Ghost in the amp....

[jonnythenotes]

Can the vibration of your cab handling and flexing to lower notes...Bottom E and upto an open A string, induce mega distortion in an amp that is sitting on top of this cab, as if it is making a dry joint rattle....... It's a really aggressive distortion that doesn't build or fade... Just 'on' as a signal hits the amp, and then instantly gone as the signal from the guitar weakens after the initial striking of the string. Te amp in question is an Epifani PS 600, which is an early D class circuitry system. Also, being very scarce, is there anyone out there who is capable of opening it up and isolating the problem, and then fixing it......

[icastle]

First thing I'd do is change the battery in my bass (if it's an active).
Next up would be to beg\borrow another amp and see if that does the same thing.

Once those are out of the way then you'll have a much clearer idea of where the problem is.

[planer]

Play a note that makes the noise, then lift your amp up off the cab.

[rogerstodge]

That happened to me once on tour, i had to put the amp on the floor because of cab vibration (2x15), got it home stripped it down and was lucky enough to see the dry solder joint, i dripped some solder on it and presto.. It was an acoustic 360 head.

[ambient]

Sounds to me like the battery in your bass.

[jonnythenotes]

Does it whether passive or active... Tried everything, leads, batteries, swap guitars, swap cabs and speaker leads. This can only be the amp.. Completely random when it does it, could be as soon as you switch it on, or an hour after using it at a gig... Still think it might be a dry joint, but need a tech guy to check it out as its a D class amp.