Identification and value of GE 12AX7 tubes

[Aviv]

Hi all,

I would like to ask for your assistance in making sure I have properly identified the tubes I have (see the attached pictures). Per my understanding, these are:

standard GE 12AX7 tubes
Short gray plate
O-getter
made in the USA (188-5 GE plant in Owensboro)
Date code JM means June 1978


Did I get it properly?
I have few NOS sleeves, what would be a reasonable price per tube, assuming tested?

Thanks,
Aviv.

 

[mondogenerator]

I have some of these in my guitar amp, (also Brimar of unknown age, and Mullard Short Plate Blackburn 1965)

There seemed to be little to zero interest on ebay, for even the Mullard

 

[DAK808]

People have the notion that the ax7 with long plates are better than the short plate variety. So, that is what is preferred in vintage tubes. I am pretty sure that the long plate GE ax7 fetches a better auction price than the short plate, all things being equal.

 

[mondogenerator]

My interpretation is that subjectively hifi folk seem to prefer long plate, and guitar players short plate.

Technically I'm not sure there's much to choose between.

It merely as valuable as the price you can sell it for.