The outputSTAGE.
The output stage is part of the voice, even when DIST and TAPE are off. It turns the filtered waveform into a note with level, articulation and character. The VCA follows Gate and Accent; the volume control and transistor amplifier then decide how much of the note reaches the rest of the instrument and how its peaks behave under drive.
The modeled components, their sound and the controls that drive themFrom the filter to the line output.
The selected filter sends audio to a modeled BA662-style VCA. Gate, the note envelope and Accent set the current that controls this VCA, so a note's articulation changes before the main volume control. The audio then passes a low-frequency coupling path and the LEVEL volume wiper. From there it enters a resistor-feedback amplifier built from two modeled transistor stages.
After this amplifier come the optional DIST1–DIST4 circuit, output bass trim, TAPE/CLIP, Echo and Reverb. Turning those later effects off still leaves the VCA and line amplifier in the dry voice. In licensed offline rendering, the active path is processed at 16× and converted to the host sample rate at the end.
The filter has already shaped the oscillator and its overtones.
The note envelope controls gain; large signals meet finite current and voltage headroom.
AC coupling removes slow DC drift, and the volume control sets amplifier drive.
Feedback sets ordinary gain; stronger input can bend and constrain the peaks.
Why Accent changes more than loudness.
The BA662-style operational transconductance amplifier uses an audio differential pair rather than a simple digital volume multiplier. Envelope and Accent currents change how strongly that pair passes the filtered waveform. The model also includes its loaded output mirror and an emitter-follower equivalent, each with finite operating range. At modest signal levels the VCA mostly follows the control envelope. With a larger audio signal or stronger control current, its response can become less proportional.
That is why an accented note can feel denser as well as louder. Accent affects the filter and VCA before the transistor line amplifier; the extra level can then drive the amplifier harder. The result depends on the incoming waveform, pitch, filter setting, note envelope and circuit values. Accent does not impose one fixed distortion sound on every note.
Level first. Character as it is driven.
The volume wiper feeds an inverting, two-transistor line amplifier with resistor feedback. At a comfortable input level, feedback keeps its output largely proportional to the input. The polarity is reversed relative to the amplifier input; this is the expected action of the inverting stage and does not change how the note sounds by itself.
When its input grows, transistor junction behavior and limited output swing make the response bend. The positive and negative excursions can bend by different amounts, and both can be constrained. This creates additional overtones while the loudest peaks gain less level than the quieter parts of the waveform. In Normal quality and offline rendering, CreakBox solves the interacting circuit nodes together; the line amplifier is not simply a tanh function applied to the final audio.
The modeled line coupling acts as a gentle high-pass, about 5 Hz in the current Original circuit. It keeps very slow offset and sub-bass drift from feeding the amplifier. The optional BASS TRIM HP later in the path is a separate control.
From open peaks to a denser note.
With room to move
At lower drive, LEVEL mostly changes loudness. A saw and a square already carry their own overtones from the oscillator and filter, and the output stage passes much of that shape onward. The result can sound open and dynamic even though the modeled VCA and coupling remain active.
When peaks push back
Increasing LEVEL, VOICE GAIN or VolumeOutBoost presents a larger signal to the line amplifier. Peaks then stop growing in direct proportion to the control movement. You may hear a thicker edge, a more compact Accent and a different balance between the body of the note and its bright attack. The change can be subtle or obvious depending on the source.
This is saturation with instantaneous peak compression, not a separate compressor with threshold, attack and release knobs. A short peak can be restrained while the lower-level part of the same note still rises. Inversion, the filter's own harmonics and a later DAW gain change can all make a waveform look different; the audible change here comes from how the VCA and amplifier respond to their actual input level.
DIST1–DIST4 and TAPE/CLIP can add their own character after the line amplifier. Their contribution is separate from this dry output-stage behavior.
Which control changes which part?
LEVEL on Perform is the main volume-wiper control. It sets drive into the two-transistor amplifier. In Circuit Bend, VolumeOutBoost adds 1× to 10× gain after that wiper and before the amplifier; VOICE GAIN changes the voice level reaching this part of the path. These controls can all increase amplifier drive, but they act at different points. A DAW channel fader after CreakBox changes listening level without undoing saturation that has already happened inside it.
BASE VCA and ACC VCA set the ordinary and Accent contributions to VCA control current. BA662 SENS changes how strongly that current controls VCA gain, while BA662 DRIVE changes how soon the audio pair reaches its nonlinear region. These controls can change articulation and timbre before the volume wiper.
BA662 MATCH offsets the pair and changes the balance between positive and negative excursions; it can make even overtones more prominent. BA662 NOISE sets low-level open-VCA noise. LINE OUT HP adjusts the coupling corner ahead of the line amplifier. The separate BASS TRIM HP removes bass later in the path and can be switched fully OFF.
Where to find them: Circuit Bend and Quick assignments require a Full license. Search by the names above; each control's reset follows the active circuit configuration. The embedded Original profile sets VolumeOutBoost to 10× and VOICE GAIN to 1.3. A saved project or custom configuration may use different values.
Hear the output stage on its own.
Turn DIST and TAPE/CLIP off and repeat the same note or short pattern. Raise LEVEL or VolumeOutBoost gradually while keeping the filter and Accent settings fixed. Listen to the attack, the low body and how much louder the strongest peaks become. After each change, match the playback loudness with your DAW fader before judging the tone.
For a more focused comparison, return to the circuit's reset values between changes. Try BA662 DRIVE to hear the VCA pair respond sooner, then BA662 MATCH to hear the effect of imbalance. Keep notes on the waveform, cutoff, resonance and Accent setting: these determine what arrives at the output stage in the first place.