Tag Archives: bs170

MOSFET baritone (guitar/bass) preamp

ok, so here’s a preamp design that i’m working on at the moment. it’s meant to be an amplifier simulator for my Gretsch Baritone G5265. i was impressed with the AMZ Booster using a single transistor and used a ’59 Bassman simulator (which uses J201s) as a loose guide. i’m looking to use it as a pre so i can run the baritone through an SS amp without it sounding dinky. it’s pretty experimental still, and i’ll most likely add a tone stack after Q2.

since the schematic post, i wanted to point out some potential sources of change. Q3 should be marked as a 2N4401 and not a 2N3904. both will probably work, but i originally used a 2N4401 (thinking it was a 2N2222A). i also did try out a 2N2222A but didn’t really like it as much (more beefy and less definition). i’ve been experimenting with MPF102s in the Q3 position today which definitely have a more pronounced high-end sparkle which is probably better suited for guitar. i’m going to try it out in the Q1 and Q2 positions as well just to see.

also, D1 is a 1N914. to be honest, i don’t hear any tonal effect with or without it. i saw a similar connection in the AMZ Booster schematic, but i’m not sure of it’s function yet.

MOSFET overdrive…

a forced contract job for Ryan of Falcon Scott. he’s been having some issues finding an overdrive suitable to his hollow-body guitar. i just got a lot of BS170s and thought this might do the trick. the distortion is pretty squared off on the oscilloscope and crunchy. the left pot is post volume while the right biases the BS170. overall, it sounds pretty good and that’s saying a lot coming from someone who isn’t much into “distortion” (personal bias does make a difference. hah).

a big thanks to Jack Orman at Musique.com for laying out the basis. i modified his schematic a bit to get the “best” results for my ear, but i couldn’t have done it without his work.