The Radial Voco-Loco is a microphone preamp with a built-in effects loop, made by Radial Engineering, that lets you plug a mic into your pedalboard. Your voice (or harmonica) goes in through an XLR input, gets converted to an unbalanced instrument-level signal, runs out to your delay, reverb or distortion pedals, comes back, and then feeds a balanced line-level XLR output straight to the PA12. Radial describes it as "a studio quality preamp that has been carefully disguised as a foot pedal"2.
The original Voco-Loco has been discontinued and is no longer shipping; it has been superseded by the Voco-Loco Mk2, an updated version that keeps the same concept13. This page covers both.
What it does: guitar pedals on a microphone
Guitar pedals expect an unbalanced, instrument-level signal on a 1/4" jack, and a microphone delivers a balanced, low-level signal on an XLR. The Voco-Loco sits between the two worlds. The mic feeds its preamp, the signal is sent out of unbalanced 1/4" jacks to your pedals, and the loop returns into the unit, where a tone control lets you tame the effects signal before everything reaches the PA52.
The point is that the dry microphone signal stays clean. Radial states the dry signal is delivered to the PA without distortion or artifact, so you can switch the effects in only when you want them2. Radial positions the unit for singers adding echo, reverb or distortion to a vocal, and for harmonica players adding chorus, overdrive and reverb to harp solos1. It works with both dynamic and condenser microphones, and Radial says it tested a wide range of popular stage and studio mics with excellent results in all cases12.
The controls and footswitches
The original Voco-Loco's front panel is built around two footswitches and a small set of controls5.
| Control or switch | What it does |
|---|---|
| Loop Wet/Dry footswitch | Turns the effects loop on or off with the wet/dry mix engaged5 |
| Mute / All Wet footswitch | Activates the MUTE or ALL WET function5 |
| Mute Loop switch | Sets the left footswitch to either Mute or All Wet5 |
| Mic In control | Sets the input level of the mic preamp5 |
| Send / Receive controls | Adjust the level going to the pedals to optimize signal-to-noise and reduce distortion5 |
| Mix control | Sets the wet/dry mix between the unprocessed vocal sound and the effects loop5 |
| Low / High EQ | Dual band shelving EQ to add bass and warm the voice, or add sparkle for extra cut5 |
| Tone control (loop return) | Tames the effects signal once the loop is brought back2 |
| 180° switch | Reverses the polarity of the effects loop so pedals stay in phase with the vocal mic5 |
| 48V switch | Recessed switch that turns on phantom power for a condenser microphone5 |
| Lift switch | Lifts pin-1 on the XLR to help eliminate ground loops5 |
The Mk2 carries the same ideas forward: its primary footswitch toggles the effects loop on or off, a dry-wet mix control balances the signal to suit, and a 2-band EQ makes tone adjustment effortless64.
Power and connections
The original Voco-Loco comes with an external 400mA 15VDC supply, center positive52. The Mk2 still ships with its own 15V PSU but adds flexibility: its power input accepts 9V and 18V pedalboard power supplies as well34.
Both versions are center positive, the opposite of the center-negative convention on most guitar pedals. Check polarity before plugging the Mk2 into a pedalboard supply, and note that the original is specified only for its own 15V supply526.
Connections are the same idea on both: a female XLR mic input on one side, unbalanced 1/4" send and return jacks for the pedal loop, and a male XLR line output for the PA or mixing console52. The Mk2 upgrades the mic input to a balanced locking XLR6.
Mic preamp specifications
Radial calls the Mk2 "in fact a studio quality preamp"4, and the published measurements back that up. The original and Mk2 share the same headline figures24.
| Specification | Value |
|---|---|
| Audio circuit | Integrated op-amp with Class A FET input circuit24 |
| Frequency response | 20Hz to 20kHz24 |
| Gain | 52dB24 |
| Dynamic range | 100dB24 |
| Maximum input | +10dB24 |
| Clip level | +15dBu24 |
| Equivalent input noise | -120dBu24 |
| Noise floor | -85dBu24 |
| Common mode rejection | -73dB @55Hz24 |
| Phase deviation | 8° @50Hz24 |
| Input impedance | 10K-Ohms, 100K (FX loop)24 |
| Output impedance | 300 Ohms, 3000 Ohms (FX loop)24 |
The Mk2 is built into a 14 gauge steel chassis and outer shell, measures 5.75" x 3.73" x 1.38" (146 x 95 x 35mm), and carries Radial's transferable 3-year warranty4. Radial specifies use in dry locations only, between 5°C and 40°C24.
Phantom power: 40 volts, not 48
The phantom switch is labeled 48V, but Radial is explicit that the Voco-Loco actually generates 40 volts phantom, not 48 volts24. The reasoning is practical: the high voltage used to charge condenser mics in PA systems exists so a condenser can be positioned 200 meters (600 feet) away from the console, which is not needed when the mic cable is short and the unit sits near the musician. Radial chose 40 volts to reduce a power stage that could add noise24.
Versions: the original Voco-Loco and the Mk2
The original Voco-Loco is discontinued and no longer shipping1. The Voco-Loco Mk2 is the updated version3, and the differences Radial publishes are mostly practical:
| Original Voco-Loco | Voco-Loco Mk2 | |
|---|---|---|
| Status | Discontinued1 | Current3 |
| Mic input | Standard XLR female5 | Balanced locking XLR6 |
| Power | External 400mA 15VDC supply, center positive52 | Included 15V PSU, or 9V to 18V pedalboard supplies; 400mA, center positive64 |
| EQ | Dual band shelving Low/High EQ5 | 2-band EQ4 |
| Mix | Mix control for wet/dry5 | Dry-wet mix control4 |
Both share the same preamp circuit, the same measured specifications, and the same core job: putting guitar pedals on a microphone24. An owner's manual is available as a resource on the Mk2 product page3.
Videos
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Questions
Does the Radial Voco-Loco have phantom power?
Yes. A recessed 48V switch on the original turns on phantom power for use with a condenser microphone. The unit actually generates 40 volts phantom rather than the full 48 volts, which is enough for the short mic cables a singer uses on stage. Dynamic microphones need no phantom power at all.
Why does the Voco-Loco use 40V phantom instead of 48V?
Radial chose 40 volts to reduce a power stage that could add noise. The high voltage used in PA systems exists so a condenser mic can sit up to 200 meters (600 feet) from the mixing console, which is not needed when the mic cable is short and the unit sits near the musician.
Can you use the Voco-Loco with a harmonica mic?
Yes. Radial says the Voco-Loco lets you add chorus, overdrive and reverb to harp solos, and it works with dynamic and condenser microphones, which covers the dynamic elements common in harp mics. Radial also states it tested a wide range of stage and studio mics with excellent results.
Can the Voco-Loco run from a 9V pedalboard supply?
The Mk2 can. Its power input accepts the included 15VDC supply or 9V to 18V pedalboard power supplies. The original Voco-Loco shipped with an external 400mA 15VDC supply, center positive, and Radial gives no pedalboard-supply rating for it.
Is the original Radial Voco-Loco discontinued?
Yes. Radial states the original Voco-Loco has been discontinued and is no longer shipping, and that it has been updated. The current version is the Voco-Loco Mk2, which keeps the same mic preamp and effects loop concept with a locking XLR input.
What does the 180° switch do on the Voco-Loco?
It reverses the polarity of the effects loop so the signal coming back from your guitar pedals is in phase with the vocal mic. This matters when a pedal flips phase, which can thin out the sound when the wet and dry signals combine.
Sources (6)
- Voco-Loco, Radial Engineering, 2026-02-11
- Voco-Loco Specifications, Radial Engineering, 2022-11-08
- Voco-Loco Mk2, Radial Engineering, 2026-03-16
- Voco Loco Mk2 Specifications, Radial Engineering, 2026-02-17
- Voco-Loco Features, Radial Engineering, 2023-03-13
- Voco Loco Mk2 Features, Radial Engineering
