I recently put a Tung-Sol 12AX7 in the V1 position of my JSX head. Everything was ok until I decided to test the outcome of putting it in various positions.
When I tried to remove the tube from V1, it was very difficult. The tube was stuck in there. I finally managed to get it out and put it in V2.
Powered up the amp, and I was getting no sound at all. I switched it to V3 (which is the fx loop and active eq I think) and I was getting sound. But as soon as I engaged the FX loop, the sound was gone.
Do I have a faulty tube? I see its filament light up a bit but not as much as my other preamp tubes.
that tube has a spiral filament encased in the plate structure, it won't glow as brightly as other tubes. That being said, there is a problem with Russian made spiral filament tubes when used in cathode follower positions. V1 is not a cathode follower. But I am unsure of the other positions in your amp. Many times, particularly with Mesa amps, the tube will fail almost immediately when placed in a cathode follower position (as in V4 in my Heartbreaker, for example).
Hope this helps.
_________________ When Gibsons are outlawed, only outlaws will have Gibsons
Si Gibsons proscriptae soli proscript habebit Gibsons
I would try it in V1 again and see the result. I believe V3 is the Cathode Follower stage in the JSX (maybe Enzo can confirm). One time I put a Sovtek LPS in the V3 spot of my JSX and the tube failed almost immediately.
I didn't care for the Tungsol 12AX7 in V1 of my JSX. It was too bright and a little noisy. The absolute best I've found to use are JJ ECC83S's in V1,V2,&V3 and a Russian tube in V4, either a Sovtek or EH.
Tube manufacturers generally provide 60 day warranty.
_________________ PAF Classic Series Tube Kit.......Created By Classic30inCincy Majic Mojo Tradename..........Created By Classic30inCincy Graduate Of Joe Friday / Dragnet School Of Correspondence Doctorate Degree Diplomacy From Royal Order Possum Lodge
Users browsing this forum: No registered users and 11 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum