Sync Lead

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This is an additional item we can supply with the a Devil Fish modified TB-303. It is not necessary for operation of the Devil Fish itself. The Sync Socket of a Devil Fish with or without MIDI In accepts Roland (DIN) Sync In exactly as an unmodified TB-303 does.
Devil Fishes with MIDI In also use the Sync Socket as their MIDI In socket.
The MIDI In system inside the Devil Fish receives MIDI Sync and drives the outside pins of the Sync Socket with the Run/Stop and Clock (24 pulses per quarter note) signals. Whatever signals are on these pins drive the TB-303's internal sequencer.

When nothing is plugged into the Sync Socket, these two outside pins are driven from the internal Run/Stop and Tempo Oscillator circuits, which are controlled by the Run/Stop button and the Tempo knob. When something is plugged into the socket, a double pole switch opens up and the outside pins are not driven from these internal circuits. However, when the MIDI In system receives MIDI Sync, it drives the outside pins - and therefore the TB-303's internal sequencer.

This is all that is required for ordinary Devil Fish synchronisation from MIDI. (The MIDI In system also enables the Devil Fish to be controlled by notes, and for Accent, Slide and Filter Frequency, as described in ../midi/ .)

The primary purpose of the Sync Lead is to enable all this to happen, while also using the Roland Sync signals (Run/Stop and Clock) which are generated by the MIDI In system to drive up to three external devices, each of which receives Roland Sync.

This means you can use the Devil Fish with MIDI In to start, run and stop up to three other devices, such as other TB-303s or Devil Fishes, TR-606s, TR-808s and TR-909s.

There are some other ways of using the Sync Lead:
As a four plug Sync Lead where one master device, of any type, drives up to three other slaves.
By only partially inserting the lead into a TB-303 (including a Devil Fish, with or without MIDI) you can connect the lead's pins to the socket without activating the switch which disconnects the internal Run/Stop and Tempo Clock signals from the socket. Therefore, by carefully inserting any one of the four plugs into the TB-303's Sync Socket, you can use its Tempo and Run/Stop controls to run the TB-303 and up to three slave devices at the same time.
DIY enthusiasts with good soldering skills can make their own:
Pins 4 and 5 (the inner pins, next to the middle pin) of the 5 pin DIN socket are connected to the same numbered pins of 5 pin DIN plug number 1.
Pins 1, 2 and 3 (outside and middle pins) of plug 1 are connected to the same number pins of plugs 2, 3, 4 etc.
There is no absolute limit on how many Sync In inputs can be driven from one Sync Out. Nor are there any restrictions on length or requirements for shielding - so a lead like this can be made as long as you like, with as many sockets for slaves as might be required.