[macdane]

If you inserted the JJ 6SN7 with the keyway properly oriented, this should not have happened!   Typically,  JJ uses thinner-than-standard contact pins on their tubes.  This results in a looser than normal fit.  My guess is that you may have forced the tube in incorrectly, jamming the keyway in, but out of its groove.

Very interesting. Over the years, I've used 3-5 different brands of each type of tube in these amps. Other than these new JJ 6SN7s, my new JJ 5Y3s are easily the tightest fitting tubes I've used ... and the 6SN7s are MUCH tighter. Meanwhile, the JJ 2A3-40 is the loosest fitting 2A3 I've used.

In any case, I managed to get that stubborn tube out. I wrapped it in several layers of cotton fabric for protection and pried gently between the tube base and socket with a thin but stiff plastic spatula on each side. I'll be away from these amps for the next week but will try to follow up with more info soon.

Thanks for the help!

[mresseguie]

macdane,

This may sound odd, but I'm glad you suffered this issue....because I am a tube noob and I've had this fear/concern in the back of my mind that says, "What if a tube gets stuck?"
Now I know what to try.

Thank you for posting this thread. 

Michael

[jea48]

I've had a pair of Wright WPA-3.5 amps for 15+ years without a lick of trouble, but I'm still a total tube neophyte.

My wife bought me a new set of JJ tubes (2A3, 6SN7 & 5Y3 per amp) for Christmas and I expected this to be as simple as every other time I've swapped tubes. Not so. The tubes arrived yesterday and I found both 6SN7s and 5Y3s to be incredibly tight — difficult to seat fully in the sockets — while the 2A3s slip in so loosely I think a stiff breeze could blow them over. Right out of the box, everything sounded pretty good over the course of several hours of listening.

When I powered up the amps today, I got 2-3 seconds of music before the right channel died. I powered off again to check all of my connections, and the sound came back for maybe a second. After confirming all cable connections, I powered on again with the same result: the right channel amp only played for about 2 seconds, then again briefly when I turned it off.

I decided I'd swap my previous set of NOS tubes back in so I could listen a bit and then dig into this problem at a later date, but I now I can't get the 6SN7 tube out of that right channel amp. Any good advice for removing extraordinarily tight-fitting tubes without damaging anything?

Thanks,
Dane

 while the 2A3s slip in so loosely I think a stiff breeze could blow them over.

When I powered up the amps today, I got 2-3 seconds of music before the right channel died. I powered off again to check all of my connections, and the sound came back for maybe a second. After confirming all cable connections, I powered on again with the same result: the right channel amp only played for about 2 seconds, then again briefly when I turned it off.

JMHO, your problem is the loose contact pressure between the tube pins and tube socket contacts on the 2A3 tube. The tube socket contacts have lost their memory tension.  Probably not only the poor contact pressure but corrosion on the tube socket contacts. Another problem to make matters worse the diameter of the pins on the new 2A3 might be smaller than the older tube it replaced.

Jim

[galyons]

... I managed to get that stubborn tube out. I wrapped it in several layers of cotton fabric for protection and pried gently between the tube base and socket with a thin but stiff plastic spatula on each side. I'll be away from these amps for the next week but will try to follow up with more info soon.

Thanks for the help!

Congrats! Well done!