I recently replaced the Keen (McKeen) preamp in a bass with Nordstrand dual coils for a Nordstrand 3-band. The Nordstrand pre sounds great: It has a fidelity that the Keen didn't and it's opened up the top end beautifully, but compared to the Keen preamp, the treble band is basically unusable for anything but cut - with the slightest high end boost, it's noisy like a soloed single coil and it gets worse the higher I boost. At 50% boost, it would be completely unusable in a live setting. This experience is unfortunately repeatable, irrespective of audio leads, amps, speaker cabinets, power outlets, venues, days of the week, etc. It's on rare occasion that I actually boost treble, but if slapping is called for, I use it this way. I imagined that a Nordy preamp would work with Nordy pickups nicely: Do I have a grounding issue? The noise only occurs when I'm not making contact with the strings. The control cavity is well shielded. For what it's worth, when I switch from parallel to series operation, the noise remains but the frequency of the noise is lower. Has anyone else experienced this? What about Nordstrand bass owners? Is this par for the course? Are they just noisy? Any ideas? Thanks!