The Culture Vulture has earned a universal reputation as the first and only all-valve unit dedicated to producing the finest harmonic distortion available. The Thermionic Culture Ultra Vulture elevates the Culture Vulture design to a new level by making it more suitable for precise stereo applications including mastering where extended frequency response, low noise and recallable settings are essential. Transformer balanced line inputs and outputs on XLR connectors are provided as standard.
Although the unit can operate in a clean mode with less than 0.2 per cent total harmonic distortion, additional valve saturation can be desirable to enhance naturalness and to smooth unwanted digital artefacts.The Thermionic Culture The Ultra Vulture can also be used as a distortion effects unit. The user has full control over the type and amount of distortion it produces, selecting even harmonics, odd harmonics or a combination of both. When underfed, the sound becomes thin and lacks body; when overfed, it becomes richer and more substantial.
A function switch offers two effects positions called P2 and P3. An additional plus ten decibel drive position provides some of the bite of the Overdrive setting but with significantly less noise. When the plus ten decibel position is selected, a Presence switch becomes available. A minus ten decibel output switch allows the unit to be driven into extreme distortion while maintaining an easily achieved stereo balance. However, when set to P2 or P3, the extreme driving may make true stereo imaging less applicable.
All potentiometers except the bias control are indented for simple recall of previous settings. Using external meter readings is recommended to accurately recall the bias control position.
When just warming the sound, select the T or P1 function and set the output level control to around eight to ten. As you increase the input level or raise the V2 current, reduce the output level control. For P3 applications set the output level control to its maximum.
The cleanest bias setting of the Thermionic Culture The Ultra Vulture is usually 0.22 to 0.32 milliamps with the T function, which adds a subtle sense of naturalness. Consult the test report to verify. To emulate analogue tape distortion, use the T function with normal drive and adjust the meter to between 0.3 and 0.4 milliamps.
A generally popular configuration is the P function with 0.4 milliamps bias and a correspondingly reduced output level. At low drive settings these controls enhance perceived warmth and size of the audio and reduce unwanted transient peaks in a manner similar to a limiter, resulting in a louder perceived output.
On the P2 and P3 functions the valve characteristic can produce a frequency-doubling effect when distortion occurs, owing to waveform rectification; this is most pronounced at bias currents of around 0.1 to 0.2 milliamps. Use the plus ten decibel drive position for extra bite or brightness. With a low bias (that is, higher V2 current) this may provide sufficient gain for some electric guitars when direct injected. Otherwise use the Overdrive setting for guitar direct injection. For extreme distortion you can chain both channels by engaging Overdrive on the first channel. The Filter switch may be used to reduce unpleasant upper harmonics, especially with P2 or P3 settings.
When processing a stereo mix or subgroup, always match the two meter readings rather than relying on identical knob positions. A faithful stereo image is maintained only when the Function switch is set to T or P1. True stereo balance is unlikely in P2 or P3 but this may be desirable for special effects. If you require perfect stereo balance in T or P1 settings you may need to adjust the drive so that the meters read slightly differently; this variation is normal due to component tolerances.
