You know the feeling: you plug your favorite guitar into yet another highly anticipated overdrive pedal, it sounds fantastic for about ten seconds, and then you realize it’s just sitting on top of your tone like a thick, compressed blanket. You’re playing the pedal, but the pedal isn’t playing with you.
Enter the Mosphoros by RhPf Electronics, an independent pedal builder based in Basel, Switzerland. Designed specifically to solve the dreaded “overdrive blanket” syndrome, the Mosphoros is an amp-like, transparent MOSFET drive built for guitarists who control everything from their hands. If you are the type of player who would rather dig in harder than tap-dance on a boost pedal—and someone whose guitar volume knob actually gets used—this new release demands your attention.
Breaking the Mold: Interacting MOSFET Stages
The key difference between the Mosphoros and your standard TS-style or klone pedal lies in how the circuit handles gain. Most conventional overdrives run your guitar’s signal through a single dominant clipping stage, which usually yields a specific character, texture, or flavor.
Instead of relying on a single bottleneck for clipping, the Mosphoros distributes gain across several interacting MOSFET stages. The result is that saturation doesn’t suddenly switch on; it grows organically.
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Pick lightly: The pedal stays remarkably clean and transparent, simply lifting your signal and adding a touch of weight to your core sound.
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Dig in: The pedal responds with gritty, harmonically rich overdrive.
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Roll back: Just like a roaring tube amp, rolling back your guitar’s volume knob cleans the signal right up.
Gain-Intertwined EQ: Shaping the Breakup
What truly sets the Mosphoros apart from the crowded overdrive market is its highly interactive Bass and Treble controls. Rather than utilizing a traditional EQ network slapped at the end of the signal chain to filter frequencies, both the Bass and Treble controls live inside the gain circuit itself.
As showcased in a recent demo by Philip Czarnecki, these aren’t just EQ knobs—they act as frequency-specific gain controls that perfectly simulate pushing different sections of a tube amplifier:
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Drive: Sets the pedal’s overall gain, effectively simulating the preamp section of a tube amp.
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Bass: Increases gain below 1kHz. Turning this up doesn’t just add low-end warmth; it actually simulates pushing the power tubes of an amp, giving your tone more “sponge” and making it effortless to play.
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Treble: Pushes the gain above 250Hz. This reacts similarly to pushing a rectifier tube, adding bite, sizzle, and upper-harmonic presence.
Because you are adjusting how specific frequencies saturate, you aren’t just shaping your tone—you’re dictating exactly where and how the breakup forms. It’s a much more hands-on, amp-in-a-box experience than traditional drives can offer.
Hear it in Action
To hear just how dynamic this circuit is, you can watch Philip Czarnecki run a Les Paul Standard ’50s into a Two-Rock Bloomfield Drive plugin.
Whether he’s pushing an edge-of-breakup tone into cranked-amp territory or using the Mosphoros as a totally clean amp to add gorgeous “bloom” without altering the amp’s natural EQ, the pedal proves incredibly organic and versatile.
Specs, Pricing, and Availability
The Mosphoros features a stunning, minimalist aesthetic designed in collaboration with Manuel Gulman. It looks just as boutique as it sounds, housed in a gorgeous matte black sand-textured enclosure.
RhPf Electronics Mosphoros Specs:
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Circuit: Multi-stage transparent MOSFET overdrive
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Bypass: True Bypass
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Jacks: Top-mounted for optimized pedalboard real estate
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Enclosure: 125B size, matte black sand texture
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Power: 9V DC standard (center negative)
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Current Draw: Under 30mA
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Origin: Designed and hand-built in Basel, Switzerland
Pricing: The Mosphoros is priced at $199 and is available now. You can pick it up at select boutique retailers or order it directly from rhpfelectronics.com.
If you’re tired of overdrives that mask your guitar’s natural voice, the RhPf Mosphoros is exactly what it sounds like: an overdrive built around the idea that the best tone shaping happens at your fingertips, not on the pedal.
#RhPf Electronics #Mosphoros
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