User Manual

Stack Section 140
 Clarity
“Clarity” changes the sound of the distortion in a new and unique way. Turning the “Clarity” soft knob to the right will
bring the clean character of the sound into focus without lowering the amount of distortion. The distortion itself will
become less forward in the mid frequencies and sound far more transparent.
 Tube Shape
“Tube Shape” controls the distortion characteristics of the tubes, ranging from very soft to very hard. All kinds of
crunch sounds can be dialed up - from warm blues, to singing metallic, to harsh. Depending on the gain setting or
the playing style, the resulting effect can be rather subtle; completely distorted sounds are mostly unaffected by this
parameter, as are clean sounds. Set the value to 3 to simulate the typical sound of preamp tubes. To achieve a
power amp tube character, try setting “Tube Shape” to around 9. Power amp tubes produce a much harder
distortion, because the negative feedback in the power amp circuit linearizes the tube amplification, making the
distortion curve edgier.
 Tube Bias
“Tube Bias” influences the overtone structure of the distortion. While the effect on the character of the sound is fairly
subtle, you should feel a quite a difference in the distortion dynamics: as you increase the amount of “Tube Bias” the
guitar will go into distortion much earlier in the dynamic range, yet still retain a lot of dynamic headroom. At
maximum value, the distortion characteristics mimic those of a Tube Screamer™.
 Direct Mix
With “Direct Mix” you can open up a parallel path to the amplifier distortion and mix a clean portion of the guitar to
the distorted sound. This will add some dynamics and attack to the sound, as well as adding some of the frequency
content of the clean guitar. Traditionally, similar results were achieved by running the guitar through a clean and a
distorted amplifier in parallel (“dual amping”) - now, it can be done with a twist of a knob. “Direct Mix” controls the
volume of the clean portion.