User manual

1 - Overall description

The 32 Bank Memory system provides 32 times the normal memory of the TB-303 (or TR-

606 or TR-808). This can be used for storing more patterns and tracks, but its most

important capability is that the Internal Sequencer, while playing a pattern, can be switched

instantly to another memory bank, by the manual manipulation of five toggleswitches and a

pushbutton switch. Since the Internal Sequencer reads note information from memory in the

microseconds before it plays each note, this means that manual operation of these switches

can cause the Internal Sequencer to play notes from different patterns, in the middle of a

pattern. This is much more musically fruitful than the unmodified instrument’s existing

capability, in Pattern Play mode, of switching from one pattern to another, with the new

pattern starting when the current pattern ends.

From February 2014, I am able to install a variant of this 32 Bank system which enables

Dynamic Bank/Channel Switching. This involves the potential inversion of address bits 3

and 2 (as described below) by detector circuits, with approximately +1.15 volt thresholds,

working from two Audio or CV input signals which arrive in two 3.5mm sockets on the

left side of the machine. If each of these detector circuits is activated, the associated LED is

turned on and the address bit which is normally produced by the associated switch is

inverted.

For the TR-606 and TR-808 the same applies, but for the TR-808 I can install four input

sockets, detector circuits, LEDs and address inversion circuits, which will potentially invert

address bits 3, 2, 1 and 0. For simplicity, most of the following explanation assumes a two-

channel system for the TB-303, TR-606 or TR-808, applying to bits 3 and 2.

These input sockets, detector circuits, LEDs and address bit inversion circuits are described

fully in Section 5.

This manual is primarily for the TB-303 the Devil Fish mods, with notes about the TR-606

and TR-808 in brackets. (The 32 Bank Memory system, with or without Dynamic Bank

Switching, is independent of the Devil Fish mods, so I could install them in a TB-303

without the Devil Fish mods. So far, everyone who wanted this system wanted it installed

with the Devil Fish mods.)

The 32 Bank Memory system provides 32 times the normal memory of the TB-303, TR-606

or TR-808 – with the ability to switch from one bank to another while a pattern is playing by

operating toggleswitches and/or a pushbutton switch. This enables changes to the notes

played by the Internal Sequencer on a note-by-note basis, in the middle of a pattern, in

contrast to the usual arrangement by which the Internal Sequencer finishes one pattern

before starting the next.

In the discussion which follows, the term "bank" refers to the total memory of a TB-303:

•

Four Pattern Groups (I, II, III, IV) each of 16 patterns, 1A - 8A, 1B - 8B. This is a

total of 64 patterns.

•

7 Tracks (songs) numbered 1 to 7. (Actually 7 starting points in the long track

memory.)

(In the TR-606, a "bank" of memory consists of 32 patterns of up to 16 beats – and 8 tracks.

The TR-808 has 16 patterns and 12 tracks. Each TR-808 pattern has an A and a B section,

with each section being initially 16 beats long in its first part and 0 beats long in its second

part, with the total length of the two parts being 1 to 32 beats.)