Using the same technology as high-end mixing consoles, the Whirlwind DA-2M is an active 2-channel line distribution amplifier sporting two XLR-1/4" combo inputs with mic/line switches and eight balanced XLR line outputs. With individual trim pots for each output jack and variable input gain on each input channel, the DA-2M offers precision control over distributed signals.
The DA-2M features several switchable functions, including mic/line switching (mic mode provides 48V phantom power), low-cut filters, output-ground switches, and an Audio Shield to Earth switch that separates the earth ground of the power cord from the audio ground. You can also activate the Combine switch, which shifts the unit from a 1x4 distributor to a 2x8 distro amp with the two inputs mono summed and feeding all eight outputs. Each input channel provides a 4-segment headroom meter while the eight outputs each sport a clip LED indicator. The unit also features a headphone output with channel source monitor switching and dedicated volume control. The DA-2M includes a power cord.
The mic preamp is set for a fixed 29 dB of gain when the mic/line switch is in the mic position. A trim control after the preamp adds another 28 dB of gain, and then each output level control adds another 17 dB of gain. Total gain is 74 dBV, allowing one to drive power amplifiers to full power with all microphones.
In a typical mic application, the user would set the input trim controls, so that the 24 dB headroom light is illuminated about 50% of the time. With more compressed line level audio, 12 dB of headroom usually is sufficient.
With the headphone select switch in the channel 1 position, channel 1 will be in both earpieces. With the headphone select switch in the channel 2 position, channel 2 will be in both earpieces. The volume control and the headphone amps are designed, so a wide range of headphones of varying impedances may be used.
- The input connector is a Neutrik XLR-1/4" combo jack. Either connector can be used in mic or line mode.
- When the DA-2M's inputs are in mic mode 48V phantom power will be present on the XLR input connector (not present on the TRS).
- A low-cut filter can be activated on both XLR or TRS inputs with a switch. The low cut uses a steep 24 dB per octave 4-pole filter set at 120 Hz, which will reduce wind noise, stage vibrations etc.
- An earth to audio ground lift is also supplied on the back panel of the DA-2M. This switch separates the earth ground of the power cord (which is always connected to the chassis) from the audio ground.
- This ground can also be used to break audio ground loops, however breaking them with the individual channel ground switches is a better approach.
- When in situations with high radio interference, it is suggested to keep audio ground connected to chassis ground.