Devil Fish mods for the Cyclone Analogic TT-303 Bass Bot
2019-02-25 Robin Whittle
On 28th November 2012 Cyclone Analogic http://www.cyclone-analogic.com
based in Hong Kong, released what is in many
respects a TB-303 replica, though they do not refer to it as such. "TT" stands for "21st Century Transistor Technology".
These went out of production around 2017/18 and are now known as the
Bass Bot Mk 1. The Mk 2 is smaller and not suitable for Devil
We plan to be able to provide a version of the Devil Fish mods for the
Bass Bot Mk 1 later in 2019. Below #mods
current thoughts on the planned mods. If you are interested in this, please let us know.
Please do not press down on the 6 small knobs (Tuning to Accent) when turning them.
If you do this, the pot's internal rotor is likely to cut into the
conductive tracks of the pot, rendering it non-functional and probably
unrepairable - and so in need of replacement. The forthcoming
Devil Fish mods will fix this problem so pressing down will not cause
this damage. Still, it is best not to press down while turning
The final section of this page contains information about the Bass Bot,
some of which may be of only historical interest. The tense of
the text remains unchanged. It was written while the Bass Bot Mk1
was initially released. This page was established
before Cyclone Analogic finalised their website.
Devil Fish mods for the TT-303
There is more work to do in order to finalise the modifications. I will update this page as
soon as I have
We have not yet
on pricing. Here is our current plan:
The capabilities will be the Devil Fish mods as
in the current User Manual ../Devil-Fish-Manual.pdf
with the following differences:
- There is no need for, or possibility of, the 32 Bank Memory
system. The TT-303 has plenty of memory. A major feature of
the 32 Bank Memory system is the ability to switch to other banks, and
therefore other patterns in those banks, in the middle of
patterns. As far as I know, there's no way with the current
TT-303 firmware of switching from one pattern to another in the middle
of a pattern - the current pattern will always play to completion
before the new one starts.
- We will install Omron sealed tact switches to replace the unsealed tact switches (one for each of the TT-303's buttons.)
- We plan to raise the switch panel a little so the buttons protrude a little more.
- It may be possible for us to improve the light transmission of
the LED windows, particularly when they are viewed from angles far from
perpendicular to the front panel.
- We will modify the 6 small pots to correct a
which affected the original TB-303 pots, and also the pots we are
now installing in TB-303 Devil Fishes when they need replacing.
The pots of the Bass Bot are similar. The downwards
movement of the shaft and rotor in the TT-303 pots is not limited by
the bottom end of the shaft itself. In the TT-303 pots, the
of the shaft is just a little too short, and the result is that if the
knob is turned at the same time the user presses down on the knob, this
will cause the outer part of the rotor inside the pot to rub on the
conductive tracks, which will eventually cut through one or more of the
pots, causing the pot to fail suddenly. In November 2015 I have
had one machine where this has occurred - the wiper connection of the
Cutoff pot was cut, and the filter frequency was too low for any sound
to be heard from the machine. An earlier version of the User
Manual (page 19) cautioned
against pressing down on the knobs, but there seems to be no such
caution in the version 2.0 manual. The 6 small pots have their
mounted a little higher than in the TB-303 and the pots are easy to
turn, which should reduce the tendency of people to press the knob
while turning it. Nonetheless, we want the Devil Fish modified
machines to be as reliable as possible, so we will be modifying these
pots so the problem cannot occur. This reduces the
side-to-side sloppiness of these pots. We use a lighter
silicone grease so the pots will be easier to turn.
- There's no need for, or possibility of, replacing the LEDs.
- We will also provide
MIDI Out via a 5 pin DIN to 3.5mm stereo adaptor lead and a 3.5mm
(TRS = tip-ring-sleeve AKA stereo) socket on the rear panel between the Sync socket and the Tuning
knob. This will mean that there is no need to use the TT-303's
supplied MIDI In and Out lead, since it is only needed for MIDI Out,
and MIDI In can be achieved by plugging the lead directly into the DIN
- As with Devil Fish 5.x, the headphone signal will be available from a 3.5mm
socket located above and between the Audio Out and old Headphone
- We plan to implement Controller 1 (Mod Wheel) on the current
channel, or perhaps some other controller number, as Filter Frequency
In, as in the TB-303 Devil Fish MIDI In or MIDI In and Out system,
where values sent on this controller number can drive the filter
frequency higher or lower than normal. I
have not yet decided if or how to alter the channel this is received
on. This will be done by a separate microcontroller and it may be
difficult or impossible for this to automatically determine the channel
the Bass Bot's microcontroller is receiving on.
- I will investigate the potential for sending and/or receiving Roland/DIN sync.
The 32 Bank memory system is not applicable to the Bass Bot.
This is applicable only to the TB-303 with its original
microcontroller, since this stored its pattern and track data in three
external memory chips. This system cannot be applied to the Bass
Bot's microcontroller, or any other such microcontroller (Quicksilver
303 and Sonic Potions) which store their patterns and tracks in on-chip
The MIDI In and MIDI In and Out systems are not really needed, since
the Bass Bot already has MIDI In and Out. However, the MIDI In
and Out system has special capabilities, including Dynamic Channel
Switching and CV to MIDI conversion. It may be possible for the MIDI In and Out system to be an option.
The Bass Bot cannot be placed in an AluCase, unless some kind of
light-pipe can be devised to get the light from the red-green-blue
surface mount LEDs on the switch panel to the holes in the
AluCase. There is no-doubt a way of achieving this, but I
currently have no plans to devise such an arrangement. The Bass
Bot cases are robust
and have a better paint finish than that of the original TB-303 case.
The following is retained in the hope that it will be of historical
interest. Much of this information is no longer current in 2019.
Some information on the Bass Bot
The information below may be of
interest, but it is not definitive. I prepared most of it in late
2012 and early 2013. Please see http://www.cyclone-analogic.com
for support and all definitive information from the manufacturer.
A new version of the firmware (2.0) was
released on 1 January 2005. I have not yet installed and
evaluated this. The URL for this is the same as for the first
update, which was to version 1.1:
On 2014-01-09 I have
a recent production Bass Bot but have not
yet had a chance to evaluate it in detail or to update this page,
so most of the following is written as if these new developments did
There's a page about the release at MatrixSynth:
and a brochure, of which a copy is here: TT-303 Bass Bot Brochure R1.1_ENG.pdf
From this brochure, the recommended retail prices are:
February 2013, on the Analogue Heaven mailing list (link below), quite
a few people reported purchasing Bass Bots and being generally
happy or very happy with them.
- UK: £449.00 + VAT
- EU: €549.00 + VAT
- USA: $699.99 + VAT
- Sweden: kr5995.
Here I note in red
potential problems in the machines which have shipped so far. All
this is to the best of my knowledge. Please let me know any
suggestions for improvements. Please also see discussion below of
a potential Volume Pot noise problem, for which there are several easy
The Bass Bot
everything a TB-303 does except:
- It does not receive Roland/DIN
(Many people do not use Sync In.
Implementing this would involve significant hardware and firmware
- Although the right-most button is labeled "Tap" as part of
replicating the design of the TB-303's front panel, there is no Tap
entry mode in the TT-303's sequencer.
(Many people would never use Tap mode, and I don't know if
this is something Cyclone Analogic plans to implement. This could
be implemented with a firmware change.)
- As noted below, the CV Output range is 0.333 volts (4 semitones) higher than that of the TB-303. In 2014 this was fixed in current production and with a firmware update, so the following is of purely historical relevance.
The TB-303 outputs 1.0 to 5.0 volts. The TT-303 outputs 1.333 to
5.333 volts. (This could
be fixed with a firmware change. Many people would not use the CV
Output, and most of those who do would have little or no difficulty
adjusting the manual tuning of the slave devices to bring them into
line with the desired tuning, provided the Bass Bot itself was tuned to
- When playing notes from MIDI In, the Bass Bot may be required to
start a note straight after the previous one has been turned off.
For instance the time between one note ending and the next starting may
be as little as 2msec (3 bytes for Note Off and 3 bytes for Note On) or
1.333 msec if MIDI is being sent with Running Status, requiring just
two bytes for Note Off and two bytes for Note On, for notes on the same
channel. This close timing between notes cannot occur with
the internal sequencer, since there is always a short gap (1/64th
quarter note, I think) between notes.
When playing closely spaced notes via MIDI In, there may be clicking noises. I
understand this has been largely resolved in current production, and
with the firmware update, but I have not yet investigated in detail. These are moderately loud and have sharp edges, so they are quite audible. Please see this waveform: click-fix/click-pink.jpg
. The magenta part of the waveform illustrates where the click occurs -
the VCA gain suddenly drops to zero at the start of a new note, which
in this case is while the decay tail of the previous note is still
going. The previous note probably ended around 15:228 and the new
note probably started around 15:230.
These clicks were reported to me on 2013-02-03 and the next day I
reproduced the problem on our machine, determined the cause and wrote
to Cyclone Analogic about it. I
devised a relatively simple two component change for the circuit which
solved the problem on our unit. I expect this would work well for
all Bass Bots. This is not solvable via firmware changes.
My suggested fix can be done without changing the PCB. Cyclone
Analogic have asked me not to post any modifications to their machines,
so I won't. However, for a technical description of the
problem, please see: click-fix/ .
This clicking problem was reported by Tim Webb of http://discchord.com . Tim writes extensively about iOS (Mac handheld) audio apps / soft-synths and provides professional beta-test services.
- There is a problem with Pattern Play mode in that when
playback switches to a new pattern, the first note played is the first
note (pitch and Accent, not Slide) of the previous pattern.
This is also true for the second pattern being an empty pattern - it
will repeatedly play the first note of the first pattern.
Switching from an empty pattern to another empty pattern results in the
second pattern being played correctly: with no notes. Switching
from an empty pattern to a pattern which starts with a note will
cause that first note not to be played.
The above description is for manually pressing buttons to select a
second pattern to play after the currently playing first pattern
ends. The same problem occurs if two or more patterns are chained
together by pressing the buttons for the lowest and highest numbered
patterns at the same time.
If pattern 3 and 5 is empty and pattern 4 has 16 1/16th notes, then if
I manually play pattern 5 and then select pattern 3 while it is
playing, pattern 3 will play correctly, without any notes, because the
previously played pattern 5 is empty. The same is true if pattern
5 started with a rest (program a note first and then convert it to a
(The problem described here is based on our observations of the
December 2012 model we received. The problem was reported by
"Computer Controlled" in the Analogue Heaven mailing list on 2013-02-07
in terms of the second pattern starting with the last note of the previous pattern.)
- All MIDI devices should receive the All Notes Off command from
MIDI In: Control Change 123 with a value of 0. This should turn
off all playing notes. However the Bass Bot does not do respond to this CC 123 All Notes Off message.
The synthesiser circuitry is functionally identical to that of a
TB-303 except (based on our experience with one unit sent to us in
- Maximum Env Mod is about 37% stronger.
- Accent Sweep via the Resonance Pot is about 33% stronger.
- The VCA is a BA6110, which is a modern, enhanced, version of the
original and now unobtainable BA662. The BA6110 has linearizing
diodes, which are not used, so it behaves much like a BA662. The
control current to the VCA is approximately doubled and the load
resistor for the VCA is approximately halved. The signal level is
about the same, but these changes reduce the VCA's background noise
- The CV Out range is 1.333 volts for lowest C to 5.333 volts for
the highest C in a Pattern's 3 octave range, when the Pattern is
transposed up 1 octave. In the TB-303, this 4 octave range is 1.0
to 5.0 volts. There is some evidence that two machines may have had their internal 5.333 volt reference
adjusted a little too high, so their CV output is slightly greater than
1 volt per octave. See my Analogue Heaven discussion of
this (link "I am replying to:").
- The exact response curve of the Resonance Pot is a "log" curve at
both the anti-clockwise and the clockwise ends. This is the same
as with the replacement Resonance pots we have been installing in the
Devil Fish for several years. The TB-303's Resonance pot has a
"log" (AKA "audio taper") response curve. This difference only
affects what knob position produces a given sound, not the range of
sounds which are available.
There may be a slightly higher filter resonance. Here is a note in green
reproduced with permission, from Modernpop writing to the Analogue
Heaven mailing list (see links below) on 2013-01-30, with my response
As a Bassbot user, bought after AH tipoff, this technical breakdown sort of goes along with my thoughts on its comparison with the TB-303.
It is so so much closer than any clone I've heard or used before, hardware or software, with a few things that seem almost there: e.g. turn the accent full and it seems to jump out more than it "should" in the sequence, turn it back a little and it's fine.
I feel the Resonance is a little OTT from 303s I've used, turn it back a little and it's great. Thoughts and feelings. I don't want to buy a TB-303 anymore if that's of any interest. Thanks Robin for the info.
This accords with something I hadn't mentioned - a hand-soldered resistor which controls the resonance gain when the Resonance pot is fully clockwise. I suspect that this resistor value, which was an unusual value - 11.2k - was chosen to tweak the feedback level to just under that required for self-oscillation. The exact value required to do this would depend on the exact values of several other components - and these values could vary somewhat with normal tolerances. If self-oscillation occurred, it would be heard if the waveform switch was in mid-gear.
I think these changes are all judicious - making the machine a little
more lively than a TB-303.
These observations are from one Bass Bot we received in December 2012.
This is an attractive, well-designed and well-made
instrument with the following key features:
- Exactly the same size and shape as a TB-303. Almost the same appearance, with similar or identical typefaces.
- The LEDs do not protrude from the front panel. In place of
the aluminium switch plate is a robust polycarbonate faceplate with
diffused windows for the LED light. All LEDs are tri-colour-
Red-Green-Blue, and the machine can display a complete range of colors
on each LED individually.
- Transmits and receives MIDI for Notes, with Accent (velocity) and Slide (two or more tied notes).
- MIDI dump and save of memory contents. This relies on some software for PCs and Macs which is yet to be released.
- Non-volatile memory - does not require batteries.
- Far greater Pattern storage 7 x 4 = 8 = 224 patterns.
- New and superior Pattern write and edit capabilities with
copy and paste. A number of TT-303 users have told me they think
the sequencer functions are greatly improved over those of the TB-303,
although as noted above there is no Tap entry mode.
can contain 64 notes, such as by copying up to four 16 note patterns
into one. Up to 8 patterns can be copied into one.
- Bot capabilities for generating random
Patterns in various styles, in a separate "preset" set of 224 Patterns,
which can then be copied to the main Pattern memory area for editing.
- More elaborate Track editing.
- Other features such as Mutate and Arpeggiator.
- The silver paintwork on the TT-303 appears to be more robust than
that of the TB-303. TB-303 paintwork tended to become discoloured
with lots of handling, I think due to some aluminium flakes being
exposed to the air and touch. I think the TT-303 paintwork will
not have this problem.
- The buttons and knobs are hard chrome plated, like those of the
TB-303. One of the remarkable things about the TB-303 is that the
knobs and buttons could remain in perfect shape after many years of
use, provided they were not in a corrosive atmosphere. Hopefully
the TT-303 knobs and buttons will prove to be similarly robust.
The TT-303's 8 pin DIN MIDI socket, in the location of the original's Sync
socket, accepts a standard 5 pin DIN plug for MIDI In. For MIDI
Out, an adaptor lead with two 5 pin DIN sockets is used, providing MIDI
In and MIDI Out simultaneously.
Our TT-303 came with a 9 volt switch-mode power adaptor which runs
from any mains
voltage. However, I understand that Bass Bots are now being
supplied with non-switch-mode adaptors (which reduces some potential
noise problems) which are set for the mains voltage in the country or
region in which the distributor operates.
The TT-303 comes with a user manual which is clear, concise and well-illustrated. The manual mentions a Drum Drone
TT-606, so keep an eye on http://www.tt-606.com
The Bass Bot
is available from:
Superior Sounds of London (John St London) in the UK:
Rhythm Active in who have a showroom in the main street of Gosford, north of Sydney, Australia:
Syntaur (New Braunfels, between San Antonio and Austin, Texas) in the USA:
in Rognac, near Marseille, France.
(They have a French brochure.)
(Stockholm, Göteborg and Örebro):
It is 31 years since the Roland TB-303 was developed. 1982 is
generally regarded as the year it was released, but my friends and I
first heard of it and the TR-606 from Kraftwerk's tour manager during
their Australian tour in September 1981.
Please keen an eye on the above Cyclone
This is an
historic development in the adventures of the TB-303 and its
successors. Much of the design of the TT-303 - including I assume
PCB and firmware - was done by Rezonance Labs in the USA.
There's a lively discussion of the TT-303 on the Analogue Heaven
mailing list - with the messages in sequential order on multiple pages
or in a threaded structure:
Here is sub-thread in which I report on the capacitors and overall
design of the filter being apparently identical to that of the TB-303:
To join the Analogue Heaven mailing list, please see http://machines.hyperreal.org/Analogue-Heaven/
In mid December 2012, there have been reports (one to me privately,
another on Analogue Heaven) of noise problems with the Volume pot of
the TT-303. Please see this page for my attempt at explaining
This problem is not fixable by replacing components, is not a fault
TT-303 (since much the same thing happens in TB-303s), and will
probably be reduced to a large and perhaps complete
degree by turning the Volume pot dozens or perhaps hundreds of
times. The above page details a mechanical modification to the
Volume knob itself which eliminates the problem. I understand
that this technique has been adopted in Bass Bot production.