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Devil Fish mods for the Cyclone Analogic TT-303 Bass Bot

2019-02-25 Robin Whittle


On 28th November 2012 Cyclone Analogic , 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 Fish modifications.

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 are our 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 these knobs.

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

2019-02-25 update:
There is more work to do in order to finalise the modifications.  I will update this page as soon as I have further information. 

We have not yet decided on pricing.  Here is our current plan:

The capabilities will be the  Devil Fish mods as described in the current User Manual ../Devil-Fish-Manual.pdf with the following differences:
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 FLASH memory.

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 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 not exist.

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:
In January and early 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.


Here I note in red some 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 solutions.

The Bass Bot does everything a TB-303 does except:

The synthesiser circuitry is functionally identical to that of a TB-303 except (based on our experience with one unit sent to us in December 2012):
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 in blue:
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:
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 .

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: (photos) in Rognac, near Marseille, France.  (They have a French brochure.) in Sweden (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 Analogic websites.  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 the schematic, 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 .

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. 


This problem is not fixable by replacing components, is not a fault in the 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.

Update history:

© Robin Whittle 2012 - 2019.
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