10 | dac8 Stereo O
wner’s
Manual
| okto research
Driving power amplifiers directly
Low output impedance allows the unit to directly drive inputs of power amplifiers without
the need for a pre-amplifier. In such a setup, the full-scale output voltage of the DAC, which
is 4.2 V RMS in the case of the dac8, and the input sensitivity (voltage required for full power)
of the power amplifier should ideally match to optimally utilize the dynamic range of the
devices. Below are two examples of how the dynamic range can be negatively impacted if
there is a significant difference between the two values:
Scenario 1: Consider a power amplifier with 1 V RMS input sensitivity. The limitation might
occur in the power amplifier if the dac8 Stereo volume is set to -12 dB or higher.
Consequently, the upper 12 dB of the dac8 Stereo's output would remain unused. By
lowering the output voltage of the dac8 Stereo to 1 V, its noise floor could be reduced by
12 dB, preserving the dynamic range.
Scenario 2: Consider a power amplifier with 8 V RMS input sensitivity. In this case, the dac8
Stereo wouldn't be able to utilize the full power of the amplifier, resulting in a loss of 6 dB
in attainable sound pressure level. Elevating the dac8 Stereo 's output voltage to 8 V RMS
would enable it to harness the full power of the amplifier, optimizing the dynamic range of
the setup.
The custom output voltage is available as an optional feature at an additional cost. This
value, determined by a significant number of small surface-mount resistors, cannot be
adjusted by users. The selectable range lies between 1 V RMS and 10 V RMS.
The outputs are protected against long-term short circuit for the default or lower output
voltage. However, we advise against stressing the outputs with a long-term short circuit.
Volume operation
The volume control consists of a master volume (displayed on the right screen) and per-
channel volume, accessible in Menu > Volume. The resulting value for each channel can be
calculated by adding the two values. To bypass the volume control completely, simply set
all the values to 0 dB.
Interfacing with legacy devices with single-ended inputs only
We highly recommend using balanced cabling between analog audio components
whenever possible. The main reason is that, due to the different reference, ground is not a
part of the balanced signal path. This makes equalizing currents created by ground loops