Looking for some advice... The scenario: I have an '07 Thumb 5 NT with stock electronics including a preamp that at least one guitar tech assures me is toast. (It's making weird hissing/swooshing sounds reminiscent of the "ocean" sound you get when you stick your ear up to a seashell.). I thought the problem was with the volume pot (on the stacked volume-pot/blend-pot/bypass-push-pull control) based on the fact that the noise was consistently baddest in the middle of the volume pot's range, and would only go away completely when the bypass switch was pulled and the volume pot was turned completely down, but the tech assures me that "bad pots don't sound like that" and it's the sound of "a bad preamp." (I have a replacement pot from warwick, but no burning desire to mess with the 15-or-so solder points that hold it to the board.) Question 1: Any suggestions (or practical experience) for confirming (or refuting, or refining) the "bad preamp" diagnosis before I buy a new preamp? I've got a new set of leads for my multimeter arriving tomorrrow (don't ask) , and I'm *hoping* that I can think my way through the signal chain and observed behavior well enough to do at least *some* degree of fault isolation. (Best case scenario, I'm able to isolate the problem to some ten-cent diode and rip it out and solder a new one in place.) Question 2: Other than replacing with a stock Warwick replacement unit ($240 if I order from Warwick; or $240 *and* a six-month wait if I order from the US distributor!), does anyone know of an aftermarket onboard preamp that would work with the Thumb's stock pot/knob/controls? Question 3: Does anyone know if Warwick will let you buy one of their new-fangled custom-shop preamps? (With the rechargable lithium battery and micro-USB charging port?) Question 4: I'm slightly in-lust with the Aguilar OBP-3 (SK/PP), which comes with its own tone controls, and (I think) would just leave me needing to swap out my stock volume/pan/push/pull with a stacked volume/volume control... but since I'm already departing from stock functionality anyway, does anyone know if it's possible to run an OBP-3 with three knobs as: (1) stacked volume/blend pots, push-pull bypass; (2) stacked mid-cut/boost and mid-sweep pots; and (3) stacked treble/bass pots? (I didn't see anything indicating that's a supported set of parameters, but I got the impression that some supported options or combinations thereof aren't all that well documented. Any assistance *greatly* appreciated!