resonance issues

[57goldtop]

Hi,

I'm using my express clone through a 5150 4x12 slant cab and the box is
making a rattling/vibrating noise especially on the lower notes when the volume is turned up around half way. If I push on the back of the box while playing the horrible noise goes away.. what kind of insulation should I put inside the box ?

Cheers.

[Allynmey]

57, KF mentioned using a piece of foam when putting the amp on a 4x12 to cut down on vibration. A nice piece of 2-3" foam measuring 18X12" should do the trick.

Allynmey

[57goldtop]

I think the problem is with the cab itself and not the coupling between the amp and box, I have moved the amp away from the box and it still rattles. I will give this a try once my cab is built.

Thanks for the suggestion.

Cheers.

[nickt]

I think the problem is with the cab itself and not the coupling between the amp and box, I have moved the amp away from the box and it still rattles. I will give this a try once my cab is built.

Thanks for the suggestion.

Cheers.

Had this myself in my deluxe clone just recently. Luckily you didn't order "noo toobs" to fix the cabinet problem (like this numnuts!). Recall marshall quads have a central post connecting back to front, do you have some felt between the rear and the post or is the post screwed to the back? Either should fix your issue I think.

[57goldtop]

Apparently, the 5150 cab is almost identical to a Marshall 1960 cab so it should have a centre post, I was in there a few years ago to do some wiring and I vaguely recall the centre post but I don't remember seeing any insulation between the post and back.

It's approximately in that area where I push to make the resonance go away. Will get in there tonight to have a look.

Cheers.

[Allynmey]

Sorry, I thought it was the head that was rattling

[Lonely Raven]

Sorry, I thought it was the head that was rattling

Yeah, I thought that at first as well.

And +1 on the center post to the back of the 4X12 cab.

2 easy fixes/upgrades for many of the Marshall and Marshall clones.

#1 plywood back panel in place of particle board. Replace that junk that they put on there to save a few pennies with a nice solid plywood panel.

#2 thin sheet of dense foam stapled/glued onto the end of that center post to help couple the back panel with the front panel.

These two things will make for a more musical and tighter sounding cab, and are super easy to do.

[57goldtop]

Got in there last night and got rid of the rattle, there was no insulation between the centre post and back at all.. some foam did the trick and all I had to do was tape it around the post. Surprised that I never noticed this before and have had the cab for years!

On to making a new back panel..

Thanks for the suggestions.

[Lonely Raven]

I'm glad that worked out for ya!