Vintage Drumfire DF-500

via this auction
"(Taken from an old advertisement)
When you want to heat up the beat with electronics, get Drumfire. It's the only add-on mixer/synthesizer for drums. Drumfire works with any drum set, even practice pads. Its five piezoelectric transducers attach easily to your drum head or rim. Each tranducer lets you set a separate, chngeable electronic drum sound. A kick sound with punch, hand claps, synth sounds, and more. In fact, Drumfire gives you an almost limitless variety of synthesized drum voices. All for about one third the cost of an electronic drum set!

Drumfire gives you the best of both worlds- advanced electronics that enhance your acoustic drum sound. When you like it hot, play with fire. DRUMFIRE.

The Drumfire mixer/synthesizer has 5 separate channels to let you pre-set 5 different electric drum voices....synth sounds, hand claps, super kick, gunfire and more.

Each channel has 8 controls to let you find just the sound you want:
SENSITIVITY: controls pickup sensitivity
OSCILLATOR DECAY: controls decay time of oscillator sound
NOISE DECAY: controls decay time of the noise sound
SWEEP: alters oscillator frequency.
PITCH: changes oscillator pitch
BALANCE: controls balance between oscillator and noise level
VOLUME: controls output
PAN: a right or left balance control, also allows dual output on rigth and left jacks

Each channel has an input jack for the pickup, and an output jack for individual outputs to a P.A., mixer or amp. There's also a master volume level control, a left channel and a right channel."