Tone Report Weekly Issue 114 - Page 44

Changing a Dyna Comp to a Ross Compressor Players such as Trey Anastasio sing the praises of the Ross Compressor quite often, as it was among the first—and thusly, classic—pedal compressors. Mr. Anastasio places his Ross after two Tube Screamers for his distinctive tone. In fact, most boutique manufacturers of compressor pedals jump at the chance to drop the Ross name when describing the origins of their offerings. When browsing compressor pedals, the coloring is no accident—most grey ones are based on this age-old design. However, one red pedal is also based on the Ross: The MXR Dyna Comp. And modding it to Ross specs is a relatively simple job. 44 TONE TALK // What you’ll need: 2x 470k resistors, 2x 220k resistors, 1x 10k resistor, 3x 1uF electrolytic capacitors, soldering iron, desoldering pump/braid, screwdriver, utility knife The fix: The name of the game here is desoldering two different resistors from the board and replacing them with a hand-wound triangle of parts. It’s a bit of a hack job, but bear with me. The Dyna Comp board contains many 1m resistors, all of which go to ground except one. The remaining resistor connects to the center pin (base) of a transistor (Q1) on one end, and a voltage source on the other. Also, there is one 470k resistor on the entire board, connected on one end to voltage, and on the other, to the center leg of a trimpot. Both these resistors need to be desoldered. When you do so, make sure to clear the solder from the holes on the board very well. We’re going to make two quick RC networks to solder in their places using both 470k and one capacitor, and both 220k with the other capacitor. (see diagram below). There’s also a trace we need to cut and a resistor we need to install. Deep breaths. 5 Minimal Mods for Budding Builders