• CV and Gate inputs.
    
  
• CV input to turn on Slide.  (2.3 volts turns on the Slide circuit and > 4 volts turns on Gate to tie notes together.)
    
  
• CV input for Accent.
    
  
• CV input for Filter Frequency.
    
  
• Output for Accent.
    
  
• Audio In to filter.
    
  
• Audio In to frequency modulate the filter.
    
  
• Audio Out from filter (pre-VCA).
    
  
• Overdrive pot to control the level of oscillator going to the filter: zero to 66.6 times normal level.
    
  
• Separate control of Main Envelope Generator times in accented and non-accented notes.
    
  
• Volume envelope is no longer fixed, and can be varied from 16 msec through 3 seconds - and to no decay at all, i.e. for notes which last indefinitely.
    
  
• Soft Attack control gives attack times between 0.3 and 30 msec. (TB-303 attack was ~3 msec.)
    
  
• Slide time is variable to five times longer than normal.
    
  
• Variable Filter Tracking causes the oscillator CV to control the filter frequency.
    
  
• Internal Filter FM: a unique approach of AC coupled Filter FM from the audio output of the VCA.
    
  
• The Muffler is a unique post-VCA soft-clip distortion circuit which retains bass response.
    
  
• Push-button to manually activate Accent.
    
  
• Filter can be switched to self resonance.
    
  
• Accent Sweep has three modes and can be disabled.
    
  
• Filter Cut Off pot range doubled to 5 kHz max, and widened to include much lower frequencies.
    
  
• Env Mod pot range extended to include zero and go as high as three times the normal maximum.
    
  
• Bass response is improved.
    
  
• Lithium battery for at least ten years battery backup, so there is no need to install C-cell batteries.
    
  
• The six TB-303 knobs Tuning to Accent are mounted 1.5mm higher, making them easier to turn.  More details: knob-heights/ .
    
  
• The Devil Fish can still sound like a TB-303.  See page 7 of:  Devil-Fish-Manual.pdf .
  

Sound Samples  These are in the sounds/ directory.

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Patch sheets in PDF, GIF and other formats can be found in the patch-sheet/ directory.  Also in this directory you will find a single page PDF file for conveniently writing down every aspect of a TB-303 pattern.   

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An April 1995 early history of the Devil Fish is at dfspank.html.  This includes a report from Atombee on his collaboration with friends, following my advice:

"Investigate feedback loops and tweak them beyond stability.  
Dim the lights, flex your arms, forget about the world outside, 
deliver the punishment your studio/synthesizer needs to find 
its true voice."

Atombee wrote:

By controlling the voltages, we control the frequencies, by 
controlling the frequencies, we can control the human mind. 
.... but God knows the machines took over our brains last 
night ... who is controlled and who is controlling?

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The main images from the cheatsheet card which accompanied the TB-303.  tb-303-card/  This is a mini guide for the TB-303 sequencer's Pattern and Track writing operations.

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Some modifications you can do to the TB-303, including replacement of the push-button switches and installation of an internal dust guard to prolong their life: 303-mods.html. This file also contains a few maintenance tips of interest to technicians - including a new source of replacements for the six small pots: Tuning, Cut Off, Resonance etc.   See also the page on the 6 small pots pot-wear/ .

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A short treatise on the exact timing of the Gate, CV and Slide in the TB-303 sequencer: 303-slide.html.

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Another treatise looking at the TB-303's Accent Sweep circuit and how humans respond to its pattern of pitch variations in the filter when multiple accented notes follow each other in quick succession: 303-unique.html.

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A picture of the excellent 9 volt regulated, 200 mA (milliamp) Boss power adaptor which is best for the TB-303, Devil Fish, TR-606 etc.  In Australia, this is called a PSA-240P.  "Regulated" means that its output voltage is always very close to 9 volts irrespective of load current, up to its maximum of 200 mA.   Most ordinary power adaptors have unregulated outputs, such that with a light load, they may produce 11 volts or more.   There's no way of telling just by looking at an adaptor what voltage it will actually put out when loaded relatively lightly by a TB-303 / Devil Fish.  If it puts out too high a voltage, then this will cause a power transistor in the TB-303 / Devil Fish to overheat, and perhaps to fail.  This over voltage problem is more likely to occur with an adaptor which is rated at 9 volts at a high current such as 500 mA.   Since TB-303s are precious devices, the best approach is to buy a 200 mA 9 volt Boss adaptor!   See the section in the Release Notes about adaptors:  release.html#adaptors .

Also pictured is the Boss Metal Zone MT-2 - a popular distortion and three band EQ distortion pedal which sounds great with the Devil Fish.   This is Chad and Lincoln's, and we had fun in the usual configuration (passing the Devil Fish signal through the Metal Zone), and by sending the Devil Fish's output into the Metal Zone, with the Metal Zone's output going into the Audio In to Filter of the Devil Fish - with the output of the system being the Devil Fish's output, not the Metal Zone's.  This caused filter oscillation right down to low frequencies, irrespective of the setting of the Resonance pot, and we got some great effects where the system would oscillate at both high and low frequencies, and subtle changes in the Devil Fish's pattern (its volume envelope, filter frequency and the pitch of the oscillator) would sometimes perturb the overall system from its normal high frequency mode of oscillation into a totally different low frequency mode.   Feedback, distortion and especially a little delay can give rise to fascinating, complex and sometimes chaotic results.  Lincoln says that Metal Zone aficionados / maniacs sometimes run three of them in series . . . 

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A large picture of the TB-303 circuit boards.  The background is a painting by Adriana Hardy, whose paintings are drawings are at the ../../gallery/ section of this web site.

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You may be interested in my 1993/94 material on Music Marketing via the Internet, especially with electronic delivery: ../../musicmar/ . 

WikiPedia has a good page: en.wikipedia.org/wiki/TB-303 .

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A page which links to other sites regarding TB-303s for sale: tarfo.com/music/?item=TB-303 but since sellers often use "TB303" rather than "TB-303" I suggest you try this as well: tarfo.com/music/?item=TB303 .

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There are a bunch of mailing lists, including Analogue Heaven, at Hyperreal: www.hyperreal.org/music/lists/ .  Hyperreal is an excellent site with many resources of interest to electronic music and rave culture.  In particular, the section on musical instruments is of interest: machines.hyperreal.org.  The TB-303 section is at: machines.hyperreal.org/manufacturers/Roland/TB-303/ . This page includes scans of the TB-303 schematics.

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SonicCouture www.soniccouture.com/en/products/p42-devilfish/ in London have DVD with a bunch of samples of a Devil Fish, which are playable in the Native Instruments Kontakt 4 player.  The player can be downloaded for free, and runs on Windows or Mac machines.  

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The Propellerheads www.propellerheads.se are legendary for ReBirth, the excellent software emulation of two TB-303s, a TR-808 and a TR-909.  

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CustomSynth.co.uk www.customsynth.co.uk  . Please see the photos/  directory for an image of Jeff Toman's radical restoration of a badly worn TB-303 plastic case, for a machine which I had just converted into a Devil Fish.

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The main Roland site is  www.roland.com. From there you can reach the various subsidiaries and distributors in other countries.

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Nothing to do with the TB-303 or Devil Fish, but a fascinating site for musical instrument history:  www.obsolete.com/120_years/  .

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Check out the two oscillator Future Retro 777 sequencer-synthesiser: www.future-retro.com/.  While you can easily plug a synthesiser into the Audio In of the Devil Fish to give you more "oscillators" the main spirit of the Devil Fish is a relatively straightforward oscillator feeding an intense and convoluted process of filtering, distortion, gain control, more distortion and then perhaps some Filter FM.

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A MixMag interview with Hardfloor, the quintessential 303 maniacs: www.techno.de/mixmag/interviews/Hardfloor1.html . 

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A vast array of information about synthesisers, including the TB-303, is at www.vintagesynth.com/  .

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The image below is an illustration of from Volume 2 of the three volume set The Science of Life by H. G. Wells, Julian Huxley and G. P. Wells from 1929-39 (I think). Click the image to see the full page and some more devilish deep-sea creatures.

Q1: "Can the Devil Fish still make the sounds of the TB-303?"

Yes.  See page 7 of:  Devil-Fish-Manual.pdf for how to restrict the Devil Fish to the TB-303 subset. 

It was always my intention that the Devil Fish sound-space be a super-set of the TB-303s, but with repeated fast accented notes, the Version 1.x Devil Fishes did not sound identical to the TB-303.  This lead to the development of the Sweep Speed switch, with the "Fast" mode being that of the version 1.x machines, the "Normal" being that of the TB-303 and the "Slow" being a super wide and sloppy version of the TB-303 response.  This switch was retrofitted to several of the 18 Version 1.x machines, so there remain about 15 or so which cannot do everything a TB-303 can do.  The TB-303 has a weedy bass response due to the low value of capacitors C20 and C21.  These are replaced with larger capacitors in the Devil Fish, so if you want to replicate the TB-303's thinner bass sound, you should use external filtering such as the bass EQ control of a mixer.

Q2: "Does the Devil Fish have MIDI?"

Yes - MIDI In.  Colin Fraser makes a MIDI In and Out retrofit for the TB-303, which I can install within a Devil Fish :  www.sequentix.com .  This is a highly respected system which, in its second version, also enables control of the Filter Frequency via MIDI In.   It requires two 3.5 mm stereo sockets, which can be mounted on the left side of the case.  I make up two special adaptor leads with DIN 5 pin sockets which plug into these sockets.

Q3: "Do you have any TB-303s for sale, or do I know of any?"

Sometimes.  Please contact me if you wish to buy or sell a TB-303 and I may be able to put you in touch with someone.  See the pages mentioned above and above for ways of searching for TB-303s for sale.

Q4: "Are you going to make a standalone Devil Fish?"

One day.  It is a very big project to do it as well as I believe it should be done.

Q5: "Is it OK if a TB-303 has the Kenton CV/Gate/Slide/Accent/Filter input sockets?"

Yes.  Before doing the modifications, I remove the sockets, fill the holes with epoxy, paint them silver and then carefully drill the Devil Fish holes with my template. 

Q6: "My TB-303s pots are stiff. Can you replace them?"

The pots typically are a bit stiff.  The friction in the pot is not caused by the wiper on the carbon track, but by a special part of the shaft rubbing on the case in the presence of high-viscosity silicone grease.  By dismantling the pot, it is possible to remove that grease and make the pot move relatively freely.  However I do not pull pots apart without good reason, because of the danger of damaging them. 

I keep in stock freshly manufactured non-ALPS pots from Technology Transplant www.technologytransplant.biz  as mentioned in the "mods" page #mods .   I can install a new set of 6 small pots - and I have replacement Tempo and Volume pots too. 

Q7: "The TB-303's memory contains precious patterns.  Will they still be there after the Devil Fish modification?"

I don't absolutely guarantee this, but I have procedures for retaining Lithium battery power to the RAM chips at all times, so your data should remain intact.  Be sure to have four good C cells in the machine when you ship it.  Take extra care with the packaging, especially to use tape, packaging or whatever to make sure that nothing can turn the Volume knob to the On condition.  That would flatten the batteries.  The patterns cannot be retained if the 32 bank memory system is installed.  It is best to write your patterns down anyway.  See the pattern sheets mentioned in the Other Information section above.

Q8: "Do you install Ultra Violet LEDs?"

Q9: "What about spare parts, repairs to Devil Fishes and TB-303s"

Certain parts are vital for the TB-303 and cannot be obtained from any source other than by scrapping a TB-303.  The problem parts are:

• CPU chip – an early 1980s NEC 4 bit device with mask-programmed (i.e. the pattern built into the chip at the manufacturing stage) software.  This family of CPUs has not been manufactured since 1984, so even if it was possible to extract the software from a TB-303 CPU, there is no available chip which will run it.
  
  
• The six synthesiser control pots. This style of potentiometer has not been manufactured by Alps since the early 1980s. See #mods about newly manufactured pots.  It is probably impossible to obtain ALPS pots from Roland, but here are the proper Roland spare parts numbers anyway:
• Tuning and Accent pots:  50K linear (Marked underneath as "50KB").  Roland part number 13219331.
• Cut Off and Env Mod pots: 50K log ("50KA"). Roland part number 13219340.
• Resonance pot: Dual 50K linear ("50KBX2").  Roland part number 13219775 (not the 13219774 mentioned in the service manual).  
• Decay pot.  1 meg linear ("1MA").  Roland part number 13219339.
  
  
• The TB-303 case, battery holder cover etc.  The cases can be obtained from a scrapped TR-606, as can the knobs and buttons.  The metal panel part of the case is no longer obtainable.  technologytransplant.com sell an excellent kit with a newly manufactured battery compartment cover, and two battery contacts – the positive metal contact and the negative spring contact.
  
  
• The DIN Sync socket with switch.  (Roland part number 13429706.) The socket is reasonably standard, but its integral dual pole switch is unique and unobtainable.  A workaround is to install a toggleswitch instead.

Fortunately a number of hard- or impossible-to-obtain parts never seem to fail.  These include the Tempo (actually, I have a report of one failing) and Volume pots, the miniature transformer in the power-supply and the dual-transistors in the VCO and filter.  The rotary switches never seem to fail.  ALPS still makes them, but getting one could be tricky.  The 6.5mm Output, Headphone and Input sockets (Roland part number 13449218, or is it 13449217?) are no longer available from the original manufacturer, but they are extraordinarily reliable and I have never had to replace one.

I do not do general service work.  However, I do maintain machines I have modified, and of course repair machines prior to modification. 

See the page on modifications for more details of maintenance, spare parts and alternatives for replacing pots.

Q10: Other maintenance questions regarding knobs, pots, switches, contamination etc.

Do not glue the knobs in place.  Use a little piece of "BluTak" or whatever this grey putty-like substance for holding posters to walls is called in your locality.  Devil Fishes have their knobs secured in this manner. If knobs are hard to remove, grip them with adhesive tape, rather than with pliers.

The Sync socket is secured to the circuit board only by its solder joints, and it is common for these to fracture and so cause intermittent operation.  This can easily be fixed by a technician.  I resolder these joints with every machine I work on, but they may in time become weakened again.

Once the switch replacement and dust-guard work has been done, you should not need to worry about bouncing switches for a long time.  Devil Fishes from 1993 are still working fine, despite many years of intensive use. One machine which I modified and replaced the switches of in 1996 did come back for switch replacement in 2002, but this was a *very* extensively used machine.  The switches are not repairable.  Never spray anything on them.

Battery leakage is a big problem.  Because a Devil Fish (apart from the first 18 Version 1.x machines) has an internal lithium battery there is no need install C cell batteries unless you really want to operate it without a power adaptor.  If you have battery leakage, be sure to have an experienced technician work on your machine to rid it of all traces of corrosive chemicals.  These chemicals can cause lasting damage to circuit boards and components if not removed quickly.  Rainwater is not too much of a problem – let the machine dry and carry on.  Sticky things like sugary drinks require the attention of a technician, who can generally clear it away with water and alcohol.

If your machine fails to operate from C-cell batteries, it is likely that leakage has corroded the spring contact for the negative and/or positive terminal.  Take your machine to a technician!  Another cause of this failure is that on some TB-303s the positive contact is recessed too far for some batteries to reach.  This is easily fixed by dismantling and bending the contact out a little.

See the page on modifications for more details of maintenance, spare parts and alternatives for replacing pots.