Rattling Noise

[tob]

Hi everyone,

I just finished building my first Express clone and while it does sound amazing there's a pronounced rattling noise (very much like a loose screw/washer) that gets amplified and whose intensity peaks when certain notes and chords are being played...so resonance seems to play a role.

Would anybody here here have an idea as to where to look for the source of this problem? Microphonic tubes maybe?

Cheers,
Tobias

[gearhead]

Do you have the amp on top of the speaker cabinet your using? If you can either take it off, or put some foam in-between the two, you should be able to tell if it's a mechanical vibration or not.

[Buschman]

Sounds like a tube to me. Click your fingernail on them or replace one at a time.

[Phil_S]

Sounds like a tube to me. Click your fingernail on them or replace one at a time.

Hard to know without hearing it, but I've had this with a rectifier tube (obviously not on the Express). I was amazed by this. On removing it, a light tap with the fleshy part of the finger, while holding it near my ear gave a very clear an audible acoustic duplication of the problem noise.

[Doug H]

Hi everyone,

I just finished building my first Express clone and while it does sound amazing there's a pronounced rattling noise (very much like a loose screw/washer) that gets amplified and whose intensity peaks when certain notes and chords are being played...so resonance seems to play a role.

Would anybody here here have an idea as to where to look for the source of this problem? Microphonic tubes maybe?

Cheers,
Tobias

Uh... Could it be... a "loose screw/washer"???

[tob]

Uh... Could it be... a "loose screw/washer"???

thanks for stating the obvious, Doug, but it's not a loose screw or washer. I did check on that, naturally.

[57goldtop]

You might want to check that your end bells screws are on tight.

I was getting some rattle which was caused by the resonance of the PT's hum.

[gearhead]

Let me repeat myself. Have you isolated the amp chassis from the cabinet to make sure it only occurs when there is physical and/or acoustic contact between the two?

The reason I'm asking is to make sure it's not something in the cabinet or the room itself. A new/different amp can bring out different resonances than with previous/other amps.

[Lonely Raven]

Let me repeat myself. Have you isolated the amp chassis from the cabinet to make sure it only occurs when there is physical and/or acoustic contact between the two?

The reason I'm asking is to make sure it's not something in the cabinet or the room itself. A new/different amp can bring out different resonances than with previous/other amps.

I get that all the time...sometimes I have to move amps that aren't even connected because something in the chassis starts vibrating!

I guess if I didn't have all my amps and cabs stacked 3 high I wouldn't have this problem..

[tob]

Let me repeat myself. Have you isolated the amp chassis from the cabinet to make sure it only occurs when there is physical and/or acoustic contact between the two?

The reason I'm asking is to make sure it's not something in the cabinet or the room itself. A new/different amp can bring out different resonances than with previous/other amps.

Yeah, the chassis does sit right on top of the cab so far. I'll see whether exchanging tubes and putting it in a proper wood case with rubber feet has any effect. If the problem prevails I'll record and upload an mp3.