Baja Reactor

This one was requested ages ago and I got halfway through laying it out, and then promptly forgot about it. It's a power amp/speaker cabinet simulator, emulating a SLO power amp and a couple different speaker cabinets based on the value used for CX (see schematic for values). This layout follows the Rev4 schematic from the thread here on FSB.

Hughes & Kettner Red Box Mk. II

Here's a nice utility box for home recording or even live application (if you've run into a sound guy who hates guitar amps 😠). It's a direct box but also a cab sim (4x12). It won't run off phantom power, so just power it with a 9v wall wart or a battery. Also, connected to the Speaker In pad should be another jack for "speaker through" (so you don't blow up your amp). Here's the schematic and original user manual for reference.

Update Nov. 15:
I removed the extra components for ground lift application as most reported it not working and they had better success with placing an on/off switch between XLR pin 1 and ground. YMMV

MultiCab Sim

Got a request for this one, designed by Daniel Schwartz. Seems to be a pretty versatile cabinet simulator. Might be handy to throw this in the same box as the Mini Amp from earlier this week. More info, schematic, etc here on DIYSB.

Also the next episode of the DIYLC tutorial is up on YouTube. Forgot to plug it in the post from Tuesday.

Simple CabSim

Came across this design in researching a different project and thought I'd draw it up. It uses 3 transistors and doesn't take up a lot of space, so you should be able to fit it in a 1590A or add it to another pedal. More info can be found here. Sounds like you can use pretty much any medium-high gain PNP/NPN pair for Q2-3 (2N5087/2N5088, BC560/BC550, etc).

Run Off Groove Condor Cab Sim

Part of the last request included a cab simulator to run the headphone amp through. The ROG Condor is a great cab sim and has a fairly low parts count. It uses a JFET amplifier at the input, boosting the signal to drive the following 3 filters (Bridged-T notch filter, High-pass filter, and Low-pass filter). Much more info on the circuit can be found here, as well as a few mods. J201 apparently sounds the best for Q1, but similar DSG pinout JFETs will also work. Any dual opamps can be used for the 2 ICs, so socket and try the usual candidates (TL072, JRC4558, etc).