[beatnik]

just got a new used amp and i have a bit of an issue, the issue i have is when i played with a decent amount of gain and had a blast through my big muff i now have this rattling sound when i play, the rattle isnt there on the clean channel with low gain but on the lead channel or with gain added to either channel the rattle is present certain notes affect it more for example 9th fret on the high e is ridiculous, from a bit of research its been suggested that it could be tube rattle does this sound right?

[polishbroadcast]

Saying what the amp is might help. If it is a physical rattle, you just have to do a bit of sleuthing. Tubes are always good candidates for rattling. Cheap baffles can rattle; loose handles, reverb tank, speaker wire laying against the cone, etc.

Make a loop of chords that rattle the amp and get a chopstick and start pressing on things that could potentially be loose.

[beatnik]

its a mesa boogie dc2 combo

[WATThouse]

Plug in your guitar, set the amp on the setting you are having problems, turn the guitar down and tap the tubes with a screw driver. If one sounds like a kick drum, you have a tube with a small piece of metal ratting around and getting amplified. This is usually a power amp tube issue. But since it is only happening on the high gain channel, it may be a preamp tube. Of course if it's a power amp tube that's the problem, you have to replace them all.

[6stings]

Check if there are things outside the amp that may resonate. I have some licence plates hanging on the walls that vibrate on some frequences, the snare drum too...

[j.s.c]

I would say that a rattle sound has 70% chance coming from the speaker's coil. You could test it with another speaker or with the clean channel at high volume, if it rattle (with some gain in clean channel) the coil can be damaged at some point.

[stevo]

I think it's tube noise since it's happening on certain notes and not others. It could be mechanical rattle from your amp chassis, but you should be able to tell easily if that's true. And the speaker question is covered above.

Note that tubes are generally liable to rattle in combos from sympathetic vibrations which occur inside the tube and come from the vibrations in your chassis when you play. This depends on the frequency and volume of the note you're playing, and can awaken all manner of reedy and otherwise rattly noise. Some tubes are worse than others and some amp stages are more prone to it than others.

When/if you go to tap your tubes to do some diagnostics, chopsticks make good tube tappers as they're less likely to damage the glass.


I could go on and on, but Mesa has a good guide for diagnosing tube issues in general:

http://www.mesaboogie.com/manuals/F-Series.pdf

[nickyboy]

I bet it nothing serious. Any update Ben?

[beatnik]

well ive tried it in different rooms to rule out anything in the room vibrating, at first i thought it was the reverb tank so i took the tank out and held it while playing the note the vibration was still there, im leaning towards it being a tube issue ill try and record a video in a minute when the kids have gone out thanks for all the suggestions so far

[6stings]

Have you tried to remove all tubes and put it on top of another amp/speaker cab?

[beatnik]

im a bit of a tube novice so havent attempted to remove them incase i cant get them back in and dont have any other cabs

[6stings]

You have to pull them out someday, beat.

[nickyboy]

as mentioned earlier..
tap them with a pencil 0 usually the culprit will make a "different" noise..possibly glow differently.
as per my txt earlier - i've got spare 12ax7 tube you can try..but haven't got any el84's. which i suspect is what u've got as pwr tubes.
if there's any major stuff going on give me a bell and i can point u towards a good nearby amp tech (who does a lot of work for jimmy page).

[stevo]

Any update? I'm on the edge of my seat...

[GretschGhost]

I know this seems like an obvious enough suggestion, but rather than moving everything around and beating on things, you could just check to make sure the tubes are seated correctly and that all of your screws, etc. are tight.

Since certain things only rattle at certain frequencies it's entirely possible that that C# you're hitting is just the right pitch to set it off.

My first thought was also the voice coil as mentioned above, but if it's not making any nasty noises when you're hitting low notes, it really doesn't sound like a blown speaker.

I've had things like loose knobs, wires touching the side of the chassis and even just an angry washer cause ridiculous amounts of noise that seemed inconceivable to be linked to the actual cause.

[beatnik]

Originally Posted by nickyboy

as mentioned earlier..
tap them with a pencil 0 usually the culprit will make a "different" noise..possibly glow differently.
as per my txt earlier - i've got spare 12ax7 tube you can try..but haven't got any el84's. which i suspect is what u've got as pwr tubes.
if there's any major stuff going on give me a bell and i can point u towards a good nearby amp tech (who does a lot of work for jimmy page).

mate perhaps soon we can get together ill bring the amp and u can help me diagnose it im leaning towards it being a power tube but not 100% sure i went in to soundwave and asked the tech in there and to be honest i know more about it than him and i know nothing big waste of time

Originally Posted by 6stings

You have to pull them out someday, beat.

i know mate and i will i just wana sort of know what im doing before i do

Originally Posted by stevo

Any update? I'm on the edge of my seat...

no closer yet mate been to see a local tech without the amp just to ask him and he wasnt very helpful

Originally Posted by GCGhost

I know this seems like an obvious enough suggestion, but rather than moving everything around and beating on things, you could just check to make sure the tubes are seated correctly and that all of your screws, etc. are tight.

Since certain things only rattle at certain frequencies it's entirely possible that that C# you're hitting is just the right pitch to set it off.

My first thought was also the voice coil as mentioned above, but if it's not making any nasty noises when you're hitting low notes, it really doesn't sound like a blown speaker.

I've had things like loose knobs, wires touching the side of the chassis and even just an angry washer cause ridiculous amounts of noise that seemed inconceivable to be linked to the actual cause.

ive checked the tubes i can get to easily and have checked all screws/reverb tank etc that i can get to without removing the amp from the cab, i do get the noise on lower notes aswel but not all notes

[GretschGhost]

Originally Posted by beatnik

mate perhaps soon we can get together ill bring the amp and u can help me diagnose it im leaning towards it being a power tube but not 100% sure i went in to soundwave and asked the tech in there and to be honest i know more about it than him and i know nothing big waste of time


i know mate and i will i just wana sort of know what im doing before i do


no closer yet mate been to see a local tech without the amp just to ask him and he wasnt very helpful


ive checked the tubes i can get to easily and have checked all screws/reverb tank etc that i can get to without removing the amp from the cab, i do get the noise on lower notes aswel but not all notes

Does it sound like an airy fart? (not trying to be funny here ) If so it's likely the voice coil as mentioned before.

If it's a rattle or strange rumble that is *amplified* by turning up the volume it is very likely a tube. The tapping test will probably isolate it, but I'd bet it's a power tube in that case.

*edit* I should also ask if there is any audible "static" or noise when the amp is just sitting silent, kind of like a subtle (or sometimes not so subtle) whooshing sound like moving water, waves, etc. This can be a bad capacitor.

[stevo]

Originally Posted by beatnik

ive checked the tubes i can get to easily and have checked all screws/reverb tank etc that i can get to without removing the amp from the cab, i do get the noise on lower notes aswel but not all notes

If you can find a friend with an amp, it would be rather easy to rule things out. Unplug your speaker and use his amp as the main speaker. If the noise disappears, you know you're getting closer, but you're still not sure where it came from. Then use his amp and plug your speaker into it and try to repeat the noise. If you get the noise, it's your speaker. If not, it's most likely tube.

I wouldn't rule out speaker, but it's not as likely since Mesa usually overrates their speakers. Unless someone used the amp as a cabinet extension, that speaker hasn't been pushed anywhere near it's limits. Even then, you can still get a blown speaker. But I don't feel it's likely. And I wouldn't know how it sounds since I've never had one.

FWIW - I get certain noises from my power tubes at times. It doesn't usually present any cause for concern. It's just mechanical coupling from the vibrations into the tube.

Also - I don't know how loud you have to turn it up to get this noise, but have you plugged the headphones into the recording jack to see if you still hear it?

[stevo]

Any update on this? We await...