Module Description Controls & Ins/Outs
hh88w.JPG (23739 bytes) HH88 Drum Module

The HH88 is an accurate replica of the TR808 hihat drum sound. The module is entirely discrete analogue circuitry, based as closely as possible on the original. The HH88 has addition of a Tune control for both, and Decay on the closed hihat sound. The two hihat sounds are made up of six filtered square wave oscillators, fed through separate VCA's controlled by envelopes (a VCA and EG per hihat sounds).

The HH88 can produce more than just hihat drum sounds. The HH88 has the addition of a decay control for the closed hihat, and the decay time for the open hihat has been extended. This enables TR808 cymbal style sounds to be produced.

Inputs:
Tune CV 0 to -12V
CH Accent socket 0-12V
CH Trigger socket 5-12V
OH Accent socket 0-12V
OH Trigger socket 5-12V
OH Decay CV 0-12V

Outputs:
3.5mm CH/Mix audio out
3.5mm OH audio out

Power:
+/-12V, 5V

Controls:
Tune, CH Decay, CH Level, OH Decay, OH Level

Indicators:
none
Size:
10HP

Use

The trigger input has a range of about 5 to 12V. A trigger pulse of around 1mS is recommended, although the gate output of a synth can be used. A larger trigger pulse will increase the level of the sound (accent the notes). When the accent socket is used, the trigger input socket only triggers the sound and the level of the sound is controlled by the voltage of the CV at the accent socket. The accent voltage can be from another trigger pulse generator, or from an LFO or Envelope. When using for example an LFO, you can have the level changing with the LFO sweep.

When both hihat sounds receive a trigger at the same time, a muted hihat sound is produced.

The Tune control changes the tuning of one of the six square wave oscillators. This allows new timbres to be produces. The Tune CV socket allows some control over this feature. It's range is 0 to -12 V.

Both sounds will come out of the CH/Mix output, unless a jack is placed in OH output socket, in which case each sound comes out of its respective socket.

When using either the Tune or Decay CV inputs, turn their respective controls full anti-clockwise.

Controls

Tune Sets tuning of 1 of the 6 oscillators that makes up the sounds.

CH Decay Sets the closed hihat decay time.

CH Level Sets closed hihat output level.

OH Decay Sets the open hihat decay time.

OH Level Sets open hihat output level.