Tubes Going Bad?

[Musical123]

Hi,

I have a Mesa SOB 1x12 combo and I think the pre-amp tubes are going bad. My tubes are from Mesa and are around 1 year old.

When I hit a harmonic, even at low volume, sometimes I get a sound like someone is lightly hitting a wine glass at a rapid rate. I assume that this is a pre-amp tube since this happened in the past and was corrected when I swapped one of them out.

My questions are:

Why do I keep needing to replace tubes?

Is there a way to secure the tubes better so they do not vibrate as much (right now they are held in place by a metal cover which uses a spring to hold the tube in place)?

Do you think this is a pre-amp tube?


Thanks

 

[Boogiebabies]

Sounds like power tube rattle. Does the combo have SUS-4 mounts ?

 

[stokes]

+1 on the power tube rattle,try tapping each tube with a pencil or something,not something heavy like a screwdriver and see if you can locate the problem tube,then go get some good tubes.Those tube shields are about the best to hold the tubes in place.IMO,vibrations will only hurt a tube if the tube was poorly made to begin with.I have an Ampeg Gemini from the '60's that was used for bass for about 5 years and it still has the original Bugle Boy pre tubes,no tube sheilds or shock mounts of any kind.This whole "combo amps eat tubes" was never heard of till they started making tubes like crap.If a combo ate tubes like some people think,why would combos have become so popular?I believe Mesa takes the precaution with the shock mounted chassis because they know the tubes made today suck.

 

[Musical123]

Thanks for the replies. I will look into this.

What do SUS-4 mounts look like?

 

[stokes]

Just to clarify,when I said to tap the tubes,I was referring to the preamp,quite often power tube rattle will only appear when the tube is driven with a signal,tapping wont always cause the rattle.The sus-4 mounts are rubber washer like mounts inside the holes in the top of the cab where the screws hold the chassis.