Whats causing this sound from my amp...(warning, non-Alembic content)

[glocke]

at the one minute 20 second mark there is a distorted sound coming from my amp...and than it happens at various other times as well.


I can't figure out if its a blow driver, im overdriving the preamp stage of the amp (Demeter Bass 400), or if its fret buzz as was suggested elsewhere (bass is setup pretty good, and during normal playing and even when I dig in at home I never hear fret buzz).

[keith_h]

It sounds like fret buzz to me but I admit I don't have the best speakers and can't see how you are sticking the string. Might be from a raised or loose fret being effected by changes in humidity.

[gtrguy]

Check your 12AX7 first, as any tube is often the first thing to go bad.

[mario_farufyno]

I can imagine several causes...

If it was preamp overload one should expect it to happen to all notes played as hard as that one. If it just happens in a single neck position it surely can be fret, but if it happens on a determined note despite neck position (like all those Es at 12th, 7th and 2nd frets), it probably relates to resonance and it could be caused by blown speaker or simply something ringing with this particular frequency like the cabinet grile or any object loose on stage free to vibrate. And, lets not forget, it could be someting in camera mic if no one heard it at the moment and the noise just shows at video (a mic can vibrate too).

[mario_farufyno]

Blown speaker use to sound distorted all time regardless which note or even how hard you've played. It can distort more or less, but we should expect it to be more even. I would bet to be some resonating object, like the amp's head being shaken over the cabinet or some grile screw a little loose. It can be an object far away from bass amp either since lows needs lots of power to match guitars loudness and have real large wavelenghts (reach longer distances). I don't know if a loose grile would be loud enough to be heard along with the entire band playing in a live context, but if you were unlucky enough to have a mic near it will.

In studio this is something we look for. It is funny how a mic can reveal problems you weren't aware at regular hearing distances.

I would try to replicate to see if it just happened at that stage to find out if it is really your gear's fault. Doesn't seem fret to me.

[jwright9]

Make sure all the screws on your amp are tight. A loose connection somewhere could cause buzzing when certain frequencies are hit at the right decibel levels.

I had a similar issue about a year ago and it was driving me nuts. Finally figured out that one of the screws had come loose on the speaker and certain frequencies were causing it to buzz. (one of the screws that holds the speaker to the cabinet)

For me it was middle E, every time I hit E on my A string 7th fret or on D string 2nd fret I would get the buzzing. Same note one different strings.