Thermionic Culture Fat Bustard MkII All-Valve Passive Input Summing Mixer

The Thermionic Culture Fat Bustard MkII is a 14-input all-valve passive input summing mixer offering a range of processing controls over the stereo output that goes well beyond channel summing. The summing stage uses a pair of 5965 valves and the output stage uses a pair of 6SN7 valves—a combination chosen for its large headroom and smooth response—with semi-floating inputs and unbalanced outputs. Beyond summing, the Fat Bustard MkII provides varislope EQ curves for independent top and bass lift and cut, an Attitude harmonic distortion control for the stereo summing stage, a stereo spread control with selectable frequency range, a Bass to Centre function for low-frequency mono summing, a stereo balance control, and a 31-position ELMA output level switch. The MkII version adds a monitor output with level control and int/ext switching, useful for monitor connectivity or as an insert in/out switch.

Key Features

• 14 inputs — 4 stereo inputs; 4 mono pan-able inputs; 2 Aux inputs with pan switch
• All-valve summing and output stages — summing: pair of 5965 valves; output: pair of 6SN7 valves; large headroom and smooth response; semi-floating inputs, unbalanced outputs
• Varislope EQ curves — top and bass lift — as each control is increased, the peak frequency of the curve becomes more extreme, adding heavier bass or brilliant top without the hardness found in solid-state EQ; bass and top cuts are independent of the lifts
• Attitude control — switched harmonic distortion in the stereo summing stage; adds 2nd harmonic content (subtle at low positions, aggressive at high positions); all controls affect both stereo channels equally
• Stereo spread control — continuously widens the stereo image over a selectable frequency range
• Spread filter control — selects the frequency above which widening occurs, from full-band to above 5kHz only; can be used to vary stereo width and tone simultaneously
• Bass to Centre — sums bass frequencies to mono at 2 selectable low-frequency ranges; additional position sums all frequencies to mono
• 31-position ELMA output level switch — precision stepped attenuator for output level control
• Stereo balance control — fine adjustment of left/right output balance
• Monitor output (MkII) — monitor level control with int/ext switch and extra outputs; can be used to connect and control monitors directly, or configured as an insert in/out switch
• Handcrafted in England

Specifications

• Inputs: 14 (4 stereo; 4 mono pan-able; 2 Aux with pan switch)
• Summing Valves: 5965 (pair)
• Output Valves: 6SN7 (pair)
• Input Type: Semi-floating (passive)
• Outputs: Unbalanced; XLR
• EQ: Varislope top and bass lift; bass and top cut (independent)
• Attitude: Switched (stereo summing stage; 2nd harmonic)
• Stereo Spread: Continuous; selectable frequency range
• Spread Filter: Full band to above 5kHz
• Bass to Centre: 2 frequency ranges + all-to-mono
• Output Level: 31-position ELMA rotary switch
• Monitor Output: Level control; int/ext switch (MkII)
• Construction: Handcrafted in England