The latest from Seymour Duncan, the SFX-04 Twin Tube Mayhem high gain guitar preamp, uses twin sub-miniature USA-made Phillips Sylvania 6205 vacuum tubes to achieve a heavy sound that screams pure metal. These tubes perform under the most turbulent circumstances in terms of shock, vibration, and temperature, so if you've got an extreme show in the middle of a volcano, this is the preamp pedal to use.

Oftentimes, pedal manufacturers put all their focus on tubes, neglecting other components that are integral to incredible sound, but with Seymour Duncan, this is not the case. The SFX-04 Twin Tube Mayhem also utilizes a fully encapsulated, toroidal tranformer to produce high plate voltage resulting in true tube amplification, high dynamic range, smooth tone, and low-order harmonics.

Another feature on the Twin Tube Mayhem is a selectable boost that caters to either 4dB or 8dB boosting. This is ideal for rhythm and lead levels which can be set independently. Add a bypass with gold relays, a silent switching circuit, and a heavy-duty nickel plated chassis, and you've got yourself one mean preamp.

Specs:

• Gain (measured at 1 KHz)
• Before Level Compensation—97 dB
• After Level Compensation—71 dB
• Nominal Output Level—0.25 Vrms (-10dBu) (Nom. Output level measured with 100mV 1 KHz input signal and all controls set to 12 o'clock)
• Max. output level before clipping—5 Vrms (16dBu) (Max. output measured with gain set at 50% and all other controls set full up and boost footswitch set to 8dB)
• Input Impedance: 100Kohms
• 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—11 W
• External Dimensions—7.50" X 6.62" X 1.96" (190mm X 168mm X 50mm)
• Weight—3.15 lbs. (1.43KG)