Can somebody identify who made this 12AU7 ?

[AC439]

I have an old 12AU7 and the prints on it are almost gone. I would like to know what is the manufacturer of this tube. I have been googling images to no avail.

The prints are yellow and the first 3 letters of the text appears to be "bro...".

 

[JMFahey]

It might be a remarked tube, very common for commercial reasons.

Not REALLY important, just test it, if it works fine, it works.

Some people obsess on brands, as in "xxx is brighter, yyy is warm and middy, zzz is strong and bold" and similar superstition.
No such thing.

Just test it and you tell us 🙂

 

[jdarg]

I'm no tube guru but i happen to have a ton of 12au7 tubes. That looks like sylvania judging by the plate shape and the ribs. Check ebay you will see what i mean. Sylvania used yellow print for a time as well as green.

 

[ferret]

That's an Electro-Harmonix. The "bro" is actually "tro"

Electro-harmonix12AU7 - Google Search

 

[AC439]

Thanks for all replies. My goad is pure and simple - just want to know the manufacturer of this working tube.

I compared the EH pictures to my tube. The fonts are different and the spacing between the "b" and "r" on my tube space out further. Also, the bottom part of the letter "b" is more complete unlike the letter "t" in the EH tube, which looks like a hook.

I followed the lead of yellow print Sylvania but for all the pics I found, the prints are all in caps. The letters on my tube are in lower case.... Still scratching my head .......

I also heard some tubes were made specifically for broadcast industry so "bro..." could very well be "broadcast" ???

 

[mctavish]

That's an Electro-Harmonix. The "bro" is actually "tro"


No. look at the pins. That is an American made tube, probably Sylvania. I have many with that plate structure and the most are either GE or Sylvania.

 

[ferret]

Thanks guys, I stand corrected. I have not had many USA made valves to hand. Had EH, Sovtek, Ei, Philips, Teonex, ... have two very old NOS Mullards

 

[Mark Tillotson]

That's an Electro-Harmonix. The "bro" is actually "tro"

Electro-harmonix12AU7 - Google Search

Nope, definitely a 'b' not a 't', the character outline is clearly visible.

 

[maton00]

Yeah maybe the "bro" is from "hasbro" like the toys, not that it wouldnt rock in a guitar amp just like any other 12au7 tube, there is nothing to worry about.
If you are into treasures and the like, there are just waiting in the local museum......
Returning to the topic, it looks like sylvania maybe a remarked label there were tons of them, such things are long gone.