Mesa 6L6 tube problem

[Hairy Wonder]

I bought two mesa branded 6L6GC tubes to replace the old ones in my rectoverb combo but I noticed a sort of rattling come from the amp after I made the switch. The rattle doesn't seem to be coming from the speaker, I am almost positive it is a physical component rattling somewhere in the chassis of the amp. I took the new tubes out again to look at them and noticed that the 7th pin on one of them was not properly soldered.

pic
http://imgur.com/HcoPp

Could this be problematic? The other 3 6L6 tubes that I own have correctly soldered pins.

Thanks for your help
-Hairy

 

[shytfayse]

If the element inside the tube was not soldered properly to the pin, the tube would probably not operate. Just beause the solder does not come all the way out to the end of the pin does not mean the solder connection is bad. There is quite a bit of solder blobbed up inside those pins. Can you push a needle up through the entire pin until it hits the glass? This looks like pin 7 which would be the heater. Does the filament light up? Does it go on and off?

There are quite a few sources of rattle in a combo amp. Mechanical: loose speaker baffle, loose speaker, loose transformer, etc... Tube rattle: This is where the elements inside the tube are loose and resonate while the amp is being played. IMO, new tubes should not rattle. Old tubes can get this way from heating and cooling lots of times and from just being banged around. Some combo amps are more prone to this because of the way they are designed - are the tubes getting pounded by the speaker?, does the amp resonate because of the wood used/tuned frequency of the box, etc...

Do this whilst playing: 1) Go to the back of the amp. 2) Place your hand on some of the passive items above. 3) Place your finger on the tip of each output tube (yes, it will be warm). If doing this stops or significanly reduces the rattling sound you have probably found it. Your hand or finger provides dampening for the resonation.

I hope you find it. - Pat.

 

[stokes]

If it doesnt rattle with the old tubes and does rattle with the new tubes,it is the tubes.Tube rattle in current production tubes is more common than with old stock tubes.It really has nothing to do with a combo amp rattling the tubes to death by design,it has to do with current production tubes being built like crap.Dont know where you got the tubes,but you should send them back,they arew faulty.

 

[Hairy Wonder]

Thanks for the replies, I found the rattle to be coming from that tube with less solder on its 7th pin, but I tried swapping it into the other tube socket and it rattles much less. It only rattles when I play a low G and the rattle is inaudible on my recordings, so I'm not too concerned about it.

 

[stokes]

The rattle has nothing to do with that pin you think is not soldered correctly.Pin 7 is one of the heater supply connections and the tube would not function if it wasnt connected.It is more likely being caused by a loose component in the tube that is in the signal chain,plate or grid.It will not get better and will likely get worse as the tube ages.It is defective,you paid money for a broken tube,I would get it replaced.

 

[OryCheyne]

Thanks for the info in this older post. Although Topic Heading should have been 'Rattling Valves' would have been easier to find.

I recently found one of the power tubes in my new mkV went all rattling once I got to push the volume up above 4. Once pushed the valve stayed busted. It is too annoying to leave as is, so I'll need to get a new pair, I'll probably use standards.

When I say 'new' mkV I mean 5yo. It was sitting in the shop for 5 years before I picked it up.

I do think that the combo probably does shake the borderline ones into an early grave. Anyone with a mark combo knows these little things can get so loud it really does feel like something is going to break. Scary Loud! Thankfully just busting my valves.

 

[Markedman]

Anyone with a mark combo knows these little things can get so loud it really does feel like something is going to break.

That made me think of the old MESA/Boogie picture of a factory shot where someone in the background is whacking a chassis with a hammer.

 

[mesaboogie6L6]

If you think that little amp is loud, just ask the guys who have Mark II, III Coliseum 1X12 180 watt combo's with EVM12L's.

 

[OryCheyne]

This post is getting a bit old but I wanted to mention I replaced my rattling 6L6. I purchased a matching pair of 440 yellows. Unfortunately my markV sounds like *** now and will swap back the one with the rattle time permitting in the next few days to make sure it's the tubes. I got a good 4 hours out of the new valve, but now that I think of it, I was probably ripped off. Would be good if Mesa could package their tubes so that you need to destroy the package to get the tubes out.

mesaboogie6L6, seeing you mentioned asking Coliseum owners what the true meaning of loud is, and seeing that you appear to own one. I'm asking if you can share any cool gossip about things you may have broken with your Coli? 180watts sounds insane. Have you cracked any windows or maybe push some friendships too far?

 

[mesaboogieKT88]

Sorry about the delayed response, I forgot my password and the password reset DOES NOT WORK! I had to set up a new profile.

I haven't cracked out any windows, when I first got my amp and got in a band, the other guitar player was overwhelmed with my Coliseum and 800 watt EVM12L loaded 4X12 Mesa cab. He was playing a Crate half stack, he then upgraded to an Ampeg Lee Jackson, then after 3 years he upgraded to a Mesa Triple Rev G. with a Mesa 4X12 with C90's.

 

[bandit2013]

Many tubes will sing, caused by change in electric field of the materials. This self resonance or piezo vibrations may also be ringing out in the glass itself. Sometimes as tube age due to use, the expansion of the materials due to heat will slightly change the physical dimensions of parts that do not have the same coefficient of expansion. Eventually the tubes will start vibrating in response to the electric field changes in the tube. Sometimes the singing tube can be loud enough to be very annoying when playing at low volume. I have had some really good sounding tubes do this as well as bad ones.

I believe that JJ or Eurotubes has silicone doughnuts that you place over the tube to be used as a damper to the vibrations. Not sure if it works. But I know I can quite a singing or rattling tube with my finger at the tip but it will be hot (not as hot as the sides).