Slight Rattling

[Artmusic]

i am hearing a slight rattling inside my LSC when playing lower notes. When I tap the 6L6's I can hear the same rattling sound. Is a tube replacement in order? Is this sound just something to expect in a LSC. I just got the amp new, but it is last years model.
Thanks,
Art

 

[SixVeeSix]

Could be tubes, could be the speaker or?... Try plugging into a different speaker. Try swapping in a spare tube - you do have spares don't you? Have a friend make the rattle happen and see if you can muffle it. Careful, output tubes are hot, use a kitchen hot pad. You will find it.

 

[clutch71]

Is it a head or a combo? Does it occur at any volume range? Combo's are prone to rattling. There are bands you can buy to help limit this. If it's happening even at low volumes could be the tubes.

 

[Artmusic]

Thanks, it is a combo, 1x12, it happens at moderate volumes. I havn't gotten to crank it up yet. I can make the exact same sound by tapping the power tubes, it sounds just like when you have a light bulb that is shot. That slight gingle, that is the sound I hear when I tap the tubes. The power tubes. The amp sounds fine, just this rattling thing going on.
Art

 

[recto-robbie]

Hello, ive run into this slight problem numerous times on different combos. Its simply loose internals of your tubes. Some tubes seem to have tighter fitting insides than others. I havent really noticed any particular brand worse than others. Its pretty much a crap shoot.
A simple test is to simply hold each one of your power tubes near your ear and shake. If you hear loose metallic rattle sounds in the tube like what you would hear in a blown light bulb, you found the trouble tube.
Theres really not much you personally can do unless you are the one who actually hand picks the tubes you will use in your combo.
You will notice that at certain volumes and when playing certain notes you will hear this rattling in your combo. I believe at certain frequencies your combo rattles just right allowing you to hear the tube rattles.

You can try solving this problem with some tube dampeners. I have some for el34's and 6l6's and believe it or not they do seem to work pretty well. Id honestly say they stop about 90% of all rattling you may hear. I bought from the guys sight I provided below and everything has been good. I will add that if you read the descriptions of these dampers on his sight it states that they make the sound even better,, I didnt notice any improvement at all with the sound but they did help with the rattling.
Give them a try, they are pretty cheap anyways and remember to find the correct size for the tubes your using them with and good luck to ya.

http://cgi.ebay.com/VACUUM-TUBE-AMP-DAMPER-EL34-6CA7-KT77-6L6WGB-DAMPENER_W0QQitemZ220159623388QQihZ012QQcategoryZ64629QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[212Mavguy]

Your power tubes have likely developed a case of microphonics. Combo amps shake the tubes and that shaking plus heating and cooling expansion/contraction of the elements inside over time all lead to it. You might find that you hear that more when playing alone than when playing in a mix.

One way to help at least a little bit is to put something heavy on top of the amp, like a sandbag or something like that, the increased mass will damp the cabinet vibrations some. Anything to keep the chassis and tubes from vibrating as much will help a bit. I have a modified Fender silverface champ that can put out up to 15 watts depending on what power tube is in it, and I used to put it upside down on the floor, that helped. There is a reason why very old guitar amps had the tube chassis resting in the cabinet bottom... If the tubes are old, consider replacing them and plan on that same condition occurring again over time. I agree with the other post that says some tubes are better about resisting microphonics than others. I use vintage old stock tubes in my amps and frankly am not up on which modern production power tubes are best for resisting microphonics since I don't purchase them. Hope other posters can help in modern tube purchase selections...

 

[Artmusic]

I've been checking the amp today, It makes the rattling noise when playing a low G, or even a mid G. I can tap on top of the amp and hear the same noise, but everything I can reach is tight. it almost seems like the amp chassis is rattling inside of the combo itself. Any ideas would be welcome.
Art

 

[recto-robbie]

Seriously friend, just take out each power tube one by one when they are cold and gently shake them near your ear. If you hear loose filaments inside the tube,, you know which one it is.
Another way to check is to hit that G chord or note and slightly put pressure on each power tube without burning yourself. Once you find the right tube that rattling sound will go away when you put some pressure on it. Trust me ive been through this before. Matter of fact, the first tube amp I ever owned was the peavey valveking and I bought and replaced the amp 3 times over because of this same problem.
I thought for sure the amp chassis had some rattle, tightened every scew I could find,, on and on and on. I eventually bought a boogie f50 and it had the same **** problem. I eventually figured it out, that the tubes sometimes have loose insides. Mesa even replaced a pair because I told them it was rediculous. Some tubes have it, some you cant hardly hear at all and some dont have any rattle,, its the luck of the draw.
The rattles you speak of I believe, are not typical tube microphonics where you actually hear the rattling or noise through your speakers,, Right? What you hear is the loose filaments inside the tubes,, if you crank your amp loud enough, im sure you wont hear these rattles. Keep the amps volume low like I play often at home and there it is again.... Right?

 

[recto-robbie]

Hey I forgot,,, someone mentioned that your tubes have become micophonic which is possible. I will tell you first hand that the next time you buy tubes you will have a good chance of having more tubes straight out of the box with the same rattles. Most people dont notice this problem I assume because most people who have tube amps have the volume up to band levels most of the time. Other than the slight noise nothing will happen to your amp,, its no big deal unless you cant deal with the actual noise. Ive even found that once you find the tube with the loose filaments,,, try swapping it to a different spot,, sometimes the noise isnt as bad because the new spot has less vibration or you may find that it doesnt rattle on a G note,,, it may be an A or something instead.
Good luck, really its no big deal,, or buy a head like me

 

[Artmusic]

Thanks again for the input. I am hearing what you are saying. I actually replaced my power tubes last night only because I wanted the EL's instead of the 6L6's. That being said, I checked each tube before replacing and none had the rattling sound. At first i thought that is was the tubes, I can tap the top of the amp while the power is off and hear the rattling. I put pressure on all the tubes and tapped the top. Same rattle. I tried putting pressure on the tube retention things that goaround the base of the tube and that did help slightly. I think it must be inside the amp itself. Playing softer or louder doesn't really make a difference unless I play really softly. It happens more with my Les Paul than with my strat, but its still there. I wish I could figure this out. I love the way this amp sounds, the rattle not withstanding. Of course, if I play really loud, I can drown it out, but that's not fixing the problem.
Art

 

[yettoblaster]

My Mark I Re-Issue did the exact same thing when fully warmed up with the STR-440 6L6's that it came with.

It's just physical noise.
They have a lot of plate area so vibrations from the speaker gets to 'em pretty quickly.
I think they'll go a ways before it causes any real problems, but it IS disconcerting. Sounds like it could blow at any seam.

I use 6V6's mostly, and EL-34's. Neither of those give me any problems.

 

[clutch71]

So the rattling still occurs with the EL34's installed?

 

[yettoblaster]

Not mine.
Only 6L6 STR 440's.

 

[Artmusic]

Yes, the rattling is still there with the EL's. It really sounds like something in the amp itself. Very wierd.

 

[yettoblaster]

Maybe try an extension cab with the combo's onboard speaker muted?
Could help you isolate something. Or maybe not.
My rattles got worse the more the tubes warmed up.

 

[lyman]

i've got the same thing going on with my maverick, even though it's a head. it sort of sounds like an amplified lightbulb filament rattle but also has a hiss/spitty character. i'm going to try putting something for dampening between the bottom of the head and top of the cab. oddly, mine too is more pronounced with a low G.