Orobas II is a dual tube amplifier that is composed of two identical units.

Each channel has two audio inputs with dedicated gain controls and one output volume control.
Thanks to clever routing, a wide variety of sounds can be created. The two channels can be connected in parallel or in series (Parallel / Series). In series connection, the output of channel 1 is still active, good for parallel signals (note: each channel output is phase-inverted in relation to the opposite input). This way, feedback can be generated by feeding back the signal from output 1 to e.g. a control voltage input.

The screen control voltage input determines the gain and the sound characteristics. Additionally, the input is normalized to INPUT 1 of the respective channel.

The Suppress control voltage input is normalized to the input signal if nothing is connected. The purpose of this input is to direct electrons reflected from the anode back to the anode. Turning the knob to the positive does not change as much, turning it to the negative slightly attenuates overtones. With a positive control voltage the change is minimal, but with a negative control voltage you can realize e.g. ducking effects and effectively switch off the tube. Audio Rate Modulation is also possible here and a bit milder than with the Screen CV, but still effective.

The evocation potentiometer controls the feedback of the second output into the first channel. The sonic performance is very much dependent on the Plate Bias switch. The Plate Bias switch effectively controls the headroom. This allows you to use the tubes in three different settings, from fuzz sound to full distortion.

*This version is equipped with other tubes than in version 1.