User manual

New and Changed Controls

The Overdrive pot controls the level of Oscillator signal fed to the filter. This varies the

amount of oscillator signal between none, through normal to heavy overdrive (66.6 times

normal) which causes the filter to operate under duress. There is no danger to the filter, but

the sound is big.

The Slide Time pot. Normally the slide time is 60 ms (milliseconds). In the Devil Fish, the

Slide Time pot varies the time from 60 to 360 ms, when running from the internal

sequencer. When running from an external CV, the time is between 2 and 300 ms.

The Soft Attack pot varies the attack time of non-accented notes between 0.3 ms and 30 ms.

In the TB-303 there was a (typical) 4 ms delay and then a 3 ms attack time.

The Decay pot – which used to control the Main Envelope Generator (MEG) – now controls

the Volume Envelope Generator (VEG). The TB-303’s VEG decay was fixed at ~ 3 to 4

seconds. The first half of the pot’s range varies the decay between 16 ms and 3 seconds. The

second half retains the long decay but makes the final volume vary between silence and full

volume – so indefinitely long notes can be produced.

On non-accented notes, the TB-303’s Main Envelope Generator (MEG) had a decay time

between 200 ms and 2 seconds – as controlled by the Decay pot. On accented notes, the

decay time was fixed to 200 ms. In the Devil Fish, there are two new pots for MEG decay –

Normal Decay and Accent Decay. Both have a range between 30 ms and 3 seconds. The

MEG drives the filter via the Env Mod pot. On accented notes the MEG also drives the filter

frequency via the Accent pot which drives the Accent Sweep Circuit. The output of the

Accent Sweep Circuit adds to the VCA volume, in addition to the current produced by the

Main Envelope Generator. The Accent Sweep circuit, together with the Resonance Pot

turned to the right, gives the distinctive acidee “wow” upwards filter sweep at the start of

accented notes. Now that the time of the MEG can be manually controlled for accented

notes, the “wow” or “wapp” time can be made shorter or longer.

In addition, this sweep circuit can be disabled with the Accent Sweep Switch. Disabling it

stops the filter and VCA being affected by the MEG’s output via the Accent pot. However,

accents will still be audible due to the different time of the Env Mod filter sweep if the

Accent Decay time is different from the Normal Decay time and the Env Mod pot is turned

up.

There is a pushbutton switch to activate Accent manually at any time.

In the standard TB-303, the Resonance pot drives a special circuit – the Accent Sweep

Circuit – to pulse the filter frequency and add to the volume on accented notes. When the

Resonance pot is anti-clockwise, this is basically a direct pulse proportional to the setting of

Accent pot, and is derived from the MEG. When the Resonance pot is clockwise, this pulse

goes through a “lag” circuit which causes the filter to sweep up at the start of the note. This

gives the distinctive TB-303 resonant “wapp” sound. In the version 2.0 and later Devil Fish,

three modes are available, selected by the Sweep Speed switch. (Several of the 1.x Devil

Fishes were retrofitted with this switch.)

The Sweep Speed only operates on accented notes, depending on the setting of the Accent

pot and the time of the MEG as controlled by the Accent Decay pot. The differences

between the modes are most pronounced with a series of accents on short consecutive notes.

(Turn the filter into self resonance and turn down the Env Mod pot to hear the differences.)