good will audio generator

I briefly mentioned this piece of kit earlier:

A few months ago my mate Dangerous Dave gave me a frightening-looking piece of medical equipment about the size of a microwave oven. He said it was supposed to generate tones but when he’d plugged it in he blew all the fuses in his house (not sure how that works) so he thought I might like it.

“Tones?” I said. “Okay I’ll have a look.”

And I put it in the corner of the studio and there it sat, gathering smaller items onto its large flat surface.

A couple of weeks ago I finally had a proper look at it. I still don’t know exactly what it was and I forgot to take a photo before I dismantled it, but inside it there was indeed a sine wave / square wave generator, (pictured) with a range of 10Hz to 1000kHz (One Million Hz!)

Most of the rest of the microwave-sized case was filled with a big amplifier and some complex digital and analogue metering equipment. Some of it might still work (later) but something in there was badly shorted.

With a very small amount of tinkering and a couple of new components (switches, jacks and LEDs) I managed to get the noise-making part operating without the fuse-blowing part and it sounds like this (with echoes of course):

ACHTUNG!! TURN YOUR VOLUME DOWN NOW!!!

The first five buttons on the left determine the frequency range. The highest is 100,000 Hz to 1,000,000 Hz! (For non audio geeks: humans hear up to about 20,000 Hz on a good day.)

The last button switches between sine and square waveforms.

I took it out last weekend for a bit of a play at an outdoor dj thing I do at the market and it was a lot of fun. It now has a permanent place in my arsenal of audio weapons.