The TB-303 and TR-606 shared battery power, portable scale and DIN Sync. Together they could operate as a self-contained rhythm section: one stored bass phrases while the other supplied programmable drums. CV and Gate outputs also let the Bass Line control compatible synthesizers, while Mix In could carry another instrument through its final output path.

Kikumoto later recalled that the TB-303's commercial failure ended a proposed TC-404 chord-machine project. The intended family therefore closed before users had finished discovering the two products already released.

Roland's developers did not understand the underground ‘Mid-O fever’ until around 1992. That distance matters. The engineers made a constrained instrument; second-hand owners, clubs and record makers developed the techniques and meanings that followed.

Begin with resonance low and compare sawtooth with square. Next hold the pattern constant while moving only Cutoff. Return Cutoff to the same area, raise Envelope Modulation, and compare short and long Decay. This separates the filter's starting point, distance and duration instead of treating every knob as ‘more acid.’

Program alternating accented and ordinary versions of the same pitch. Keep Resonance moderate, raise Accent gradually, then repeat the test with adjacent accents. You will hear the pattern-dependent accent-sweep response that a simple velocity boost cannot reproduce.

For slide, compare four two-note boundaries: ordinary notes, a slide across a small interval, a slide across a large interval, and a slide into an accented destination. Then place a rest between the same pitches. The rest breaks the connected gate relationship and proves that slide describes a boundary, not a note in isolation.

Knob positions are only the first page of a performance record. Photograph the starting position, then record several passes and note the direction and timing of each control move. On a TB-303, movement is part of the composition.

Before touching memory, write down the Pattern Group, section and number. Photograph or transcribe any valuable phrase. The original hardware has no documented stock export or copy command; paper notation and recorded audio are the dependable backup.

Set Pattern Write, select the address and clear it. Enter pitches in order. Use BACK to correct a pitch-entry error before leaving the layer. Enter the time stream only after the pitch queue is stable: Note begins the next stored pitch, Tie extends the current event and Rest creates silence. Finally step through the pitches with TAP to add Accent or Slide.

Regular Step Mode divides a beat into four positions; Triplet Step Mode divides it into three. A conventional 4/4 bar therefore uses sixteen regular steps or twelve triplet steps. Step Number sets phrase length, and mixed or unequal cycles can create patterns that do not resolve on the expected bar line.

Track memory is a different scale of work. A track stores measure-by-measure pattern addresses plus shifts and navigation instructions such as D.C. and D.S.; it does not contain private copies of the note data. Editing a pattern can therefore change every track that calls that address.

When something sounds wrong, identify the layer before clearing. Correct pitches with a bad rhythm point to the time stream. Correct timing with wrong notes points to the pitch queue. A missing connection between two notes points to Slide, Gate or an inserted Rest. Layer diagnosis is faster and safer than starting again.

The service notes begin with preliminary diagnosis because illuminated LEDs do not prove healthy batteries and unfamiliar programming can resemble a defect. Confirm power, mode, memory address and operating procedure before turning a musical problem into an analogue adjustment.

The factory adjustment sequence checks tempo at TP1, the internal clock at TP2, pitch CV at the output, VCO width and four-octave scale, and VCF response at TP6. Those tests interact with stored Pattern Write data, so the notes tell the technician to locate an empty or easily copied address before calibration.

The published tuning-range specifications disagree: the owner's manual gives ±500 cents, while the service notes say approximately ±700 cents, or a perfect fifth. Preserve that difference rather than forcing the documents to agree; an individual survivor may also have drifted or been modified.

A silent or unstable original deserves conservative diagnosis. Document trimmer positions, change one variable at a time, and leave powered probing, waveform measurement and internal adjustment to a technician who has the correct service notes and equipment. Repair should preserve function and record every change, not erase the object's working history.

The early record is not merely a prelude to Chicago. Singh used the machine inside raga and disco; Ryo Kawasaki placed it in a one-person electronic ensemble; Collins made a pop hook; Martyn Ware used it in Heaven 17; Cenac deliberately moved it above the bass register. The machine had several histories before one of them acquired the name acid.

The two Chicago ‘firsts’ answer different questions. Sleezy D and Marshall Jefferson's “I've Lost Control” is the earlier documented commercial release of the pair. Phuture supplies the stronger participant account of the home experiment, Music Box cassette, audience naming and rehearsed control performance that became “Acid Tracks”. Both facts can stand without turning chronology into a single winner.

Hardfloor later used three TB-303s as counterpoint rather than simply making one line more extreme. Josh Wink planned “Higher State of Consciousness” as a controlled crescendo. Norman Cook's method was to record the hands. These are different compositional answers to the same fact: the panel movement is not decoration added after the pattern; it is part of the work.