It boasts a class-compliant USB 2.0 interface as standard, allowing it to serve as a basic computer audio interface and there's an expansion slot for additional I/O option cards, with a Dante interface available.

On the rear, there are eight XLR input jacks that can accept mic or line-level signals. Each mic preamp has a generous gain range of -6 to 69 dB. The M108 can be used as a purely analogue mic preamp, while outputting through a balanced DB25, 8-channel

output. Alternatively, the signals can be A/D-converted and fed to digital output connectors. The internal A-D converter supports all the familiar base, double and quad sample rates up to 192kHz, and provides AES3-formatted outputs on a second D-sub (also conforming to the AES59 wiring standard). A pair of ADAT lightpipe sockets is also provided, and these deliver all eight channels in duplicate at base

sample rates, reducing to four channels on each using S/MUX2 at double sample rates. Although the 176.4 and 192 kHz rates are not supported over ADAT, they are on the AES3 outputs. 0dBFS equates to +24dBu at the balanced analogue outputs. A pair of BNC sockets cater for word-clock, and the input termination can be switched between 75ohm or a high-impedance (daisy-chain) mode.

The USB 2.0 socket allows direct asynchronous connection to a computer or iOS tablet. In addition to the eight mic preamp outputs, the USB interface can return a stereo monitoring signal for auditioning at the headphone amplifier, and so the unit can serve as a basic, but very high-quality audio interface. To facilitate monitoring when recording through the M108, an optional analogue output card can be installed, providing a pair of TRS balanced outputs. In the absence of this option, audio can be monitored through the front-panel headphone jack.

The stereo output options present several choices of source signals. Either can be fed a post-DAW, USB return from the host computer (though this source can be subject to latency). A low-latency blend of input signals can be created instead, using the M108's integrated mixer, and that can be fed to either or both outputs.

The m108 Control Software application allows for control of up to 12 m108 preamplifiers using the Ethernet control port on the m108. Each preamplifier in the system will have a dedicated control panel for operating the microphone preamplifiers, ADC, and clocking parameters. The control application allows for the creation of channel groups as well as saving and recalling presets. The application runs under Windows (7,8.1,10) and Mac OS (10.11). The m108 has a built-in web browser controller allowing remote control from most web enabled Mac, Windows, iOS and Android devices.

Grace have the market for clean 8 channel preamps with digital conversion included pretty much to themselves: this is not a preamp for adding colour, it is a reference tool that delivers precisely what the mics capture.