From the PAL800 manual:
- Gain - This knob works like the “Pre-Amp Volume” on the British made most famous amps. Turning this control clockwise you will overdrive the pre-amp section of the pedal, obtaining that rich classic distorted British sound that we all love from the 80s. We recommend dialing the Gain control to about 2 o’clock as a starting point. If you want to get that classic vintage sound from the early British tube amps from the 60s, we recommend dialing the Gain control to about 9 o’clock.
The gain of the PAL800 JCM Emulator is very responsive and dynamic; you can clean up your tone by lowering the volume on the guitar and changing the attack on the strings so experiment with that!!! You will love it!!! We are sure you can make it squeal like the real amps!!!
- Presence - This knob controls the general high frequencies of the pedal after the three band EQ section, you could say that it emulates the presence control on the British amps from the 80s at the powersection. Turning this control clockwise you will add more high frequencies to your signal… We recommend dialing the Presence control to about 1 o’clock for a starting point.
- Volume - This knob is the master volume and final stage. This pedal has a very high output level signal depending on the Gain knob position, so we recommend dialing the Volume control to about 10 o’clock for a starting point.
- Bass - This knob controls the amount of bottom end (low frequencies) in the pre-section of the pedal. We recommend dialing the Bass control at 12 o’clock for a starting point.
- Middle - This knob controls the amount of midrange frequencies in the pre-section of the pedal. It is the most responsive of the three EQ controls, so for tone adjustments start setting this knob before the Bass and Treble controls. We recommend dialing the Middle control to about 1 o’clock for a starting point.
- Treble - This knob controls the amount of Highrange frequencies (brightness) in the EQ section, this knob is very similar to the Presence control but in the pre-section of the pedal. We recommend dialing the Volume control to about 1 o’clock for a starting point.
- Master Tone [internal] - If you open the enclosure you will find a trim-pot identified as a “MASTER TONE”, it comes pre-adjusted from factory, however, depending on your taste you can brighten up (clockwise) or darken down (anti-clockwise) a little the general and final tone on your pedal.