DI boxes might not solicit the most excitement as a prospective Eurorack investment, but in an ecosystem that is by now as much about holistic electronic production as it is about synthesis in the purest sense, it has never been more important to make sure that what’s coming out is worthy of the work you’re putting in. Extracting the best possible signal out of a modular system can sometimes be rather a headache, with ground‑related issues, analogue noise floors and the rest. That’s also before you get to the obvious fact that modular level is incredibly hot, more often than not precluding the meaningful use of any preamps on the way into the box and consequently limiting the scope of their relationship with the rest of your outboard gear.
Enter Runic Labs, a new developer from Glasgow whose debut design is the aptly‑named Passive DI. Needless to say, to open proceedings with such a fundamental utility is a bold move, but as a devoted user of such units as the Golden Master Pedal from Endorphin.es and a proponent of the ‘high‑pressure audio’, I can say with some certainty that when a design comes along to add that extra something to your end‑of‑chain signal, it’s well worth paying attention.
There are, in fact, surprisingly few Eurorack designs in this category worth writing home about. The closest thing to the Runic Labs design is probably the also‑transformer‑based XFMR Euro DI Output Module from Turkish developer Vaemi; beyond this are a handful of other variations on the theme, but I daresay Runic Labs are here offering something rather pure; a genuinely no‑compromise DI that stands tall next to anything by the likes of Radial, Telefunken or Rupert Neve Designs. We’re told that this particular module began life as a regular DI box taped into a Eurorack performance case, with custom panels designed to bring the I/O into a patch‑friendly format; Runic Labs even sent me the original breakout panels with my review units to illustrate the story.
Carnhill Transformer
Indeed, based around a weighty, British‑made Carnhill OEP mu‑metal shielded transformer, it’s clear from the outset that this is nothing less than a piece of high‑end studio gear in modular form. To my ear the transformers in question are as detailed and subtly warm as you could want them to be for such a multi‑faceted purpose as funnelling a Eurorack system, and the addition of 10dB and 20dB pads (plus the option for the two to work together as a 30dB pad) also gave my studio’s mic preamps an opportunity to flex with some nice harmonic saturation. As is often the case with these things, it’s difficult to quantify the impact of every stage of the signal chain down to a granular level without truly forensic testing, but listening to, for instance, a single saw wave hitting my DAW at exactly the same peak level both with and without the Passive DIs in the chain, there was a noticeable enough difference in signal smoothness and harmonic content.
Runic have paid good attention to ensuring these can work well in pairs and just as well in fours, with high‑precision metal‑film resistors promising negligible signal variance of 0.1%. Although they’re just 6HP apiece (though with faceplates happily offering four screw holes to keep things secure when plugging in hefty XLR cables), mounting four of these in your system, a total of 24HP, might start to feel like quite a concession on rack space; but to this end I might recommend something along the lines of an unpowered 4MS pod (being passive, of course, they don’t need any power), rendering the Runic PDs a very smart — and compact — standalone DI rack. After all, impressively, each is just 36mm deep.
Runic Labs’ debut DI is a robust, quality piece of gear that will unequivocally improve the sound of your system.
With a ground‑lift switch and, usefully, a jack for thru completing the picture (as someone who routinely sends signals to amps and into the console concurrently, this was welcome), Runic Labs’ debut DI is a robust, quality piece of gear that will unequivocally improve the sound of your system. Fair to say the price is, for a DI box, considerable. But — to play the devil on your shoulder — once plumbed in, would you ever regret it?