The MSDI sits between head and cabinet and sends a speaker-simulated signal to wherever you want.
MSDI is an acronym for Microphone Simulated Direct Interface. Simply connect your amp’s speaker output to the Input From Amplifier socket on the MSDI, connect your speaker to the Speaker/Load socket and take an XLR cable to your mixing desk or preamp. The DI signal has been shaped to simulate a mic’d up cabinet, and this means you can send your guitar and amp signal to a PA engineer, or even record without needing to use a mic. The MSDI employs passive circuitry, so there’s no need for a power supply or a battery.
Since the MSDI’s output reflects the volume setting of your amplifier, an onboard Output Level control helps tweak the level to stop your preamp overloading. A three-way tone switch offers a Reference setting as well as Hi Cut and Hi Boost, and there’s even a GND (ground lift) switch to eliminate 50Hz hum from earth loops.
We tested using a Fender Princeton and found no amplifier/speaker colouration whatsoever with the MSDI in line. We then recorded through the MSDI to compare the DI signal with the sound of the speaker and it sounded just like a well-mic’d studio amp, although a touch of spring reverb helped take away the dryness. No doubt, the MSDI gives a remarkably ‘natural’ tone.
Devices of this sort are often a bit disappointing, but the MSDI surprised us. Regardless of whether the amp was set whisper-quiet or flat-out, the MSDI remained distortion-free and we had no interfacing problems whatsoever.