I hope someone will (i) see this and (ii) be kind enough to offer an opinion and / or advice.
My Rumble 100 is fine with one possible exception [I can't be sure it's the amp because I am a complete know-nothing when it comes to the technical points raised in this thread]. Anyway, I've had a series of Fender P and PJ basses that all have or had a "muffling" problem on the D string from as low as F up to C. An American-made Geddy Lee I sent back to
Sweetwater had the same problem. I concluded it had to be a Fender problem but I'm having a similar [but not as bad] problem with the used Marleaux Votan I've had for about 10 days.
I've EQ'ed the amp every which way and done the same kind of experimenting with the active preamp in the bass. I can't make the problem go away [it's actually G-C, most noticeable at A&B, on the Votan]. The guitar really shines through the amp in every other way, e.g. great clear low growl on the E string, A string is fine all the way up and the G string is as bright and articulate was I want it to be.
The amp is the common denominator here. Any thoughts? Thanks.