Modding the Frequency Analyzer

Adding something to a classic Electro-Harmonix Pedal

Mr. Nitefly, a prolific amazing local guitar player, and certified pedal freak, visited Beavis Labs a while ago to get his Electro-Harmonix Frequency Analyzer re-housed. It's a pretty big pedal:

But the PCB is quite a bit smaller than the case. After some measuring, I figured I could shoe-horn the beast into a Hammond 1590J enclosure. The idea was to also add true-bypass switching and a LED while I was under the hood.

I Can't Leave Well Enough Alone

The Frequency Analyzer has a Filter slide-switch on the back panel. Why not make that a stomp-switch also and add another LED? So I incorporated that into the design as well. Finally, I did a bit of research on the Frequency Analyzer and stumbled across a most excellent modding site: E xperimentalists Anonymous. Colin, how runs the place has an awesome CV mod where you can splice in a jack and use an external source for the CV signal. His ingenious solution incorporates a stereo 1/4" jack, so when nothing is plugged in, the circuit's built in CV generator is used.

Finally, adding true-bypass and an extra jack for the CV input meant that the existing "Direct" output jack would have to go. A quick consultation with Mr. Nitefly regarding specifics of the build and I ready to go.

How I did it

First, I disassembled the Frequency Analyzer and took lots of close-up pictures.I wanted to be sure that I knew have everything was wired in the stock configuration before I startedhacking the thing to death. Then I went about drawing out the simple wiring diagram. I needed to find the PCB input, output, voltage, and ground lines in order to figure out the true-bypass wiring.

After the plan was mapped out, I de-soldered the three pots from the board, trimmed back the long leads, and attached wire bundles to each of the pot lugs.

Next, it was on to the box: I measured the enclosure and drew template lines according to Mr. Nitefly's instructions. The idea was to have the three knobs equidistant across the top, the to LEDs in the middle, and then the two stomp-switches. Here's what the box looked like after marking:

Before committing to hole locations, I always like to double-check that the parts will actually fit in the space allotted. It's pretty easy to bolt jacks on to the edge of the enclosure and lay the other parts inside.  I've found its a great way to  visualize what I think I am going to do.

Next up, drilling. After pilot holes, I drilled all the appropriate holes.

Then I gave it a quick rough-sand and mounted the components to see if my plans were as brilliant as a I thought. It was a rare occasion indeed, as everything actually fit the first time, and I didn't have use any foul language.

In order to fit everything, I had to mount the PCB on the bottom cover. Used some stand-offs and it worked great.

Before putting the enclosure aside, I spent an hour or so wet-sanding it (150, 400, 800, 1500, and then 2000 grit sandpaper) and polishing it. Turned out very nice and shiny:

All Done





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