Props to Sonar for this info:

FRONT PANEL (left to right)

1) INPUT HI – High sensitivity input (also has a brighter tone).
2) INPUT LOW – Low sensitivity input (also has a slightly darker tone).
3) LEAD EDGE – Frequency dependent gain boost; gain increases as you play up
the neck (it’s subtle).
4) LEAD GAIN – Amount of Overdrive.
5) LEAD – Activates Lead Gain, Volume and Edge. Overrides Rhythm and Clean
channels. Must be OFF for Rhythm and Clean channel to operate. *
6) LEAD VOLUME – Pre FX loop
7) RHYTHM BOOST – Switches from low gain (clean to slightly dirty) to medium
gain (crunch to medium overdrive) **
RHYTHM GAIN – Activated by Rhythm (9)
9) RHYTHM – Toggles between Rhythm and Clean channel.
10) RHYTHM VOLUME – Activated by Rhythm (9) pre FX loop. *
11) RHYTHM EDGE – Same function as Lead Edge for Rhythm channel.
12) TREBLE – Active for both Rhythm and Lead channels.
13) SHIFT – Active for both Rhythm and Lead channels. Shifts Treble, Middle and
Bass shelving down.
14) MIDDLE – Active for both Rhythm and Lead channels.
15) BASS – Active for both Rhythm and Lead channels.
16) CLEAN VOLUME – Gain and volume for Clean channel, pre FX loop.
For initial set-up, set to approximately 2 o’clock with
Master Volume at approximately 2 o’clock and match
Rhythm Volume and Lead Volume to desired setting.
17) CLEAN BOOST – Gain Boost for Clean channel. **
19) BRIGHT – High frequency boost (becomes less active as Volume increases.
21) SHIFT – Low midrange boost between Middle and Bass frequencies.
22) BASS
23) GRAPHIC EQUALIZER – PreFX loop (+/- 12 dB).
24) MASTER VOLUME – Power amp volume control (post FX loop)
25) STANDBY – 11 = Full power
0 = Standby
1 = Half power (two tubes)
26) MAINS – Lovely emerald green, don’t you think?

* Front panel button must be OUT for footswitch to operate.
** Front panel button must be IN for footswitch to operate.

REAR PANEL (right to left)

1) PRESENCE – Active, all three channels.
2) EFFECTS SEND – Send level set by preamp volumes.
3) EFFECTS LEVEL – Sets overall send and return level (-10,0dB).
4) EFFECTS IN/OUT – Also activated by footswitch jack (see EQ).
5) EFFECTS RETURN – Overall level adjusted by Hi/Low switch, then feeds to
Master Volume.
6) EQ IN/OUT – Button must be out for footswitch to operate.
LINE OUT (Jack) – Power amp line out.
9) LINE LEVEL – Power amp line level.
10) SPEAKER OUTPUT – “Use First” jack must be plugged in for output to operate
11) IMPEDANCE SELECT – 4, 8, 16 ohm (speaker jacks wires in parallel).
12) MODE - PENTODE: Full power. Full range power amp response.
TRIODE: Four tube, half power. Softer highs and lows.
Vintage amp response.
13) POWER AMP MUTE – Deactivates power amp while leaving preamp active.
FX SEND serves as preamp out in this mode.

Reverb footswitch jack is located on the bottom right side of the amplifier chassis, directly behind the reverb connectors.

NOTE: When switching to HALF POWER mode (standby switch in position “1”)
impedance selector value should also be divided by two.
EXAMPLE: Impedance setting “8” for 16-ohm speaker.
Impedance setting “4” for 8-ohm speaker.
This will help extend tube life and maintain low end punch.