The following is via Robin Whittle, creator of the renown
Devil Fish mods for the original TB-303. Robin plans to make the Devil Fish Mods available for the TT-303 Bass Bot as well.
"I have done a preliminary circuit tracing of most of the Bass Bot and compared its function and signals with those of the TB-303.
The Bass Bot is not claimed to be a replica of the TB-303 - it just looks that way. Please note that what I wrote relates to a single machine from the December production batch. There is a new batch just about to be made and I understand that there are some hardware and firmware changes - but I don't know what they are. What I wrote here may be updated in the future, may not be complete or accurate, and may not reflect the behavior of all Bass Bots:
http://www.firstpr.com.au/rwi/dfish/TT-303/#diffs (
Update: see the link for additional assessments added after this post)
The Bass Bot does everything a TB-303 does except:
It does not receive Roland/DIN Sync.
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.
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):
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 significantly.
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.
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.
The circuitry is in general identical - except of course that different transistor and IC types are used. I didn't find any evidence that these differences result in a different sound.
I will await a machine from the new production batch before I do the detailed work for the forthcoming Devil Fish modifications. Although the modifications will be identical or similar in principle to those for the TB-303, the new machine has totally different component numbering, different layout, and almost all the components are surface mount. It will be a while before I finalize the modifications.
I have added the Swedish distributor Jam.se to the above page."
Update: you'll find updates to Robin's assessments on his TT-303 page
here.
The TB-303 (named for "Transistor Bass") was originally marketed to guitarists for bass accompaniment while practicing alone. Production lasted approximately 18 months, resulting in only 10,000 units. It was not until the mid- to late-1980s that DJs and electronic musicians in Chicago found a use for the machine in the context of the newly developing house music genre. At the time they were very cheap, which helped to contribute to their popularity. The TB-303 is considered a collector's item today, often valued at US $1000 to $3000. An example recently sold on eBay for US $2,275.00. Phuture's "Acid Tracks" is widely acknowledged to have been the first Acid House recording to incorporate prototypical TB-303 sounds. Earlier recordings featuring the TB-303 can be traced back as far as the early Electro scene, including artists such as Ice T, Newcleus, and Mantronix, as well as pop musicians such as Heaven 17 and Section 25. In the early 90's, as new Acid styles emerged, the 303 was often overdriven, producing a harsher sound. Examples of this technique include Hardfloor's 1992 EP "Acperience", and Interlect 3000's 1993 EP "Volcano". The well-known "acid" sound is typically produced by playing a repeating note pattern on the TB-303, while altering the filter's cutoff frequency, resonance, and envelope modulation. The TB-303's accent control modifies a note's volume, filter resonance, and envelope modulation, allowing further variations in timbre. A distortion effect, either by using a guitar effects pedal or overdriving the input of an audio mixer, is commonly used to give the TB-303 a denser, noisier timbre--as the resulting sound is much richer in harmonics. The head designer of the TB-303, Tadao Kikumoto, was also responsible for leading design of the TR-909 drum machine. " No details on the SBX-80. If you know more, feel free to comment. via ni hao in the comments of this post.
"The Roland TB-303 is a machine like no other. With an unmistakable sonic signature brimming with warmth, energy and character, the iconic silver box defined the acid house movement of the late 1980s. Widely misunderstood when launched in 1981, the true revolution began several years later when electronic music producers rediscovered the quirky box, unleashing the hypnotic, liquid sound that captivated a generation. While we may never really understand why the 303 sound makes people want to dance, there is no denying its power, influence, and unwavering ability to get a party started. It just works, even after all this time.
"For sale we have a Quicksilver upgraded Roland TB-303 analog synthesizer. The machine has a lot of cosmetic paint wear all over the case (see pictures). Functionally the machine is excellent, with new tact switches, some new potentiometers, tuned and tested! This 303 has been modified with the Quicksilver 303 CPU upgrade! A great way to get this amazing upgrade without having to send away your 303 or deal with installation. This machine has also had the switches replaced with new ALPS sealed tact switches, so there aren't any problems with buttons double triggering. The Quicksilver 303 CPU adds support for: * MIDI input/output * USB-MIDI * realtime pattern editing * pattern MIDI output * sysex pattern dumps * realtime mode switching * filter control over MIDI * pattern randomize * MIDI sync * updateable operating system ... and much, much more. With the Quicksilver 303 upgrade, the 303 has become an amazing interactive live performance synthesizer. You can create and edit patterns without ever stopping the sequencer. You can find out more about the Quicksilver 303 upgrade here: http://www.socialentropy.com/quicksilver A video showing some of the cool things the Quicksilver 303 is capable of: Quicksilver 303 MIDI CONTROL This TB-303 is in excellent functional condition, with substantial paint wear on the machine. There is also a chip on the front corner (see photos). Includes the original vinyl Roland carry case in OK condition. Includes the Quicksilver 303 MIDI dongles. Includes a NEW genuine BOSS PSA-120S power supply." 
