The switch is shown on the website specification layout of the tubes. It is on the Armageddon also. There is no label on the amp itself but it has a label on the web spec. It is not mentioned in the owners manual either?? Anyone ?? Bueller? Bueller??
There is definitely a subtle difference between the two positions.
I think I like the ODS position better for tight grinding rhythms and I may have preferred the ODV for more lead oriented riffs.
What is the switch doing?
The V setting is for the tube input into the OD channel. S is a very cool, high voltage MOSFET/FET input circuit that, as you found, closely duplicates the sound of the tube. The S circuit does this without the inherent noise and microphonic issues that plague tubes in high gain amps.
The V setting is for the tube input into the OD channel. S is a very cool, high voltage MOSFET/FET input circuit that, as you found, closely duplicates the sound of the tube. The S circuit does this without the inherent noise and microphonic issues that plague tubes in high gain amps.