Tube type question, 12JGT, 12JGT, PC86, for Thoress FF preamp.

I think you may be right, typo. I cannot find 12JGT in any of my tube books.

Why not take the cover off, see what tubes are now in the unit, and, often, markings for tube types are printed adjacent to the tube sockets. It’s doubtful they would mark it wrong on the unit.

p.s.

see page 9 of this manual, I think more evidence the early info is a typo

'The amplifier comes with six NOS tubes (2xPC86+2x12J5GT+2x12J5GT) which have been carefully selected to meet tight specifications"

http://www.thoeress.com/manuals/thoeress_preamplifier_manual.pdf

they could have said 2 of dese and 4 of dem

Removing the cover is the next step of course, the preamp is not home at the moment so i’ll look next week when it is home. I missed that near the end of the manual, thanks for pionting that out. Probably a typo then. Also wonder why they didn’t put 4x 12J5’s. 

thanks for looking up the tubes in the tube book you have,

cheers. 

This A’Gon ad explains it.

• Line Stage: 2×12J5GT vacuum tubes, single-ended zero-feedback topology for high linearity and phase integrity.

• Phono Stage: 2×PC86 + 2×12JGT tubes, purely active Moving Coil (MC) gain stage (65 dB gain @1 kHz) with passive RIAA de-emphasis, no step-up transformers.

https://www.audiogon.com/listings/lisbi5j7-thoress-ff-preamplier-tube

DeKay

If you can't use an alternate tube, give Richardson Electronics a call. If anyone is going to have your tube, it would be them.