I'm thinking about getting a Keeley katana for a nice clean boost to drive the front of my dirty marshall. Anybody here have one or use one and what's your opinion of it?
I had one, it sounds pretty good, it's a double fet circuit in cascade, it fattens the sound a bit, very useful to drive a hard clipping OD pedal input or the input of the amp, used alone the effect is less evident but the sound is pleasing, a little more harmonically rich.
(I prefer for boost a light OD than a perfectly clean boost however)
With single coils i like a light OD from a tubescreamer (ST-9 clone) with the mid push on 720 Hz, with humbuckers i prefer a treble booster (in my case a Catalinbread Naga Viper clone) to demud the overdriven sounds.