Ace Tone Rhythm Ace with MIDI

YouTube via rolandsh1000

"This is a short demo of an Ace Tone Rhythm Ace Drum Machine to which I added MIDI trigger capability.

It's being triggered by an Oberheim DX'a' (the 'a' was the last DX model made by Oberheim and featured stock MIDI), running a few simple patterns.

The Rhythm Ace has about 9-10 drum sounds, most of them are made using resonant transistor oscillator circuits - all the transistors are Germanium - with inductors. There are no IC's anywhere within the Rhythm Ace (well, now there is with the MIDI board). Ace Tone ultimately became Roland, and while the classic TR-808 typically uses a different type of drum oscillator circuit, it's interesting to me that the Rhythm Ace seems to have a Roland quality to the sound.

The MIDI board is made by Highly Liquid and is actually intended for use in the Atari 2600. I added some interface circuitry that inverts and creates brief decaying-exponential triggers from the pulses of the Highly Liquid board.

One limitation here is that the Ace Tone COULD respond dynamically to the triggers, as the sound varies depending upon the shape and size of the trigger pulse. I didn't optimize for that, and that's pretty much why you don't here any open hats or low congas. And you CAN get the bass to boom a la 808 by tweaking a trimpot in the Rhythm Ace, but I held it back a bit here.

I do apologize for the lack of bass here - it's due to the lousy mic on my video camera. Someday I'll get my act together and record these videos with a mixed line-in to the camera."