Dunlop M77-U
Dunlop M77-U
Dunlop M77-U
Dunlop M77-U
Dunlop M77-U
Dunlop M77-U
Dunlop M77-U MXR Custom Badass Modified Overdrive Pedal
Product images are provided for reference and may not represent the exact model, configuration, or included components.

At A Glance

Input Impedance
1 MΩ
Output Impedance
Noise Floor
>87 dB
Tone Control
± 8 dB at 2.7 KHz
100HZ Control
± 24 dB at 100 Hz
Bump Button
+6 dB low ~ mid boost, -3 dB at 540 kHz
Gain Control
± 25 dB range at 100 Hz
Bypass
True Hardwire
Power Draw
Power Supply
9 volt DC
Description

Dunlop produced the M77-U as part of the MXR line, positioning it as a modified take on a classic overdrive circuit. The Custom Badass Modified Overdrive sat within MXR's effects pedal catalogue as a feature-expanded overdrive unit, distinguished from a standard overdrive by the addition of dedicated low-frequency and switching controls.

The circuit offered a Gain control spanning ±25 dB range at 100 Hz, a Tone control providing ±8 dB at 2.7 kHz, and a 100HZ control delivering ±24 dB at 100 Hz — the latter being the primary modification over a conventional overdrive topology. A Bump button engaged a +6 dB low-to-mid boost with a -3 dB cut at 540 kHz, allowing further shaping of the low-end character. The unit ran on a 9-volt DC supply, drew less than 4 mA, and employed true hardwire bypass. Input impedance was rated at 1 MΩ and output impedance at under 7.5 kΩ, with a noise floor exceeding 87 dB.

Owners tracing a fault, sourcing a replacement DC jack, or adjusting internal trim components should consult a qualified guitar technician familiar with effects pedal circuitry.

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