In recent years we’ve seen a major surge in the introduction of bass preamps and DIs, as seemingly every company in the space has been racing to release their own version. This checks out — now that technology has largely antiquated heavy rigs and oversize cabinets, there’s high demand for portable amp solutions that gigging bassists can pack on the fly for travel and frequent shows. I’ve tested a wide array of these boxes, and each one has unique features and characteristics that distinguish it from its contemporaries. Always looking to explore the latest, I was excited to get my hands on the R2D3 Helion preamp from Sunnaudio. 

Having already produced a number of great pedals that cater to us bass players (including the Nucleus Dual Boost Distortion, Stage Prestine preamp, and Rabbithead Analog Preamp Overdrive), Sunnaudio was sure to engineer the Helion with the needs of us low-enders in mind. The company consists of a small team of musicians in Belmont, California, who are meticulous about their creations and focus on every detail of their work — so when they explained that the R2D3 Helion is the culmination of all of their previous preamps put into one package, I had to see what this thing could do. 

Customizable To The Core

Upon unboxing it, the first thing I noticed was how small and lightweight the Helion is compared to other preamps. At 4.75″ x 3.75″ x 1.75″ (less than half the size of most other preamp/DIs), it can comfortably fit on any pedalboard or slide into the pocket of any gig bag. The next noticeable trait is the number of knobs. A large Drive knob is fixed in the center next to the Volume knob, which lights up with a brilliant-green LED when you activate the pedal. A Tone knob shapes the overdrive, a Rabid knob and activation button propels the pre-drive boost circuit beyond overdrive into fuzz territory, and the Focus knob and activation button injects sub-harmonic frequencies back into the drive circuit. In terms of controllable options, this thing really overachieves with the EQ: not only Bass, Mid, and Treble parametric EQ, but also EQ frequency controls (60Hz–300Hz, 0.8kHz–3kHz, and 3kHz–12kHz). An XLR Out switch gives you the option for all EQ, no EQ, or Bypass, and two switches allow you to bypass and mute or activate the drive with a quick toe tap. The back of the box also includes four DIP switches: Input Impedance, Tone Range, Bass EQ Shape, and Treble EQ Shape. That may seem like a lot to unpack, but it’s more intuitive than it sounds and makes the box extremely fun to play around with. 

The Whole Sonic Spectrum

I plugged in a Fender Precision Bass, running the output of the Helion into an Ampeg SVT and 210 cabinet. To figure out the preamp’s capabilities, I started by setting all of the knobs to 12 o’clock. I scooped the mids with the Parametric EQ and increased Drive to about 3 o’clock after activating it. Even at this subtle setting, the clarity and articulation of the notes became crystal clear, and the entire rig sounded like a whole different setup. The body of the low end was deep but cut through, even at the bottom of the neck. Playing with the parametric EQ and EQ frequency controls alone could take up a whole afternoon, which I most definitely did. The frequency options became more pronounced when I switched to an active Music Man bass, which produced some seriously heavy mids and pronounced highs.

Of course, with any new pedal we want to test its extremes, so I took the Drive knob up a few notches and activated the Rabid pre-drive boost circuit, dialing in the knob at about 4 o’clock. This gave the bass a gritty-yet-clear tone that made me reach for a 5-string to test the limits at this setting. A Moollon J bass’ B string reacted beautifully and sang from the first fret to the 20th. Dialing back Drive yielded a highly pronounced sound that led me to readjust the EQs in all manners of configurations — after all, this thing has no shortage of knobs, and we’re going to twist them.

This propelled me into the territory of the Focus knob, which ultimately adjusts the overall balance between lows and highs. Turning it counterclockwise increased the bass and made some wall-shaking happen, particularly between the 5th and 9th frets on the B string. Pulling back the EQ’s highs and mids, and rolling on the Tone knob, dialed in a supreme dub sound that would make the late, great “Familyman” Barrett smile (may he rest in peace). This function alone would make this preamp valuable, but its response in the mid and high territories is what solidifies its well-roundedness. With a pick and the EQ heavy on mids and highs, and Drive at 3 o’clock and Rabid activated, you achieve a legitimate rock and punk tone that cuts impressively. With a scooped EQ and Drive rolled back, the preamp could be left on for an entire set of rock and slap-funk songs. 

Something For Everyone

After spending a few days with the R2D3 Helion, it was hard to find any flaws in its design or execution. The durable box is intuitive and simple to operate, and its sheer number of options makes it a worthwhile purchase for any bass player looking to enhance their overall tone. Its compact size makes it more appealing than other bulkier boxes, and honestly, it’s just a fun thing to sit down with and dial in. In creating a preamp that merges all of their previous innovations into one, Sunnaudio succeeded in raising their own bar with the Helion.

Price $475

Pros More options than most preamps; Focus control is amazing for low-end rumble; parametric EQ is extremely precise; small and lightweight

Cons None

Bottom Line This highly customizable preamp packs tons of tone-sculpting power into a compact design.

For more visit: Sunnaudio