how does one identify an unknown tube?

pucho812 · Mar 8, 2010

MY buddy picked a tube he thought was an old RCA 6l6. It's not. It does have the same 8 pin base and the plates look like an RCA 6l6 but the pin configuration inside is different. It has no markings on it other then RCA on the base. So is there any way to really figure out what kind of tube it is or should I just have him junk it?

mad.ax · Mar 8, 2010

Sometimes taking a picture with the flash on makes the marking appear.
You may also try with an UV light...

Axel

MagnetoSound · Mar 8, 2010

It might be a 7027.

schmidlin · Mar 8, 2010

I've done this a few times. You can trace the pin-to-element visually inside the tube. With your pin-out configuration, open the back of your trusty tube manual and scan for the right match. Then test for the varying options. It takes a little time, tho.

CJ · Mar 8, 2010

put it in the freezer, then take it out and blow on it, the label might magically appear like something out of a sherlock holmes movie,

sometimes not,

just get the heater pins and scan the large octals, they did not make that many,

put 6 volts on the heater, if it glows, you only need to look at all the 6xxx tubes.

unless its a 5881, a 7027, or a 6550, im jus sayin...

pucho812 · Mar 9, 2010

once again I can always find useful info in this place to fill in the gaps in my audio knowledge. thanks guys

drpat · Mar 10, 2010

mac · Mar 12, 2010

My wife will definitely know that i have completely lost it!!

Tubes in the freezer ...... brilliant

;D

gemini86 · Mar 12, 2010

mac said:
My wife will definitely know that i have completely lost it!!

Tubes in the freezer ...... brilliant

;D

it's supposed to make them sound better also... you know, cryo-treated tubes are the bees knees in the audiophile world now.

tv · Mar 12, 2010

And I thought that cooking strings then putting them in the freezer was the most ultimate hi-tech ...

pucho812 · Mar 12, 2010

gemini86 said:
mac said:

My wife will definitely know that i have completely lost it!!

Tubes in the freezer ...... brilliant

;D

Click to expand...

it's supposed to make them sound better also... you know, cryo-treated tubes are the bees knees in the audiophile world now.

anything that will drive up the price...

how does one identify an unknown tube?

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