Thermionic Culture Culture Vulture Valve Harmonic Distortion Unit

The Thermionic Culture Culture Vulture is the original studio unit dedicated entirely to adding valve-produced harmonic distortion to program material, with no solid-state components in the signal path. Introduced in 1998 and largely unchanged since, it remains the definitive tool for applying controlled, musical valve saturation to individual tracks or buses. The heart of the unit is a 6AS6 distortion valve whose operating point is set by a front-panel Bias control, with a milliameter showing the current in real time; the relationship between bias current and distortion character gives the Culture Vulture an unusually wide and expressive operating range. A Low-pass filter, Drive control, Overdrive switch, and Output Level knob provide comprehensive control over the intensity and tonal quality of the effect, and a Bypass switch allows direct A/B comparison with the unprocessed signal.

Key Features

• Three distortion mode settings — T: triode mode, produces musical 2nd harmonic content suited to warming up a sound; P1: pentode mode, shifts toward odd harmonics for a more aggressive character while retaining valve quality; P2: “No Holds Barred” configuration, an unusual valve setup that can produce an extra octave of harmonic content at higher bias settings
• Bias control with milliameter — sets the current through the 6AS6 distortion valve; low current (starved) produces a thin, easily breaking sound; high current (over-fed) gives a fat, bloated character; medium current (0.25–0.3mA) minimizes distortion and is ideal for gentle warming
• Low-pass filter — 12dB/oct slope; removes unwanted frequencies above 6kHz or 9kHz (selectable) for a rounder, smoother result when heavy distortion is in use
• Drive control and Overdrive switch — controls the amount the input signal is boosted before reaching the 6AS6 valve; wide range of overdrive intensity available
• Output Level control — adjusts signal level going to the output valve; set to 8+ for low distortion use; reduce when Drive is increased to manage output level; note: when P2 is selected, standard Output Level interaction does not apply
• Bypass switch — completely removes the Culture Vulture from the signal path for accurate before/after comparison
• No solid-state components in the audio path

Specifications

• Distortion Valve: 6AS6
• Distortion Modes: T (triode); P1 (pentode); P2 (no holds barred)
• Bias Control: Continuous; milliameter metering (recommended operating: 0.25–0.3mA)
• Low-Pass Filter: 12dB/oct; 6kHz or 9kHz (selectable)
• Drive: Continuous; Overdrive switch
• Bypass: Hard bypass switch
• Circuit Type: All-valve; no solid state in audio path
• Construction: Handcrafted in England