Ross Phaser

 Yes, Modulation Monday is back with the Ross Phaser. It's not for the feint of heart, but doesn't require any JFETs, matched or otherwise. Instead it uses OTAs with 3, LM13700N (one for the LFO, two for the audio path). Should fit nicely in a 125B with top mounted jacks. Schematic for reference.

Ross Compressor

Somehow I've not laid this classic out already, so here's the Ross Compressor. One of the most highly thought of (and therefore copied) compressors of all time. Should be an easy fit in a 1590B.

The Drivestortion Project

I really enjoyed making the Big Muff Project file a couple months ago and thought it would be fun to make a similar project based on the MXR Distortion +/DOD OD250 circuit (in an attempt to combine the 2 names I call this project the Drivestortion). This circuit was also cloned by other pedal manufacturers (apparently this was the Timmy of the 70s), so the project provides component values for a couple of these as well. Let's start with the schematic:

This is the basic circuit for several versions of the DOD OD250, the MXR Distortion +, the Ross Distortion, and the DeArmond Square Wave, just to name a few. The only difference between all these is differing component values (and sometimes not even that). The component names from the above schematic follow those in the layout drawing below.

For a full BOM for 6 different versions of this circuit, download the linked file below. In addition to the BOM, it contains scaled transfers for etching your own circuit board and a scaled drilling template for building the effect into a Hammond 1590B enclosure.

Effects Layouts' Drivestortion Project

Ross Distortion

The Ross Distortion is very similar to two other famous distortion boxes of the late 70s (MXR Distortion +, DOD 250). However, it uses one side of a 4558 dual opamp instead of the single opamp (741) found in the the other two, and a few other tweaks in component values. There are two versions of this circuit: the Tan version, which uses 2 germanium diodes for clipping (originals used 1N270s, but 1N60Ps or 1N34As should also work just fine), and the Black version, which uses 3 silicon diodes for asymmetrical clipping. I've drawn up 2 layouts for each version, both will fit in a 1590A. The only difference is improved power filtering and added polarity protection in the larger layouts. The yellow 1µ caps are tantalum.