MT15 bottom plate/underside rattling when put on cab

[Goran Lorencin]

Hi there, any experience with dampening/fixing the bottom plate of the amp to make the rattling sound (a metal on metal sound) stop when put on a cab and playing riffs?

thx in advance

 

[László]

Hi there, any experience with dampening/fixing the bottom plate of the amp to make the rattling sound (a metal on metal sound) stop when put on a cab and playing riffs?

thx in advance

I’d try putting the amp on something that will isolate the amp from the vibrations from the cab. It might be something as simple as sitting the amp’s feet on a mouse pad, or some dense foam.

There are specialized isolation pucks, but they’re fairly expensive.

I’ve had amps whose tubes rattled due to cab vibrations, and my ‘fix’ was to take them off the cab and put them on a table. Easiest thing. Least hassle.

 

[Goran Lorencin]

Yes, the easiest solution would be to not let it rest on top of the cab, but it is so impractical space wise (if you don't have a table fitting snugly above the cab). Is that how the amp is made, do all of them have this issue? And for that matter, how problematic is the vibration coming from the cab to the amp and tubes, is that a thing to have in mind or is it negligable? It probably varies from cab to cab as they resonate differently, I understand, but I am just asking, as most of players have the head on the cab when playing.

 

[László]

Yes, the easiest solution would be to not let it rest on top of the cab, but it is so impractical space wise (if you don't have a table fitting snugly above the cab). Is that how the amp is made, do all of them have this issue? And for that matter, how problematic is the vibration coming from the cab to the amp and tubes, is that a thing to have in mind or is it negligable? It probably varies from cab to cab as they resonate differently, I understand, but I am just asking, as most of players have the head on the cab when playing.

Every situation is different. I generally keep my amps on the cabs, but they're larger 2x12 cabs that tend for whatever reason to vibrate less than 1x12s. Maybe their weight and length keeps them more stable. I have no idea!

It's my belief - and this is shared by some amp builders I've spoken with - that the closer the amp is to the speaker, the more vibration becomes a problem. However, in your situation, isolation seems to me to be the key.

When I've used tables in my studio, I don't put them next to the cab unless that's more convenient for a given session. I simply run a longer speaker cable (and I have some as long as 50 feet!). Lots of pro session players I know (I'm in the recording biz) put a speaker cab on a riser or stand, and the amp on the floor or on a chair.

I wouldn't get hung up on the idea of the head having to sit on, or above the cab, but that's probably just my opinion. If your head is vibrating enough to cause buzzing, it can't be good for the electronics.

I use these to isolate my studio monitors from the speaker stands, and they're great, but I haven't needed to isolate my amp heads from the cabs they sit on, so I can't say how they work for that.

https://isoacoustics.com/iso-puck/

 

[Goran Lorencin]

I also have a 2x12 cab with two V30 in it, but I suppose it comes down to the construction of the cab and the type of "wood" used in the construction that defines the final resonance of the top of the cab (where we usually put the head). And those iso pads aren`t cheap will look for a solution with bit longer speaker cables and a different location where to put the amp.

 

[Deleted member 5962]

I also have a 2x12 cab with two V30 in it, but I suppose it comes down to the construction of the cab and the type of "wood" used in the construction that defines the final resonance of the top of the cab (where we usually put the head). And those iso pads aren`t cheap will look for a solution with bit longer speaker cables and a different location where to put the amp.

I use either foam pads or neoprene just to isolate the amp a bit from the vibrations of the cab.

 

[László]

I also have a 2x12 cab with two V30 in it, but I suppose it comes down to the construction of the cab and the type of "wood" used in the construction that defines the final resonance of the top of the cab (where we usually put the head). And those iso pads aren`t cheap will look for a solution with bit longer speaker cables and a different location where to put the amp.

Yeah, the IsoAcoustics stuff is expensive. Best I've found so far, though. I've spoken with the owner of the company, who's a former studio designer for CBC, the Canadian Broadcasting Company; he knows his stuff.

As with studio monitors on stands or tables, it works the same way for guitar speaker cab isolation from structural vibration transmitted through the floor or furniture a speaker sits on (I've actually tried that), but I don't know if it's good for the type of vibration that might make amp heads rattle. Seems like it oughta be, I just haven't had the occasion to experiment with it.

As DTR says in his post above, neoprene mouse pads might be worth a try. I've used them to isolate heads from cab vibrations - in fact, I do that with my HXDA. But I wasn't getting rattling, I'm just paranoid that the constant vibration might somehow damage my amp unless it's damped.

 

[Deleted member 5962]

Yes, I've had no issues with my amps sitting on cabs, I just added the neoprene pads to avoid ever having any issues.

 

[Goran Lorencin]

Yeah, the IsoAcoustics stuff is expensive. Best I've found so far, though. I've spoken with the owner of the company, who's a former studio designer for CBC, the Canadian Broadcasting Company; he knows his stuff.

As with studio monitors on stands or tables, it works the same way for guitar speaker cab isolation from structural vibration transmitted through the floor or furniture a speaker sits on (I've actually tried that), but I don't know if it's good for the type of vibration that might make amp heads rattle. Seems like it oughta be, I just haven't had the occasion to experiment with it.

As DTR says in his post above, neoprene mouse pads might be worth a try. I've used them to isolate heads from cab vibrations - in fact, I do that with my HXDA. But I wasn't getting rattling, I'm just paranoid that the constant vibration might somehow damage my amp unless it's damped.

Of course! Mouse pads! How clever, you could even put another surface like a wooden board on top of two or three mouse pads placed in a row, so that you have a bigger, uniform space. I suddenly have a few ideas. But I understand that those amp feet isolators work well as they let the cab resonate more as there is less surface dampening.

On a side note, how do you connect your speaker cab to your MT15 or alike. I have a 2x12 Celestion V30 cab and it has a switchable connection 1x120 W on 8 Ohm (left channel/mono) to 2x60 W on 16 Ohm (L+R "stereo") and I am running it on 2x16 Ohm "stereo" as my speakers are 16 Ohm each. On the back of MT15 there are outputs for a single 1x16 Ohm on a dedicated jack out, and on the other two jack outs there is the 2x16 Ohm option for "stereo" and 1x8 Ohm for mono. So I should be able put a single cable from any of those two "optional" jack outs on the amp to the L/mono input on my speaker(1x 8 Ohm), am I getting this right?

 

[Deleted member 5962]

8 ohm out from the amp> 8 ohm mono input on the cab.

 

[alantig]

8 ohm out from the amp> 8 ohm mono input on the cab.

Although if I go to my 4x12, it's 16 out > 16 mono in.

 

[Deleted member 5962]

yeah, you're not going to probably ever... or at least soon, use the "stereo" inputs.

 

[László]

Of course! Mouse pads! How clever, you could even put another surface like a wooden board on top of two or three mouse pads placed in a row, so that you have a bigger, uniform space. I suddenly have a few ideas. But I understand that those amp feet isolators work well as they let the cab resonate more as there is less surface dampening.

I just took a scissors, cut a couple of mouse pads in half, and stuck two pads under both feet on the left side, and two pads under the feet on the right . I figured double pads might work out better. I haven't had any issues, but of course my amps and cabs are different from yours. It's probably going to take a bit of experimentation and fiddling.

But the fiddling is half the fun, right? (joking)

I'm one of those folks who runs two separate amps, each into its own cab for "wet-dry" setups. So my choices are simpler. Others here will have better answers to how to connect multiple cabs to a single amp!

 

[Goran Lorencin]

Although if I go to my 4x12, it's 16 out > 16 mono in.

Do you have 32 Ohm speakers in two pairs in your cab?

 

[Bill SAS 513]

I actually cut up one of those blue yoga matts...(Sorry, Shawn... )
A few layers of that (with a sheet of 3/4" plywood) has to absorb at least some of the vibrations from the speakers to the heads.
Note: This is for my bass heads, and speaker cabs...
For guitar, I have a shelf where my heads don't sit on the single 2 X 12" cab I use.

 

[alantig]

Do you have 32 Ohm speakers in two pairs in your cab?

Not sure - it's an Orange PPC412. Closed back, so I've never seen the speakers. From what I can see on their site, it just says it's 16 ohms mono, with the capability to daisy chain it to another cab for an 8 ohm load.

 

[Deleted member 5962]

Do you have 32 Ohm speakers in two pairs in your cab?

huh?

 

[László]

I actually cut up one of those blue yoga matts...(Sorry, Shawn... )
A few layers of that (with a sheet of 3/4" plywood) has to absorb at least some of the vibrations from the speakers to the heads.
Note: This is for my bass heads, and speaker cabs...
For guitar, I have a shelf where my heads don't sit on the single 2 X 12" cab I use.

That's a great idea.