KEELEY Octa Psi 3 Mode Transistor Fuzz Circuit
PRODUCT OVERVIEW
CONTROLS
FUZZ
The result of stacked gain stages. More is usually better.
LEVEL
Controls volume of fuzz. Clockwise for more.
TONE
It’s a light and dark thing. Classic scooped-mids sound when the tone control is at noon. Turn Clockwise for more treble and bass cut, Counter-clockwise for more bass and rolled-off treble.
FUZZ TOGGLE
- Scoop – standard scooped fuzz.
- Punch – bass-boosted fuzz.
- Psi – fuzz with maximum undertones.
BLEND
Controls the volume level of the pitches, intervals, or octaves created. Push down the BLEND control while rotating to adjust which intervals are voiced. When the OCTAVE TOGGLE is in the UP or DOWN positions, you can toggle between major and minor voicings by pushing down and turning the PUSH-BLEND control Fully Clockwise. When the OCTAVE TOGGLE is in DUAL position, the PUSH-BLEND control is a linear volume tilt control between the red and white colored intervals on the PITCH MATRIX.
PITCH
Select from 8 modes, each with UP, DUAL, or DOWN modes via the Octave Toggle. (See PITCH MATRIX below.)
OCTAVE TOGGLE
- UP – Pitch-up voice-only intervals in red are only available when Push-Blend is fully CW).
- DUAL – Both up and down pitches (Push-Blend and rotate to adjust Tilt Volume of intervals).
- DOWN – Pitch down voice only intervals in red are only available when Push-Blend is fully CW).
PITCH MATRIX
ADVANCED
REMOTE JACK
Plug a TRS cable into the Remote jack to control the Octave and Fuzz bypass via remote switcher with the Tip to control the Fuzz and the Ring to control the Octave. By default the jack works with momentary switches. To use latching switches, press and hold the Octave switch while applying power to the unit. The Octave LED will flash twice to indicate momentary and three times for latching.
CONTROL JACK
Plug a TRS expression pedal into the Control jack to control the pitch shift amount. The range runs from unison at heel down to full pitch shift at toe down. The maximum pitch shift range is dependent upon the encoder setting. Plug a TS cable into the Control jack to use an external stomp switch to change effect order. The LED for the effect that is first in the chain will flash three times when a change has been made. Factory default is Fuzz into Octave.
EFFECT ORDER FUZZ = OCTAVE
Press and hold both Fuzz and Octave switches to change the effect order. The LED for the effect that is first in the chain will flash three times when a change has been made. Factory default is Fuzz into Octave.
WET+DRY/ALL WET
To add or remove the dry signal from the Octave effect double tap the Blend control push switch. The Octave LED will flash two times for All Wet and three times for Wet + Dry. The factory default is Wet + Dry.
VOLUME TILT CONTROL
When the toggle switch for the Octave is in the DUAL position the volume between the two pitches can be altered. Simply press and hold the Blend switch and move the Blend control. When the Blend control is at Noon the volumes of both pitches are equal. As the Blend control is moved CW of Noon the low pitch level is attenuated. As the Blend control is moved CCW from Noon the high pitch level is attenuated. In UP or DOWN positions, to activate the red or minor intervals you press down on the Blend switch and rotate fully clockwise.
OCTAVE / PITCH RAMP SPEED – MOMENTARY / LATCHING MODE
Change between Momentary or Latching Mode by pressing and holding the Fuzz switch for 1 second. To change ramp speed, press and hold the Octave switch then adjust the Blend control. The Octave LED will flash three times for Momentary Ramp Mode and twice for Latching Mode. The shortest time is full CCW at roughly 5ms, while the longest time is full CW at roughly 2 seconds.
TRUE BYPASS / BUFFERED BYPASS
To change between True Bypass or Buffered Bypass, unplug power then hold Fuzz switch while reapplying power. The Fuzz LED will flash two times for True Bypass and three times for Buffered Bypass. The factory default is Buffered Bypass.
FACTORY RESET
Unplug the power, then press and hold the Octave and Fuzz Bypass switches while applying power to the unit to perform a factory reset. The Octave and Fuzz LEDs will alternately flash three times to indicate a successful reset.
Documents / Resources
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KEELEY Octa Psi 3 Mode Transistor Fuzz Circuit [pdf] Instruction Manual Octa Psi 3 Mode Transistor Fuzz Circuit, Octa Psi, 3 Mode Transistor Fuzz Circuit, Transistor Fuzz Circuit, Fuzz Circuit, Circuit |