Seymour Duncan SFX-04 Twin Tube Mayhem Pedal Effect
Before Level Compensation ” 97 dB
After Level Compensation ” 71 dB
(Measured at 1 KHz)
Nominal Output Level ” 0.25 Vrms (-10dBu)
(Measured with 100mV 1 KHz input signal and all controls set to 12 o’clock)
Max. output level before clipping ” 5 Vrms (16dBu)
(Measured with gain set at 50% and all other controls set full up and boost footswitch set to 8dB)
Input Impedance: 100K ohms
THD @ 100mV RMS output ” .5%
Noise @ Output ” 4mV (< 3dB hum content)
Boost Footswitch Gain:
Two selectable boosts, 4dB and 8dB.
No effect on tone, just increased level.
Active Equalization Section:
Bass Control: 126 Hz, Q = 1.5, Gain = ±12dB
Midrange Control: 596 Hz / 1389 Hz, Q = 1.5, Gain = ±12dB
Treble Control: 2.93 KHz, Q = 1.4, Gain = ±12dB
Power Consumption ” 11W
The Seymour Duncan SFX-04 Twin Tube Mayhem is a distortion pedal with a high-quality guitar preamp that includes a built-in boost. Using a duo of premium, mil-spec, subminiature, USA-made Phillips-Sylvania 62051 pentode tubes, the Seymour Duncan Mayhem is a great effect pedal for old-school metal, nu metal, thrash, death, and doom.
The Twin Tube Mayhem pedal has a high-plate voltage and 100% vacuum tube signal path that allow the tubes to operate at their full potential and provide maximum dynamic range. The SFX-04 Mayhem pedal achieves additional gain with a high-voltage, low-noise, and discrete Class A input stage. The solid state input stage increases the resistance of the Mayhem stompbox to microphonic feedback, resulting in maximum dynamic range, the most gain, and the heavy tone you’d expect from a great tube preamp voiced for metal.