I was looking on GuitarFetish out of curiosity and I came across a pre-amp booster called the Onboard Multi-Distortion Circuit. I was wondering if anyone has had any experience with it, or any GuitarFetish pre-amp booster, and if it does what it says it does (i.e. has 4 distortion sounds including AC-30, Overdrive Twin, Marshall Lead, and Mega Overdrive). Also, would something like this be digital?
I thought newey said he had one or other of their boosters. I'd love to know how this sounds. It's just so fricking cheap! I've been thinking about trying to build a multichannel amp simulator, and this might be an extremely easy way to accomplish it...
I'm pretty sure it's all analog. There's some pretty tried and true circuits out there for emulating amplifiers.
They try to replicate various amps and tube circuits using field effect transistors. I built the 'Fetzer valve' into a guitar as a nice warm booster stage. Ive also built several stompboxes on similar principles, though not to their actual designs.
JFETs are ideal as preamp stages because they respond to gain and overdrive is quite a valve-like way - they can also be designed to run on low current. Three or four stages can be arranged to draw less than 0.5mA, so batterys last very well.