How To Rewire Roland DS90 Speakers (For Humanities Students)

After so many years of literary analysis and myriad other right-brained ventures, I've become quite sluggish in mathematical type analyses. So, when I accidentally blew the internal amplifiers on my Roland DS90 desktop monitors, it took six years of procrastination before I finally opened them up and converted them to passive speakers.

Wiring in series and parallel I could understand, but when it got into the heady world of impedance and frequency crossovers, my brain started to swirl. I'll try to give the condensed version of how I figured it all out.

First, these monitors have two speakers, one standard for all frequencies, and one tweeter for only high frequencies.

A "crossover" is a speaker wired in parallel that has it's frequency limited by wiring in one or more capacitors.

I found out the "crossover frequency" of my speakers, then checked out this site to calculate the proper capacitance

Then it was a matter of rummaging through my junked circuit boards to find the right capacitors. That same site I linked to has a nifty little calculator that tells you how many farad you get when wiring the capacitors in different series or parallel combinations.

Now for the build pics:


The monitors with their butts ripped off.














The capacitors wired in: 2 10 microfarad caps in series, and 1 2.2 microfarad cap in parallel = 7.2 microfarad















Hacking the input: After I went all Om Nom Nom on the preamp circuit board...











I used the existing RCA input jack, and kept the rest of the amplifier guts intact, guessing that their physical presence has an effect on the overall sound of the monitors.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.