stange amp interaction with guitar volume knob

[Chickenwings]

So, when i roll back the guitar volume a little, the volume drops as expected, but the noise floor on the amp rises. Loud humming. Then if i roll the volume all the way back to zero, the humming stops.
It only happens with one amp, but the same phenomenon occurs with two guitars. These guitars are also fine with my other amps. So we can discount an issue with the axes.
Anyone else come across this?
What is the cause?

 

[Chickenwings]

Re: stange amp interaction with guitar volume knob

Hmm...turns out if i swap leads all is ok....
but if i use the same lead with a different amp there is no problem.
Weird.

 

[AlexR]

Re: stange amp interaction with guitar volume knob

I know sometimes when I had 50's wiring on strats for a time the noise floor would do the same. I wonder if there is a possible ground interaction in there which just doesn't play well.

 

[ehdwuld]

Re: stange amp interaction with guitar volume knob

by swapping leads
do you mean changing the way you have the guitar cable plugged in?
just reversing it?

I have a cable that does this

loose connection in one end of the jack

 

[Chickenwings]

Re: stange amp interaction with guitar volume knob

thats probably what it is. At least i know its not a problem with the amp.
Thanks!