Roadking Tube goes "Cigerette Lighter"

[konstantine RK]

Ok,

I was noticing some plank plank planky sounds coming out instead of the usual "Zeeung chung chun" when hitting those F-A major barred chords we all use to test drive our cabs. So I play with my tube selector and switched pentode to triode on the EL34's. Nope the planks were still sticking out of the amp. I switched it back to pentode.

I look through the Roadking steel vent in front and see one of my JJ's EL34's (closest to the output transformer) is glowing like a hotplate inside! I turned off the amp.. grabbed my glove and took it out. Now earlier in the week I did break a plastic key off one of the matched EL34 tubes.. so I carefully matched the spokes to the sockets and all was well... but the tube that lit up was not that one.

Put in the Mesa EL 34's and all is well... to tell you the truth.... I may stick with Mesa since I like the sound but messing with these JJ's you can hurt your amp even if you are careful and mean to take all necessary precautions... both of these JJ's EL34's were labled 38 in the bias point


whew on this cause we have a new bassist auditioning the very next day!

 

[screamingdaisy]

I've had tubes redplate for two reasons;

Mechanical failure of the tube, and

Poor fit in the tube sockets.

It's been awhile, but I believe that JJ uses thinner pins than other tubes. This gave me problems in my old Mark III because the tube sockets were over 20 years old and stretched to accommodate Sovtek pins. The JJ's pins wouldn't fit tightly so they'd randomly redplate... usually when vibrated.

Like I said though, it's been awhile and it could've been another tube brand that was giving me problems in my Mark III... but I'm pretty sure it was JJ.

 

[konstantine RK]

but if they "redplate" as you said... are they garbage?