CHANNEL-1
INPUT-1: This combo input is designed for both MIC level (XLR) or Instrument level (¼”) signals. (The XLR input provides phantom power)
VOLUME: Controls the overall volume level of CHANNEL-1.
BASS: Adjusts the amount of cut or boost in the low frequency range.
TREBLE: Adjusts the amount of cut or boost in the high frequency range.
Note: When CHANNEL-1 is not in use, be sure to turn all controls to the minimum level to avoid any unwanted noise being passed through the amplifier.

CHANNEL-2
INPUT-2: Combo Input designed for both MIC level (XLR) and Instrument level (¼”) signals. (The XLR input provides phantom power)
VOLUME: Controls the overall volume of CHANNEL-2.
BASS: Adjusts the amount of cut or boost in the low frequency range.
TREBLE: Adjusts the amount of cut or boost in the high frequency range.
Notch Filter HZ: Sets the frequency of the 18db cut NOTCH FILTER that is used to control resonant feedback.
Notch Filter: ON/OFF - Enables or disables the notch filter control.
Shape: ON/OFF This toggle switch enables or disables the SHAPE control. The shape control is a mid dip control. In the on position the mid frequencies will be cut and the high and low frequencies will be boosted.

MASTER SECTION
Effects Assign: This 3 way toggle switch allows the digital effects to be routed to CH-1, CH-2, or if in the middle position will supply effect for both channels.
Effects LEVEL: Controls the amount of digital effect mixed in to the guitar signal from 0% to 50%.
Effects MODE: This is a rotary encoder, which selects 1 of 16 different digital effects. See Digital Effects Program List.
MASTER VOLUME: Adjusts the overall loudness of the amplifier.
Pilot Light/Limit Indicator : When GREEN, this LED indicates that the power is turned on. If the power amplifier reaches full power output, the on board Limiter will be enabled and this LED will turn RED. The Limiter allows the amplifier to be played at full power without unwanted distortion.

DS4 Back Panel
EFX F.S. (FOOTSWITCH): This jack is for connection to a shorting footswitch. When the switch is closed the on board digital EFX will be bypassed.
EFX SEND: This jack provides an unbalanced output from the CHANNEL-2 preamp, it does not include effects or tone control signal.
EFX RETURN: This jack provides a signal pre-eq. It automatically disconnects the CHANNEL-2 preamp when used.
LINE OUT: This jack provides an unbalanced out put from the preamp that is post eq and post efx. This send can be used to feed a signal to a recording or sound reinforcement mixer. Additionally this output can be used to drive a slave amp such as the ULTRASOUND AG-50E.
DIRECT OUT: Balanced output signal, post eq and post efx, used to feed recording or sound reinforcement equipment.
TAPE/CD: Unbalanced phono (RCA) input jacks. This is an auxiliary input designed for use with a drum machine, tape player, CD player, etc. and can be used for playing prerecorded music.
TAPE/CD LEVEL: This “inset” control adjusts the volume level of the TAPE/CD input. This control can be adjusted with a small screwdriver. This signal is pre MASTER control which means that the MASTER volume setting will affect the loudness of the TAPE/CD input signal.