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1. 0dB/Passive and -9dB/Active Inputs and Clip LED
The DynaBlock 400 input circuit has been designed for most basses but all basses have not
been created equally. Some basses have higher signals while others have very low signals.
The power light on the DynaBlock 400 illuminates brighter Red when the input signal
exceeds the amps input range. If the Red power light becomes brighter, lower the volume on
the bass until the illumination ceases.
For optimum clarity, use the 0dB input for bass guitars with standard single-coil pickups or
the -9dB input for active or extremely ‘hot’ pickups such as humbuckers. For an overdriven
edge or “crunch,” use the 0dB input. In either case, the Gain control setting will be a factor in
establishing the type of clean or overdriven sound you prefer.
User Tip: Do not use both inputs at the same time to connect a second bassist or other
musician. The preamp is not designed for more than one instrument to be played at a time.
2. Tuner Jack
Connect your instrument tuner here using a standard shielded (e.g. guitar) cable.
3. Gain Control
The DynaBlock 400 Gain control allows you to set the level of the signal before it’s sent to
the tone controls. This allows control of the tonal ‘sensitivity’ or ‘definition’ of the amplifier.
Higher Gain settings will give more ‘growl’ to your bass.
4. Tone Controls
The four overlapping tone controls cover the entire audio spectrum and permit a wide range
of sonic adjustment. Each tone control has a range of ±15 db. The center position denotes a
neutral or nominal setting. The Bass control adjusts the level of the low frequency; Low Mid,
the next frequency range up). Hi Mid covers a higher frequency range and the Treble control
regulates the upper frequency range.
User Tip: When starting out, it’s a good idea to center all tone controls. Adjust these controls
while playing until you achieve the desired tone. Keep in mind that all tone and EQ circuits are
gain-related, which means it may be necessary to re-adjust the Gain control once the desired
tone is achieved. This will help you to retain the amount of clarity or ‘growl’ you desire.
5. Low Expander Control
The low expander modifies the tone of the bass by reducing the gain throughout the mid
frequencies around 400 Hz while extending the low frequency. By re-shaping the frequency
response in this manner, this provides an expanded tonal palette.
6. Master Volume Control
The Master volume adjusts the overall signal level of the amplifier. Consider it your
“loudness” control.
7. Mute Button
As an aid to tuning your bass silently, the mute function disengages the preamp signal from
all outputs (Line Out, Efx Send, Phones and the amp’s speaker) except the Tuner jack.
When this function is enabled the power light changes color to amber.
8. Power Switch and Lamp
The lamp above the Power switch will illuminate when the unit is on The power lamp serves
three functions, Red for power on, Amber for Mute/standby and pulsating Intense Red indicates
that you are clipping the input and should reduce the gain either on the amp or the Bass guitar.
