Spring Retainer causing tubes to crack....

Bassoballs · #1 11-14-2011, 06:25 PM

My SVT-2 Pro recently had a tube failure. Upon inspection I noticed the spring retainers were causing the glass to chip at the point where the spring attaches to the retainer. Four of the Six were chipped. One had actually developed a crack in the glass. Has anyone on here experienced this before?

WingKL · #2 11-14-2011, 06:28 PM

Yes, I destroyed 2 expensive Mullard CV4004's that way(ouch). They were the best sounding 12ax7 types I've heard. I think it depends on the tube though, other tubes may be more durable if the glass up top is thicker.

Bassoballs · #3 11-14-2011, 06:30 PM

For what its worth, they were Winged=C=

**B-string** · #4 11-14-2011, 06:32 PM

Bend the tab where the spring attaches out and away from your tubes (will also provide some additional tension).
Note your amp tech SHOULD have done this.

Bassoballs · #5 11-14-2011, 07:50 PM

Bending the retainers would not work, as they are extremely flimsy. As for my tech, I work part time at Metropoulos Amplification (heritage B-15s were designed and built here) so all the basics have been covered. We simply have never experienced this type of situation before.

**B-string** · #6 11-14-2011, 08:04 PM

Quote:

Originally Posted by Bassoballs

Bending the retainers would not work, as they are extremely flimsy. I actually work part time at Metropoulos Ampflification (The Heritage B-15's were designed and built here). None of us have ever experienced this before.

Your kidding right? Even the Russian replacements I have used could be reformed without breakage. If you have built the Heritage B-15s you should have been aware of the springs riding too close to the glass? Between metal and glass, metal will always win. Maybe get some better quality retainers, they are much cheaper than tubes.

grendle · #7 11-14-2011, 08:05 PM

Just take em off, you really don't need them, especially if their causing damage. You can always bend the tube leads in slightly for a tighter fit in the socket.

Bassoballs · #8 11-14-2011, 08:34 PM

Quote:

Originally Posted by grendle

Just take em off, you really don't need them, especially if their causing damage. You can always bend the tube leads in slightly for a tighter fit in the socket.

They were removed as soon as I realized the problem.

T-Bird · #9 11-14-2011, 10:01 PM

Hi.

I'm relatively young, and have experience about tube amps only from the late 80's but I have never heard or seen that happen. Even with badly deformed rings that contact the glass in only two points.

Could You be kind enough to take a pic or a two?

Personally, I would never remove the retainers, nor would I be comfortable to use a tube amp that gets moved around without 'em.

Regards
Sam