The Asheville Music Tools APH-12 Plus is a dynamic phase shifter pedal: a 100% analog signal, modulation and control path built around an all-pass filter network with a selectable number of stages from 1 to 121. Asheville Music Tools describes it as an analog phaser toolkit that builds on the Purple Phaze lineage, with expanded stage selection and new modulation options1. At its core it delivers the classic 12 and 6-stage phaser sound with warm overdrive on tap, plus vocal and filter sounds rarely heard in phasers2.
The stage count is the headline. A 12-position rotary selects the number of phasing stages, and on the Plus a second selector opens the full range from 1 to 12 stages, adding the previously missing 7, 8, 10 and 11 stage settings13. Odd stage numbers run out of phase1. Asheville Music Tools describes the character as thinner and quicker at lower stage counts, growing thick, vocal and almost synth-like as you climb higher1.
What the APH-12 Plus does
The Drive knob controls a JFET-powered preamplifier with a second JFET saturation circuit, good for up to 30dB of boost with increasing saturation, usable for level matching or to add harmonics to the filters2. Guitar Pedal X's review identifies Drive as a JFET preamp4.
The controls
| Control | What it does |
|---|---|
| Stage options | 12 stages, 7 to 11 on the expansion switch; odd numbers out of phase1 |
| MOD switch | LFO selector: Fast, Slow, Envelope1 |
| ENV#1 | Positive SWEEP control of modulation, fast attack, medium release1 |
| AMOUNT | LFO depth control from OFF to about 60% of SWEEP1 |
| SWEEP | All-pass filter / manual control; center 25Hz to 10kHz typical, 3Hz to under 50kHz with LFO, envelope or external control voltage14 |
| Resonance | Feeds signal back into the filters to set intensity; extreme settings produce self-oscillation with drone tones tuned by the SWEEP knob2 |
| Drive | JFET preamp with saturation circuit, up to 30dB of boost2 |
| MIX switch | 3 positions: FX/mostly dry, 50/50, VIB/100% wet2 |
| Expression / CV | 4-way switch assigning Sweep, Resonance, Rate or Amount, additive to the front panel knob1 |
The right toggle selects three mix modes3, and the Phase Mode setting is a balanced mix calibrated for deep phasing5.
Power and connections
The APH-12 Plus runs on 9V DC from a standard center negative 2.1mm x 5.5mm barrel supply1. Current draw is under 140mA, 90 to 115mA typical, with up to 200mA at startup1. Input impedance is over 1MΩ and output impedance is 1KΩ maximum, with a maximum output signal of -0.9dBµ / 0.7Vrms1.
The startup draw of up to 200mA means a power supply rated for the typical current may sag at power-on. Plan headroom accordingly, and note there is no battery option: it is a barrel-only pedal1.
The expression jack is a TRS input usable with either an expression pedal or control voltage, with a CV range of -5V to +5V, the control input on the tip and a current-limited ~5V output supplied on the ring1. The 4-way switch assigns the external control to Sweep, Resonance, Rate or Amount, and the external control is additive to the front panel knob, extending its range1.
History and editions
The APH-12 family comes from Asheville Music Tools, whose Analoger APH-12 is the pedal at its base43. A Launch Edition followed, a special launch-day edition finished in numbered units #128 through #148, now discontinued and sold out with no plans to restock2. The standard APH-12 remains in the lineup, and the Plus sits above it: released in limited quantities as part of the maker's small batch series, limited to one per customer or household for individual use rather than resale, its second selector opens the full range from 1 to 12 stages, adding the previously missing 7, 8, 10, and 11 stage settings1.
The Plus itself is released in limited quantities as part of the small batch series, limited to one per customer or household for individual use rather than resale, and is currently sold out1. It is finished in a premium sparkling Cherry Haze finish, with a limited Industrial finish, using sparkle paint from Obscura Manufacturing1.
What reviewers said
Reviews of the family have been positive. Premier Guitar's reviewer wrote that:
"the North Carolina-built APH-12 is an outstanding modulation, filtering, and noise machine"6
Asheville Music Tools describes the Plus as moving from thinner and quicker at lower stage counts to thick, vocal, and almost synth-like as you climb higher, with the second selector opening the full 1 to 12 stage range and bringing the previously missing 7, 8, 10, and 11 stage settings61. The Plus is finished in a premium, sparkling Cherry Haze finish, with a limited Industrial finish also offered, using sparkle paint from Obscura manufacturing1.
Videos
Asheville Music Tools
Mark Johnston
Questions
Is the APH-12 Plus true bypass?
Yes. The bypass footswitch is a mechanical true bypass switch for effect on and off, and the LED indicates LFO rate or envelope pre-amount signal. The same true bypass design appears across the APH-12 family, including the Launch Edition and the standard APH-12.
Is the Asheville Music Tools APH-12 Plus analog?
Yes. Asheville Music Tools describes it as a 100% analog signal, modulation and control path. The underlying APH-12 is built from over 400 components combining vintage audio processing techniques with modern electronics, and press coverage describes it as a fully analog phaser.
Can the APH-12 Plus self-oscillate?
Yes. The Resonance knob controls how much signal is fed back into the filters, and extreme settings produce self-oscillation with drone tones tuned by the SWEEP knob. Guitar Pedal X's review of the APH-12 notes resonance running from off to self-oscillation using the EXP input coupled with knob position.
What is the difference between the APH-12 and the APH-12 Plus?
The Plus adds a second stage selector that opens the full range from 1 to 12 stages, including the previously missing 7, 8, 10 and 11 stage settings, and it draws somewhat more current, under 140mA versus under 125mA for the APH-12. The core circuit, controls and true bypass design are shared.
Does the APH-12 Plus take CV or an expression pedal?
Yes. A TRS expression jack works with either an expression pedal or control voltage, with a CV range of -5V to +5V, control input on the tip and a current-limited ~5V supply on the ring. A 4-way switch assigns the external control to Sweep, Resonance, Rate or Amount, additive to the front panel knob.
Sources (6)
- Asheville Music Tools APH-12 Plus, Asheville Music Tools
- APH-12 12-Stage Phaser, Asheville Music Tools
- Asheville Music Tools Analoger APH-12 Phaser, Delicious Audio, 2026-09-25
- Guitar Pedal X, Guitar Pedal X, 2026-05-07
- Asheville Music Tools APH-12, 12 Stage Analog Phaser, Asheville Music Tools
- Asheville Music Tools Analoger APH-12 Review, Premier Guitar, 2025-07-23
