Help identifying old set of 12ax7a

[EOengineer]

I’m helping a friend sort out an old Kalamazoo 12 from the 60s and I couldn’t help but notice these old tubes.

As far as I’ve found CMI could be anything, they rebadged from many manufacturers. Anyone have a good eye for tubes?

 

[FuzzyAce]

Possibly Mullard? But don't take my word for it as I'm not as well versed as many gurus.

 

[EOengineer]

Possibly Mullard? But don't take my word for it as I'm not as well versed as many gurus.

Same boat. Saw they were made in the UK and instantly thought maybe mullard. I’m not usually that lucky but the guy who owns the amp is.

 

[FuzzyAce]

Same boat. Saw they were made in the UK and instantly thought maybe mullard. I’m not usually that lucky but the guy who owns the amp is.

It probably is but just keep digging if you have to know.

 

[Achilles]

?????

CMI amplifiers, acoustic guitars, bass guitars, electric guitars

Information about the CMI brand with details and specifications of amplifiers, acoustic guitars, bass guitars, electric guitars made by CMI. CMI amplifiers, acoustic guitars, bass guitars, electric guitars for sale.

www.guitar-list.com

 

[unix-guy]

Careful inspection of the images shows these are CMI Electronics... Printed on the tube.

From searching it appears they may have been Raytheon as the actual manufacturer and CMI might be Chicago Musical Instrument company...

 

[EOengineer]

?????

CMI amplifiers, acoustic guitars, bass guitars, electric guitars

Information about the CMI brand with details and specifications of amplifiers, acoustic guitars, bass guitars, electric guitars made by CMI. CMI amplifiers, acoustic guitars, bass guitars, electric guitars for sale.

www.guitar-list.com

Careful inspection of the images shows these are CMI Electronics... Printed on the tube.

From searching it appears they may have been Raytheon as the actual manufacturer and CMI might be Chicago Musical Instrument company...

Yeah I think in both cases anything branded CMI in the tube space is probably manufactured by someone else. I’m not a tube expert by any stretch, but I don’t see anything pointing towards any in-house tube manufacturing.

I appreciate you guys poking around. I just sent the pics to my amp tech.

 

[la szum]

I’m helping a friend sort out an old Kalamazoo 12 from the 60s and I couldn’t help but notice these old tubes.

As far as I’ve found CMI could be anything, they rebadged from many manufacturers. Anyone have a good eye for tubes?

View attachment 27748
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Date codes look very Mullard-esque to me. B = Blackburn Factory produced.

Tube enthusiast: know your tube codes. - Effectrode

My recent visit to the Mullard Blackburn factory got me interested in identifying the origin of the few Mullard tubes I own. The factory, date of manufacture and revision of a particular tube can be determined from a code that’s etched into the side of the glass envelope (the colour of the...

www.effectrode.com

 

[6CA7-A]

Relabled Blackburn [with codes] Mullard ECC-83 / 12AX7's.