Review: Radial Engineering Tonebone Mix-Blender

A utility pedal for mixing and parallel effects processing
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The Radial product line includes scores of switchers, splitters, boosters, buffers, preamps, DIs, interfaces, and hum and buzz eliminators, as well as a number of effects pedals. The Tonebone line alone features more than two dozen devices. Although most of these products are intended for general usage, a significant number of them were designed either to aid musicians and engineers tackle specific problems for which there were previously no solutions, or to facilitate new creative possibilities.

At first glance, the Mix-Blender appears to be little more than a 2x1 mixer with 1/4" inputs and outputs. Such a device could be useful if, say, you perform with two guitars and one amp and don’t want to have to connect and disconnect guitars—especially if they have different output levels and you also have to adjust controls on the amp to compensate. Plug them both into the Mix-Blender, adjust the Level controls, and you’re set. And because those inputs accommodate instrument-and line-level signals, you can do the same with bass, keyboards, and many other instruments.

If your acoustic guitar has both piezo and magnetic pickups (or a high-impedance microphone) with separate outputs, the Mix-Blender can combine them into a single feed to an amp or mixer.

A professional-grade box that mixes the signals from two instruments or pickups into a single-output signal without sucking tone, adding appreciable noise, being a hum and buzz magnet, or introducing other audio bugaboos for $160 is already a decent deal, especially given the Mix-Blender’s discrete Class A circuitry, 14-gauge steel construction, and heavy-duty hardware—but that’s only half the story.

The Radial Tonebone Mix-Blender is a multipurpose utility pedal that can be used with instrumentand line-level sources. Mixing two signals down to one also comes in handy when you want to route both through the same effects chain, which brings us to the Mix-Blender’s ingenious effects loop section. Unlike a typical “loop switcher” that simply allows you to isolate a pedal and switch it in and out of a signal chain, Mix-Blender has a Blend control that lets you retain the original sound while adding the desired amount of processed sound.

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This creates lots of possibilities: When I put a compressor pedal in the loop and used the Blend control to dial in the right amount of squashed signal, it amounted to de facto parallel compression. And I got great results blending a clean guitar tone with a nasty-sounding old Big Muff. Inserting an auto-wah, a ring modulator, a harmony pedal, a synth pedal, and even a volume pedal (as a variable boost) also yielded cool sounds. The footswitch lets you instantly engage or disengage the effects loop.

Additionally, the polarity switch inverts the phase of the loop signal, which is important because, if the polarity of your pedal’s output signal is opposite that of the dry signal, it can seriously compromise the sound, and there is no consistent polarity standard among manufacturers. Moreover, the effects loop’s Send jack may be used to feed a tuner—it is always active—and the Return jack can be used as a third mixer input, with the Blend control serving as its level control.

I tested Mix-Blender using several different guitars, a bass, a synth module, and effects pedals from vintage tone suckers to modern boutique boxes with true-bypass switching; in all cases it performed admirably. Mix-Blender does its job flawlessly and is built to last. What more could you ask for?


Highly versatile. Rugged construction. Superb performance. Excellent value.


None that I encountered.

$169 street

Barry Cleveland is a San Francisco-based journalist, guitarist, composer, recording artist, and audio engineer. Learn more at