This Article Was Originally Published On: July 1st, 2014 #Issue 14.
A great name piques your interest and sometimes hints at things to come. The name “Sonic Farm” certainly does both. Thought of in their best light, farms are wholesome; they are natural; they grow the things we need to survive. Translated into the amplified/recorded (“sonic”) world, preamps and direct boxes are certainly things we need, and we definitely want them to be wholesome and natural. So far, so good. While something has to be extremely good “to die for,” even in the non-literal sense, Sonic Farm has turned this slang phrase into a formal noun. This play on words (well, play on letters and numbers, really) has multiple levels. At the heart of its name, the 2di4 is a DI, so that works. It’s also two DI’s in one (a pentode tube DI, and a triode tube DI). And, without spoiling the ending, it is extremely good. I’m still working on the “4” part, though…
Farmers Unite
Sonic Farm Pro Audio is the brainchild of two men whose friendship spans not only decades, but continents, as well. Zoran Todorovic and Boris Drazic met back in 1966, in the former Yugoslavia, when the two musicians formed a band and started gigging the Adriatic coast. Both studied electrical engineering, graduated, and got steady jobs. The two started their own recording studio in the early ’80s, and experienced a good bit of success. However, the conflicts in their homeland led them to seek their fates elsewhere in the early ’90s. Boris went to Germany, then on to Canada. Zoran ended up in a recording studio in Los Angeles, and stayed there for 15 years. In 2009, however, the two joined forces in Vancouver, British Columbia, and formed Sonic Farm Pro Audio.
Any field of manufacturing has its celebrated icons, and the audio recording world is no exception. Neve and API are hallowed names, and with good reason. They set the standard for studio preamps, and have lead to many boutique builders offering clones, or slightly tweaked versions of their circuits. This is a world which Sonic Farm seeks to steer clear from. They believe that focusing on yesterday’s designs limits tomorrow’s possibilities. One of their founding premises is to come up with pro audio equipment that the world market is not already saturated with. Furthermore, they attach no mythical benefits to any one type of technology or design. To that end, they don’t care if their products use tubes, transistors, op amps, or IC’s, so long as it gets the tone they are after.
With that background in mind, let’s see what happened when they decided to make a DI…
What’s a DI, Anyway?
We use them all the time, but do you really know exactly what a DI does? Or what those letters stand for? Well, it’s the box the sound guy makes you plug into when you ask him to mic your rig, and he says, “No, use this,” right? Sort of, but there’s more to it. Whether you call it “direct input,” “direct interface,” or “direct injection,” a DI connects a high-impedance, line-level, unbalanced output signal to a low-impedance, mic-level, balanced input. The most typical scenario where we bass players see a DI used is to send the signal coming out of our bass into a mixing console, either live, or in the recording studio. Our rigs are designed to accept the signal right out of our instrument, but those pesky mixing boards are not. Still, it seems like a simple task, right?
Your DI is actually doing more than you might think. It is matching levels, balancing the signal, eliminating ground loops and minimizing noise and distortion (either through active buffering or passive impedance matching). Especially in a live setting, you are typically playing your bass a goodly distance from the mixing board, so the DI needs to send your signal a long way, without losing anything along the way. And it’s doing all of this while sitting between YOUR bass, and YOUR rig, so it darned well better not get in the way or screw up the mojo you’ve been dialing in for years.
In its most basic form, the typical DI box has a 1/4″ input (from your bass), a 1/4″ output (to be sent on to your rig), and an XLR mic-level output (to be sent to the mixing console). Hopefully, there’s a ground lift option, as well. These devices may be found in either passive or active form (hint: if it has a power cord or takes a battery, it’s an active DI).
Features To Die For
The 2di4 covers all the DI basic function, but offers some very nice “value added” features. Let’s familiarize ourselves with the front and back panels a bit. Up front, we of course have the requisite 1/4″ input (labeled “In”) and 1/4″ output (labeled “Amp”). But check out all this other stuff! The big white knob controls the final output level, and it’s a straightforward affair, but the rest deserve a little explaining. The two white push buttons are labeled “Gain” and “T/P.” The Gain button provides a signal boost of either 5dB or 9dB, depending on the setting of the next button. The T/P button allows you to run the EF86 tube (which is the heart and soul of the 2di4) in either triode mode or pentode mode (the technical aspects of this are discussed in detail in Tom Lees’ Amp Lab portion of the review). The bottom row of controls also features a bi-color LED which glows green when a signal is present, and red when the input signal begins to clip (though this is more of a “rough estimate” indicator of clipping; more on this, below). The LED set between the Gain and T/P buttons glows blue when the unit is powered up. The two small holes above the Trim label are actually level (gain) controls for the Lo and Hi Boost functions.
Moving up to the top row of controls on the front panel, we find three mini-toggle switches. The first one has settings for 0 (no gain reduction), -12dB and M (which mutes the signal after the tube stage and before the output buffer). Since the 2di4 does make a very audible “pop!” when switching between triode and pentode mode, I would strongly suggest that you engage the mute before hitting that T/P switch. Note: the -12dB attenuation setting occurs post tube and preamp output stages, so instead of being there to knock down the level of a hot input, its intended use is for adjusting the output to avoid overloading a low-headroom device, such as a computer interface/AD converter. Next up, we have the two 3-way switches for Lo Boost and Hi Boost. In the middle position, no boost is applied. Options 1 and 2 provide fixed boosts to the lower frequencies or higher frequencies. These are gentle shelving controls, and so they impact a fairly wide range of frequencies. For the specifics on what frequencies are affected by each switch, I once again refer you to the Amp Lab portion of the review.
Turning our gaze to the back panel, we find two XLR outputs; one labeled “D.I. Out,” the other “Line Out.” The D.I. Out is your more traditional output, and it delivers a balanced, mic-level output via a very nice Cinemag transformer (which also protects the device from accidentally engaged phantom power). The Line Out is also balanced, but this time via op-amps, and it delivers a significantly hotter, line-level signal. Sonic Farm lists the max gain on the Line Out as +54dB, versus +32dB via the transformer-balanced D.I. Out. Other back-panel details include a ground lift switch, on/off switch, 300mA fuse, IEC power cord socket, and Mains Voltage switch for 110v or 220v operation. Clearly, Sonic Farm has covered all the bases, and then some.
Harvesting Sonic Crops
As previously indicated, there are several ways that you will likely use a DI, and you want your unit to excel at all of them. What most people will hear (whether it’s at a live performance or via a recording) is what’s coming out of the balanced outputs. Most sound engineers will likely use the D.I. Out, but in some situations, the hotter signal from the Line Out may be the ticket. Fortunately, they are simultaneously available. Both outputs deliver a faithful reproduction of the input signal, but with a most pleasing blend of organic warmth and detail. Listening to the two of them (after gain matching), the signal from the D.I. Out sounds ever so slightly more full and “girthy.” Credit likely lies with the sweet Cinemag transformer. However, the Line Out is no slouch in the fullness department. It’s just that D.I. Out nudges ever so slightly ahead in back-to-back comparison.
The EQ options available from the Lo and Hi Boost switches are not likely to replace a full tone stack (if you need one), but are good at making very musical nudges in one direction or another. Powerful EQ can offer a wide range of tone sculpting, but EQ can do very bad things, as well, and I have always found too much EQ to be much harder to deal with (either in a live mix or in the studio) than little or no EQ. The gentle slopes chosen by Sonic Farm and the use of capacitors and inductors mean that the 2di4’s boosts won’t muck up your tone. I found them to be very useful, and a very welcome feature. It is worth noting that the Lo and Hi Boost are only available when the Gain switch is not engaged. This is a result of the design of the tube gain stages, where you have the option of either a global frequency boost (hitting the Gain button) or more tailored Lo and/or Hi boosts, but not both at the same time. Zoran Todorovic explains, “The unit provides more than enough gain for any bass guitar on the market. The idea behind the Gain switch was to drive the tube harder, when desired.”
The variety of gain control options are very nice, and this will allow a wide range of instruments to effectively interface with the 2di4. Since this is a tube-based device, it also means that you have the ability to dial in varying levels of tube saturation. Not all tube-based DI’s allow you to intentionally push the input signal into clipping, but the 2di4 happily does so. Personally, I am not likely to seek a saturated tube overdrive from a DI box, but if you want to put just a bit of “hair” on your signal, Sonic Farm has you covered. The tube saturation in triode mode is probably a bit more familiar-sounding for bass or guitar, but check out what pentode mode has to offer, as it does have a somewhat different character. Of course, if you like to keep things clear and pure, have no fear. The 2di4 has a very wide range of tones/gain available before you are anywhere near clipping. On that topic, though, I must point out that the front panel indicator LED is not your best tool for determining when you might be hitting tube saturation. As always, use your ears.
“Ah, but Tom, what about this brick getting in the way of your stage rig; your pride and joy?” Well, the Amp output is a direct copy of the input, albeit a buffered copy. At first blush, it seems completely identical to the input signal, but after a little A/Bing, you can notice the effects of the buffering – which is not necessarily a bad thing. Using a passive Carvin PB5, the buffered signal was just a touch more full and meaty. Switching to an active Skjold Exotic Custom 4, the low end was identical between the direct signal from the Skjold and the Amp output, but the high end coming out of the Amp output had and extra layer of detail that was quite nice. In short, I’ve got no problem running the 2di4 in between my bass and rig. In fact, I dig it a lot!
Direct Comparisons
Although their “job” seems very simple and direct (excuse the pun), your DI will, to a greater or lesser extent, impart its on sonic signature on your bass tone as it gets sent on up to the FOH or recording studio board. With the 2di4, at the very first listen, it strikes you as an exact copy of the signal from instrument. However, more careful listening shows the 2di4 to be organically warm, clear and detailed, and somewhat more harmonically rich than the input signal. That it can do all this without changing the natural character of the individual instrument is impressive. In this regard, it reminds me of another favorite tube DI, the Demeter VTDB-2b Tube Direct. Comparing the two of them back to back, the 2di4 is a tad more warm/round, and the Demeter is a tad more articulate/detailed, but the two were very close – which, again, is an impressive feat, considering the VTDB-2b’s pedigree.
Just for kicks, I also compared the 2di4 to a very plain-Jane, pedestrian DI, the passive Groove Tubes Direct Box (model PDI). While the PDI is an entirely competent device, there is an immediately audible difference which is best summarized by the responses to each: “Eh,” versus, “Wow!” Feature sets aside (the GT’s features start, and end, with the ground lift switch), the 2di4 has more life and dynamics.
The Bottom Line
If you are a gigging bassist or a studio musician, you need a DI. The DI’s job seems simple, but it’s very important that it doesn’t screw it up. Yes, you can get the job done with a fairly inexpensive piece of kit, and to be honest, if you’re just getting your feet wet as a bassist, or if you routinely play to less than discerning crowds, perhaps you’re just as well off with a more modest box. However, if you really care about that recording; if you need to nail that live tone; if you want to be sure that your Fodera sounds like a Fodera, both at your rig and at the board, then a high quality DI is your best friend. There are some very nice options out there, but few – if any – can match the build quality, feature set, and sonic excellence embodied in Sonic Farm’s 2di4.
In-hand
| Features: | 4 |
| Tonal Flexibility: | 4 |
| Ease of Use: | 4.5 |
| Aesthetics: | 4 |
| Tone: | 5 |
| Value: | 3.5 |
In-hand Score 4.17average
TONE-O-METER:
The 2di4 is faithful to your instrument’s voice and character, but adds a touch of warmth and harmonic excitement, while keeping things clear and controlled. In addition, it offers multiple ways to subtly, yet meaningfully, tweak your signal (gain and tone).
