Review: Presonus Digimax FS

This week I’m on the lookout for an inexpensive eight-channel preamp, so it was an unexpected bonus when I received the Presonus Digimax FS for review. Presonus has a good deal of experience designing this style of converter/preamp combo by now, which it’s gained through the production of its previous Digimax and Digimax LT devices. The Digimax FS serves up the widest array of features of the lineage but still manages to come in as the least expensive of the entire Digimax range, perhaps due to its Chinese manufacture. The FS also foregoes the usual Presonus brushed aluminium fascia and instead uses plastics on its front panel. The remainder of the unit is plate steel and extruded alloy.

Like its brethren, the FS is a single rackmount unit of 150mm in depth. Unlike previous incarnations, however, the Digimax FS has its Neutrik combo XLR/TRS input connectors arranged across the front panel instead of the rear. I imagine Presonus’ R&D reckoned this offered better access to the input connectors for the majority of its projected user-base, such as people wishing to add a further eight inputs to their Digidesign 001/2, RME, MOTU interface etc. Besides which, Presonus has packed a smorgasbord of I/O into the rear panel leaving no room to mount real-estate-hungry XLR connections anyway.

SCADS OF I/O

So what’s going on out the back, I hear you ponder? Scads of I/O, basically. Eight balanced TRS jacks provide direct analogue outputs from each of the preamps – useful if you’re using the unit in a stand-alone situation to send the mic preamp outputs to a separate recorder. There are eight balanced TRS outputs from the Adat or SMUX-connected outputs, with the final eight TRS jacks configured as insert points for the eight preamps. All up, it’s an incredibly comprehensive complement of I/O and, as previously mentioned, a much larger feature set than any previous Digimax design. Aside from the analogue connections there are Adat and SMUX optical inputs and outputs, so a full complement of eight ins and outs is possible all the way through to 96k (the FS will support 44.1, 48, 88.2 and 96k sample rates). Wordclock in and out is present with a termination button should the FS find itself at the end of the clocking chain – nice one. Power is supplied via an external powerpack.

Of the XLR combo inputs on the front panel, the first two are also capable of receiving high-impedance instrument signals. The remaining six TRS inputs are happy with line level signals. To the left of these are two phantom power buttons. Yes that’s right, only two. Phantom power is switchable for Channels 1-4 and 5-8. This is an occasion where the FS falls short of the older Digimax designs, both of which supported individual phantom power switching. Personally, this limitation irks me, although it may be of no concern to others. If panel space is a premium I’d rather manufacturers used smaller recessed switches accessible via a ball-point pen, than lump the phantom power into groups. Sure, many studios can just leave their phantom power running all the time, but personally I’d prefer to engage it on a mic-by-mic basis, without the added concern of what mics are receiving power that shouldn’t. Regardless, the Digimax’s phantom supply provides the full 48V and ramps up and down slowly when switched on and off to avoid clicks and thumps.