Thermionic Culture THE CULTURE VULTURE Stereo Valve enhancer User Manual
Page 5
© Thermionic Culture Ltd, October 2005
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Controls & Meters
The ‘drive’ and ‘output level’ controls simply vary the amount of
gain that the input and output signals are subjected to.
An output level control setting of around 8-9 will give the
cleanest output for +4dB. Reduce it for lower output levels or
when increasing the drive level for higher distortion.
The ‘distortion’ switch changes the valve from triode ‘T’ (even
harmonics) to pentode ‘P1’ (odd harmonics). ‘T’ is cleanest but
‘P1’ is most popular and will simulate analogue tape distortion at
about 0.4mA current reading. ‘P2’ is an unusual version of
pentode and will give more drastic distortion at high bias
settings, especially when ‘overdrive’ is selected. It will also give
a frequency doubling effect at certain settings.
The ‘overdrive’ switch set near the ‘drive’ control increases gain
current by approximately 20dB, and bias.
The ‘filter’ is a low pass filter operating at 5 or 9 kHz.
The ‘bypass’ switch links the input to output directly, cutting out
the electronics of The Culture Vulture.
The meter reads the current flowing through the 6AS6 valve and
the bias control adjusts this current. Current setting for lowest
distortion is at 0.25-0.3mA.
For a fuller explanation see section 3.