Tuner Socket (7 Band); Pre Shape Switch; Valve Switch (12 Band); Drive Rotary Control (12 Band) - TRACE ELLIOT AH1200-12 Owner's Manual

If an active bass is being used with the HI / LO switch set to LO and the INPUT GAIN control is turned
fully clockwise without the red LED lighting at all, then switch to HI and follow the same procedure. This is
because not all active basses have high enough outputs to require the LO setting to be used.
While making adjustments to the rest of the controls keep an eye on the level indication LEDs. Some extreme
settings of the graphic equalizer will increase the signal level into clip. If this happens simply readjust the
INPUT GAIN control as mentioned above.

(5) TUNER socket (7 Band)

This is an output for connecting to a tuner. It is a buffered version of the input signal. Simply connect a 1/4"
jack lead from this to a tuner and you will be able to tune up easily at any time without degradation to the tone.
The signal from this socket is present all at times regardless of any other settings including MUTE.

(6) PRE SHAPE switch

This activates the circuit for the classic Trace Elliot 'Mid Pre-Shape' that all users of previous Trace Elliot
graphic style amplifiers will recognise immediately. As it is our 'signature sound', these amplifiers are designed
to default to this setting when initially turned on. When this is activated the yellow LED is lit.
The actual effect of this circuit is to boost the low and high frequencies (55Hz and 2kHz to 5kHz respectively)
and to cut the mid frequencies (centred around 400Hz), giving an instant, clearly defined, punchy sound. It
can be switched on and off using the front panel switch and also from the footcontroller. Both have a yellow
LED to show its status.

(7) VALVE switch (12 Band)

This switches the VALVE circuit on or off.

(8) DRIVE rotary control (12 Band)

This sets the signal level that is sent into the VALVE circuit.

(9) BLEND rotary control (12 Band)

This controls the mix between the normal sound and the sound from the valve.
The VALVE section uses both halves of an ECC83/12AX7 thermionic valve and is configured to be in parallel
with the normal signal.
Low settings of the DRIVE control will remain basically clean but with valve warmth added due to the
harmonics generated by the valve. Higher settings will drive the valve harder and will result in overdrive
sounds being created.
The BLEND control can then be used to literally blend together the two parallel signals to achieve the desired
effect. With the BLEND control fully anti-clockwise only the normal signal will be present; turning clockwise
will reduce the normal signal and increase the valve sound until, with the control fully clockwise, only the
valve sound is present. This means that in all positions, other than maximum and minimum, the sound of the
valve is blended together with the normal, clean signal which prevents the bottom end losing definition.
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