Buchla and Tiptop Audio — 266t Source of Uncertainty
Download the Manual PDF (Source of Uncertainty - Model 266t)
Buchla/TIPTOP Source of Uncertainty 266t – Cheat Sheet
Overview
The 266t Source of Uncertainty is a classic random voltage generator with multiple independent sections, ideal for generative and experimental patches. It features several types of noise, fluctuating and quantized random voltages, sample & hold, integrator (slew), and elaborate stepped random voltage generators.
Panel Sections, Jacks & Controls
1. Noise Source
- Outputs (3)
- Blue Noise: -3dB/oct, low-frequency biased
- Pink Noise: Flat (equal across frequency)
- White Noise: +3dB/oct, high-frequency biased
2. Fluctuating Random Voltages
- Inputs
- CV In: 0–10V, controls rate of fluctuation
- Outputs
- CV Out: 0–10V fluctuating random voltage (LED shows rate)
- Knob
- Rate: 0.05 Hz (slowest) to 50 Hz (fastest), sets probable voltage change rate
3. Sample and Hold
- Inputs
- Pulse In: External clock or trigger (2–10V typical Euro signals)
- CV In: Voltage source to sample (±5V recommended for full range)
- Outputs
- CV Out: Sampled/held voltage
- Alt: Alternates sampling to two outputs (ping-pong effect)
- Notes: Pulse “Alt” divides incoming clock to alternate outputs
4. Integrator (Slew Limiter)
- Inputs
- In: Voltage to smooth (stepped or discrete)
- CV In: 0–10V, controls amount of smoothing
- Output
- Out: Slewed/smoothed voltage
- Knob
- Slew Rate: 0.01 (none) to 10 (max glide)
- Trim
- TR1: (rear trimmer, sets overall smoothing range)
5. Quantized Random Voltage
- Inputs
- Pulse In: External clock or trigger
- CV In: 0–10V, controls number of steps
- Outputs
- n+1 Out: 5V range, locally scaled (sparser quantization)
- 2^n Out: 10V range, evenly distributed
- Knob
- Steps: Sets number of voltage steps (1–6)
6. Stored Random Voltage
- Inputs
- Pulse In: External clock or trigger
- CV In: 0–10V, controls right output distribution skew
- Outputs
- Left Out (Linear): Evenly distributed random 0–10V
- Right Out (Skew): Skewed distribution based on knob/CV
- Knob
- Distribution Curve: CCW = low skew, Middle = bell, CW = high skew
Voltage Ranges & General Notes
| Section |
Input Voltage |
Output Voltage |
| CV Inputs |
0–10V typical |
|
| Noise Out |
|
±5V |
| Fluctuating |
0–10V (CV in) |
0–10V |
| Sample & Hold |
2–10V (Trig in) |
±5V |
| Integrator |
0–10V (CV in) |
0–10V |
| QRV/SRV Outputs |
|
0–10V |
- Pulses: Any typical 5V–10V Euro triggers/clocks.
- CV Inputs: Respond to unipolar 0–10V (Euro standard).
- Outputs: Most outputs are 0–10V, except noise (bipolar).
What Each Section Does
- Noise: Raw random voltages, for audio or sample sources.
- Fluctuating: Smoothly morphing random voltages.
- Sample & Hold: “Freeze frame” sampled value at pulse input.
- Integrator: Slew/portamento for incoming steps.
- Quantized Random: Stepped random voltages (adjust step count).
- Stored Random: Stepped random with variable statistical distribution.
Physical Specs
- Size: 24 HP
- Depth: 25mm
- Power: +12V/150mA, -12V/100mA
Useful Patch Ideas
- Self-generating/random melodies: S&H/Quantized/Stored sections into pitch or filter cutoff.
- Generative clocks: Quantized/Stored into tempo division/multipliers.
- Automated parameter movement: Fluctuating random into panning, reverb, etc.
- Slew beats: Integrator for smoothed parameter automation.
Generated With Eurorack Processor