The Poly Effects Flat V is a touch-screen, two-channel overdrive pedal built as a collaboration between blues guitarist Josh Smith and Poly Effects, and it reached the market in early 202312. The idea behind it came from Smith wanting a single overdrive pedal to cover all his gain needs, including MIDI switchability3. Poly Effects describes it as a gain pedal with 2 channels and a 100% analog signal path with digital control: the audio stays analog while the screen, presets and MIDI handle everything else1.
What makes the Flat V unusual among overdrive pedals is that its two channels take completely different approaches to gain. Channel A is a transistor-based overdrive stage with selectable clipping diodes, while Channel B is a JFET preamp side, with the JFETs, as That Pedal Show's Mick Taylor put it, "doing the job of cascaded valves that you would get in an amplifier"3. The two channels can stack into one another in either order2.
A two-sided overdrive: diodes and JFETs
Side A is the diode side. It is an overdrive stage where you choose the clipping diode: Schottky, germanium, silicon or LED23. Each diode type has its own clipping character, so one channel already covers a wide range of overdrive flavors before you touch anything else. On That Pedal Show, Taylor walked through the selection: "you've got a selection of four different diodes there, Schottky, diode, germanium, silicon and an LED"3.
Side B is the JFET preamp side. Instead of diode clipping, it uses JFETs doing the job of cascaded valves in an amplifier, and you can stack the two sides in either direction3. That stacking flexibility matters: diode-clip into JFET, or JFET into diode-clip, gives two different gain architectures from the same pedal.
Both channels also carry low and high pass filters, each with a settable cutoff point and resonance3. That lets you shape where the drive sits before it ever hits the rest of your board.
| Channel | Circuit | Clipping | Notes |
|---|---|---|---|
| A | Transistor-based overdrive stage | Selectable diodes: Schottky, germanium, silicon, LED23 | Diode chosen on screen or via MIDI |
| B | JFET preamp | JFET gain stages3 | Stackable with A in either order2 |
Controls, presets and MIDI
The Flat V is controlled through a touch screen with sliders and switches rather than conventional knobs. Poly Effects describes it as a touch-screen 2-channel multi-drive, and Guitar Pedal X's Stefan Karlsson also noted a modulation function in his 2023 year-end roundup, where he called it a "Really smart and innovative touch-screen 2-Channel multi-drive with cool modulation function"7.
Presets are organized as six banks of six presets, which ship including Josh Smith's own presets23. On top of that, every preset has two "Sides": two stored values for each slider that you can blend between, accessed by tapping the big pentagonal icon in the center-top of the pedal5. Tapping the signature button gives access to those two sets of controls within each preset3. Two footswitches, marked "A" and "B", engage the channels5.
MIDI is deep. Poly Effects states the Flat V has full MIDI control over all sliders, switches, channel routing, blending and preset control1. The MIDI channel is set by tapping the LED diode icon three times quickly, then pressing a preset number button to choose a channel from 1 to 68. Selected control change messages from the manual:
| CC | Function |
|---|---|
| 15 / 23 / 31 | Volume, Side 1 / Side 2 / Side 2 Side8 |
| 38 | Set diode: Schottky 0-31, Germanium 32-63, Silicon 63-95, LED 96-1278 |
| 43 | Visualisation mode8 |
| 44 | Battery mode8 |
| 45 | Blending8 |
| 85 | Dump presets8 |
The diode selection is itself MIDI-mappable: CC 38 splits its value range into four bands, one per diode type, so a MIDI controller can switch clipping character mid-song8.
Designed with Josh Smith
The Flat V is a collaboration between Josh Smith and Poly Effects1. Smith wanted an overdrive pedal to cover all his gain needs, including MIDI switchability, and that brief shaped the resulting design3. It reached the market in early 20232.
The design itself carries the collaboration's fingerprints. All presets have 2 sides that allow you to blend between 2 values of each slider1, and the pedal offers a Schottky, Germanium, Silicon and LED diode selection for its clipping1.
What reviewers made of it
On the sound, the reviewers found the Flat V the opposite of a compressed, small-sounding drive: open, raw, uncompressed and extended rather than compressed and small3.
On That Pedal Show, the reviewers found the Flat V the opposite of a compressed, small-sounding drive, describing it as open, raw, uncompressed and extended, and noting that it does not present as a high-gain pedal even though it covers that range3.
Guitar Pedal X named it among 2023's best new boost and overdrive pedals, highlighting the Schottky, germanium, silicon and LED diode selection7.
Videos
Andertons Music Co
R.J. Ronquillo
Josh Smith (Guitarzan)
Questions
Does the Poly Flat V have MIDI?
Yes. The Flat V has full MIDI control over all sliders, switches, channel routing, blending and preset control. The MIDI channel is set by tapping the LED diode icon three times quickly and then pressing a preset number button to choose a channel from 1 to 6. A range of control change messages map to individual functions, including diode selection and preset dumps.
What clipping diodes does the Flat V use?
Channel A is a transistor-based overdrive stage with selectable clipping diodes: Schottky, germanium, silicon and LED. You pick between the four on screen, or over MIDI, where CC 38 sets the diode type across four value ranges, one for each diode.
Is the Poly Flat V analog?
Yes, in its signal path. Poly Effects describes the Flat V as a 100% analog signal path with digital control, meaning the audio itself stays analog while the touch screen, presets and MIDI handle the control side.
How many presets does the Flat V hold?
Six banks of six presets, 36 in total, which ship including presets by Josh Smith. Each preset also has two Sides, two sets of slider values you can blend between, accessed by tapping the pentagonal icon at the center-top of the pedal.
What does the signature button do on the Flat V?
Tapping the signature button gives you access to two sets of controls within each preset. This is the pedal's Side feature: every slider has two stored values per preset, and the signature button switches or blends between them.
Sources (8)
- Josh Smith Flat V, Poly Effects
- Josh Smith teams up with Poly Effects for the Flat V, a two-channel overdrive like you've never seen before, MusicRadar, 2023-01-17
- The Ultimate Do-It-All Overdrive? Poly Flat V, Kernom Ridge, CB Automatone Preamp MkII, That Pedal Show (YouTube), 2023-03-10
- Guitar Pedal X, Guitar Pedal X, 2026-01-14
- Poly Effects Josh Smith Flat V, Delicious Audio, 2023-04-16
- The Ultimate Do-It-All Overdrive? Poly Flat V, Kernom Ridge, CB Automatone Preamp MkII, That Pedal Show, 2023-03-10
- Guitar Pedal X, Guitar Pedal X, 2023-12-16
- Voes | MIDI-CC, Voes, 2024
Shawn Tubbs