ACV-1

100% Analog BBD Based Chorus / Vibrato Pedal

The ACV-1 is a marriage of vintage audio processing techniques and advanced, high-tech electronics. It is designed using modern, quality components for uncompromising sound, features, and reliability. We started with a studio-grade MN3007 BBD, unlike the lower cost MN320x pedal-grade BBDs found in most stompboxes. We powered it with a clean,
high voltage 15V power supply. Next, we coupled it with a special blend of two tightly tuned high-Q 5th order anti-alias and reconstruction filters, a compandor with emphasis/de-emphasis, VCA feedback control, a unique 5-amp high current BBD driver, and an analog clock with exponential modulation technology to obtain unprecedented sound and richness, clean, precision regeneration, and true fractional delay in a compact footprint. 

TIME: The TIME knob adjusts the center delay time from ~3ms to ~60ms (more using LFO and control voltages). If you modulate the delay time while playing, you will also notice a pitch change as the signal currently captured in the BBDs is spit out faster or slower, therefore compressing or expanding the delay time. Between about 9:00 and 3:00 produce
chorus sounds. Further CW becomes more of a slap back, while CCW more flanging or comb filter.

PHASE SWITCH: selects whether the delayed sound mixes and feeds back in phase or out of phase. This difference is most pronounced with shorter settings of the time knob or higher amounts of feedback. With shorter time and lots of feedback this can produce a very vocal like quality similar to a talk box. It is also more pronounced on bass notes than higher pitch notes.

FEEDBACK: The FEEDBACK knob affects how much post TONE signal is fed back into the buckets. It equates to the regeneration knob on a flanger and creates deeper time-based peaks in the signal. At longer delay times it acts more like a delay feedback control providing multiple repeats. At extreme settings it may go into self-oscillation providing drone tones that are affected by the time knob setting. Try it out, get lost. Come back after
and read the next section.

RATE: The RATE knob adjusts the speed or rate of modulation from about 0.10Hz to 15Hz (wider range via control voltages). Lower settings provide a slow whoosh or a rhythmic pitch shift. Medium speeds provide a chorus or vibrato effect while faster rates provide a
gargle or, bubble sound.

AMOUNT: The AMOUNT knob controls the depth or range of pitch movement at the speed of the LFO, or the amount of effect. Use low amounts for subtle shimmer and larger amounts for vibrato or octave or greater pitch shifts or spaceship warbles.

LFO SHAPE SWITCH: Selects a triangle wave (up), slewed square wave (middle), or a sine wave (down). Use triangle wave for traditional gradual ramped chorus type modulation, square waves for rapid pitch jumps and sine for a smooth continual movement vibrato or flange sound. 

MIX: The MIX knob provides a-faded wet/dry mix between the delayed wet and clean tone. A 1:1 mix, providing the deepest comb notches, is at about 11:00 and not 12:00. It may be easier to find this with shorter delay times. When turned fully CW the ACV-1 will produce vibrato effects similar to a rotating speaker.

Note: If you are applying a sustained steady pitch to the ACV-1 and have the MIX knob set near 12:00, you may find that the direct and delayed signals alternately will reinforce or cancel each other as the DELAY TIME is varied. This is a normal result of mixing a steady pitch with a delayed replica of itself. This phase cancelation is the chorus/delay equivalent of “standing waves” in a reverberant room.

TONE: The TONE knob is a continuation of Hawker’s highly acclaimed ADG-1 tone control that has been re-voiced slightly higher for the ACV-1. It is a modified, non-symmetrical, “tilt type” filter with a soft curve and center flat position. It provides both high pass and low pass control with a knee around 740Hz. It is placed after the bucket and INSIDE the feedback loop and will bring out or dampen the delayed mix allowing it to become more present or fit under your playing. Extreme settings of this will accentuate the feedback amount and cause self-oscillation.