Buzz from Fender Rumble 100 / 115 bass amp (V1)

[Craig Williams]

Got this amp second hand today (carpet covered disco light version ) and while the amp seems to be working fine there is a pretty distinctive buzz when you plug a lead in, even before plugging a guitar in. When I do plug the Bass in it buzzes just the same. So what I am saying it's not from the guitar, and I have tried several leads all doing the same thing. Without a lead in the amp turned on it is silent. It is a buzz, as opposed to a tube amp type hum (yes I know it's SS)

One thing I have noticed is if I back the mids off on the equaliser a bit and turn the tone down full bass the buzz almost goes away.

The amp only has a 2 pin plug, no ground so thats not the issue. I am in Thailand and the power here can be notoriously dirty. My other amps get a buzz sometimes but not quite as bad as this. Anyone have any ideas?

 

[agedhorse]

If the amp is quiet with no cable plugged into the amp, it's not a power problem or an amp problem. What you are describing is where noise is getting in through the input as signal.

Typical causes are using a speaker cable as an instrument cable or using a poor quality instrument cable. If the guitar is not properly "grounded" or shielded, this can also contribute. It is normal for an unterminated instrument cable to be noisy though, it should get better when the instrument is plugged in.

It's also possible that there is enough EMI present in the environment that it's overwhelming any shielding in the cable and guitar so try the amp in a different location to see if it improves.

 

[Craig Williams]

If the amp is quiet with no cable plugged into the amp, it's not a power problem or an amp problem. What you are describing is where noise is getting in through the input as signal.

Typical causes are using a speaker cable as an instrument cable or using a poor quality instrument cable. If the guitar is not properly "grounded" or shielded, this can also contribute. It is normal for an unterminated instrument cable to be noisy though, it should get better when the instrument is plugged in.

It's also possible that there is enough EMI present in the environment that it's overwhelming any shielding in the cable and guitar so try the amp in a different location to see if it improves.

Seems to be sorted now. Looks like I was just too close to the amp before. In a small space, probably 4 or 5 foot away. I move back another 2 foot and noise gone. Thanks everyone for the help