Simple CabSim

Schematic

This is a nice and simple cabinet simulator designed by Lart. You can find more information about it on diysompboxes.com. What I really like about this cirtcuit is that it only does one thing and it does it well, without external controls this is a perfect solution to drop in a preamp stompbox or a D.I. box.

Alternative transistors

I have simulated it in LTSpice with pairs of PNP / NPN from different series. In the next plot you can see the frequency response using the specified BC560C/BC550C pair, 2N5087/2N5088 and 2N3906/2N3904.

As you can see, 2N508X come pretty close to BC5X0C, with 2N390X having a smoother curve.

Veroboard layout

I have drawn a vero layout to build it, its a bit croweded but smaller than I was expecting. I recommend using a multilayer ceramic for the 1uF capacitor.

My build

This is my build, I used 470pF and 220pF in parallel beacuse I didn't have any 680pF, and 2N390X pair being the only pair I have at hand.

This sounds really well with a 1W PUNCH amp, I'll post a video when I have it boxed up.

11/09/2014 Update: I have uploaded my LTSpice file for anyone who want to try it. Right click on the link and choose "Save as": SimpleCabSim_yeraym_vulcanofx.asc

Mxr Headphone Amp + ROG Condor Cab Sim

This is  my silence practice rig, it is an mxr heaphone amp (layout by mirosol) and a runoffgroove Condor Cab Sim in one 1590bb box. Each one has its own input and output jacks, but I used switched jacks and the output of the cab sim is internally connected to the input of the headphone amp when neither of them has a cable connected. This is not one of my best looking builds but its the most used one.

I did my own layout for the Condor, and included a switch to select between condor and marshall simulator. I used a bicolor led.