tube base was supposedly assigned by IBM, who built SAGE and many of the other early computers. I read some articles and watched some old videos about SAGE but couldn't verify this info. Supposedly the 7236 is an improved version of the 5998A, which is supposed to be a 5998 in a different glass envelope. Comparing the 3 tubes you can see how they became more vibration resistant with each iteration. I've seen 5998As with IBM labelling but haven't seen any IBM 7236s yet. I don't really know much about how tube amplifiers work but it seems that in SAGE or in a headphone amplifier these tubes are used to provide a very precise electrical output based on a given input.

The 6080WB was probably used in guided missiles. Overall that's why these super heavy duty tubes were developed but I couldn't find much about the 6080WB in particular. It was was built to withstand 300 G of acceleration and I believe it was intended to continue functioning uninterrupted during that time. It's also built to function at 60,000 feet of altitude. The graphite plates are one of the most obvious differences but they were also made with a special type of glass and the area where the metal pins exit the glass at the bottom is reinforced with a type of epoxy or similar material. On mine if you look down inside the tube you can see a light green material. The use of ceramic instead of mica in the spacers was also a big deal at the time. The high price of these tubes is nothing new, even in the 60s they would have cost many times the price of a regular 6080. It seems that sound quality was never a consideration but these were designed to be the best 6080s money could buy and accurate signal reproduction must have been a high priority. There's a book about the history of the Bendix Red Bank tubes. Unfortunately the 6080WB is only mentioned very very briefly. I believe the book says Bendix licensed other manufacturers to produce these tubes in order to keep up with the demand.

With JAN tubes like 5998A or 5998 you can find suppliers in the aerospace industry still selling them. The number starting with 5960-00-XXX-XXXX is the part number and appears on some of the boxes. Out of curiosity I sent in a few RFQs but this doesn't seem like a way to save any money. Here's a quote I received for one 5998 (5960-00-617-8955):

That is a quote for a single TS 7236?

 

[Gemini88]

That is a quote for a single TS 7236?

A single TS 5998. 650 dollars!

 

[g0ldl10n]

Has anyone pulled one of these tubes from an old piece of equipment, besides an audio amplifier?
I'm curious about what these tubes were specifically used for. This information seems to be pretty scarce. Here's what I've found so far:
The Tung-Sol 7236 was allegedly used in the SAGE radar system in the power supply for the tape drives. That number ending in 9999 on the tube base was supposedly assigned by IBM, who built SAGE and many of the other early computers. I read some articles and watched some old videos about SAGE but couldn't verify this info.

The 7236 was built as a long life service as power amplifier for computer service per its datasheet, and by the 1960s, IBM was producing 70% of the worlds computers, it would make sense these would have been used by IBM.

 

[mordy]

The 7236 was built as a long life service as power amplifier for computer service per its datasheet, and by the 1960s, IBM was producing 70% of the worlds computers, it would make sense these would have been used by IBM.

Can you count the 7236s?

 

[Gemini88]

Recently I bought two untested Chatham Electronics JAN CAHG 6AS7G, one looks normal and this is the other. Those aren't just black lines across the getter filaments, they're actually cut or broken. The getter flashing looks about the same as the other tube so I'm not too concerned but wondering if this is common on the old D getter tubes

 

[Gemini88]

Can you count the 7236s?

There are some old videos about SAGE on YouTube, I kept pausing them trying to get a good look at the tubes!

 

[triod750]

https://www.ebay.com/itm/265664706544?hash=item3ddad9b7f0:g:mQUAAOSwP9ZiaQmJ

At least you get a pair and the plates are black. What more could you ask for?

 

[Gemini88]

I recently purchased a Bendix 6080WB with slotted graphite plates and felt extravagant spending almost $130 on a 6080 tube, but $2000 for a pair is insane! I wonder how they sound though...

It's funny how the metal plate ones cost more than the graphite plates.

 

[gibosi]

Recently I bought two untested Chatham Electronics JAN CAHG 6AS7G, one looks normal and this is the other. Those aren't just black lines across the getter filaments, they're actually cut or broken. The getter flashing looks about the same as the other tube so I'm not too concerned but wondering if this is common on the old D getter tubes

I have three pairs, plus a pair of 6520, and none have broken getters. I think you must be very lucky and got something very special. lol

 

[triod750]

Everything with that seller is 'funny'. Or not. I remember when I felt extravagant when I paid more than $10 for a tube.