Retubing.

[ibanezjunkie]

well, i have a blackheart head, as some of ou may know (i did alot of asking around) and i wanna get ready for retubing it when the chinese stock tubes die.

the music store in hitchin sells groovetubes only. so i have a question..

replacing the chinese EL84 with a GT-EL84R doesnt need rebiasing right? and the same question about the 12AX7 and the GT-12AX7R

cheers in advance

[duhvoodooman]

From what I've read, the BH Little Giant is cathode-biased and so would not need rebiasing when changing the power tube.

BTW, as far as I know, Groove Tubes is not a tube manufacturer but rather buys, tests and rebrands tubes from various sources. So replacing that Chinese EL84 with a GT tube could mean putting another Chinese EL84 in it! To be fair, though there are some really crappy tubes coming out of China, there are some very good ones, too. Personally, I'd be pulling the stock tube and holding it as a back-up and install one of JJ's excellent EL84's (https://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=3&sub_category_id=18).

[ibanezjunkie]

From what I've read, the BH Little Giant is cathode-biased and so would not need rebiasing when changing the power tube.

BTW, as far as I know, Groove Tubes is not a tube manufacturer but rather buys, tests and rebrands tubes from various sources. So replacing that Chinese EL84 with a GT tube could mean putting another Chinese EL84 in it! To be fair, though there are some really crappy tubes coming out of China, there are some very good ones, too. Personally, I'd be pulling the stock tube and holding it as a back-up and install one of JJ's excellent EL84's (https://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=3&sub_category_id=18).


that looks fine, and sounds pretty easy if i just pull out the stock and stick in a JJ. what about the preamp tube though?

[tunghaichuan]

DVM is correct on both counts.

The LG is a cathode biased amp, so rebiasing when changing out the power amp tube is not strictly necessary. It is the same case for the preamp tube, also cathode bias, so no rebiasing necessary.

GT is a rebrander/tester. They get tubes from the same sources that everyone else does, China, Russia, Slovakia, et al. and test them.

I believe the suffix on the end of the tube designation is where the tube is made: R for Russia, S for Slovakia, and C for China. The GTEL84-R is probably the same tube as the Sovtek EL84. The GTEL84-S is probably the same one made by JJ Tubes in Slovakia.

tung

[markb]

What Tung said. Groove Tube tubes are graded and tested. Try Watford Valves or Hot Rox for more choice.