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.
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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.
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