Radial Engineering has made built-to-last solutions that meet everyday studio and live needs for decades, and their new SGI Stereo instrument line driver – designed primarily for guitar and bass – is another excellent example. The SGI Stereo lets you drive two unbalanced, low-level instrument signals up to 300 feet via a CAT5 Ethernet cable without noise or signal loss. It is designed for use on stage or in the studio. Long cable runs fed by instrument pickups (even via stompboxes) can lose clarity and pick up electronic interference; a problem Radial's SGI products help solve. With this new addition, the SGI system now comes in single-channel SGI [Tape Op #99] (via XLR) and SGI Stereo (via CAT5) versions. The SGI Stereo consists of transmitter (TX) and receiver (RX) boxes that each sport a pair of Jensen transformers. The TX has an included 15V power supply but can run on pedalboard power from 9V to 18V. The RX also has a ground lift for both channels and a 180-degree phase inversion button. The TX also has handy 1/4-inch Thru options. The devices have the same form factor as the JDI and JDX48 direct boxes in the Radial line. The claimed frequency response is 20 Hz to 18 kHz +/-1 dB with a very low total harmonic distortion. Connectors are unbalanced 1/4-inch, and the CAT5 jacks are also compatible with locking Neutrik etherCON connectors.
A typical use case scenario would be a path like this: guitar/bass>effects pedals (if used)>SGI Stereo TX>CAT5 cable>SGI Stereo RX>amp(s). Pedals can also go between the RX and the amplifier instead of in front of the whole chain. I used the SGI Stereo in both stereo and mono configurations, and I immediately thought of two scenarios where I could put it to work. The first was running from my pedals in the control room out to an amp in the live room. For the purposes of A/B-ing, I set up runs with and without the SGI. The total run was around 75 feet from my spot in the control room, through and under several doors, to the amps at the far end of the live room. Not close to the 300 feet the SGI Stereo can handle, but still significant enough to make signal degradation a potential issue. The SGI Stereo was the clear favorite of the two options. Even using high-quality guitar cables for the non-SGI path, I found the SGI Stereo to be cleaner, clearer, and noise-free. We quickly ditched the standard run and sent the signal from the RX side of the SGI to both amps instead of using just the left/mono side, and I didn’t notice any loss of tone in doing so.
My other test involved a longer run from my home studio/barn control room, across the driveway, and into the house’s living room. I have always thought about recording guitars in the house, as the room has a nice natural tone, but I have been hesitant due to the length of the cable run. Again, I set up two paths. One used jumpered-together, super long cables that I purchased years ago for my kid’s elementary school play that I was roped into doing sound for (“You’re a sound guy, right?”). That path went into an old ’70s Marshall 2x12 combo. For the other, I connected the two SGI Stereo units using a 100-foot CAT5 cable, patched my guitar into some pedals, and then into the SGI Stereo's TX. I ran the output from the receiver to two amps (a Vox AC30 and a Fender Princeton Reverb) in the living room. The first (non-SGI) path was pretty noisy. It was still somewhat usable, but it had significant hum issues. With the SGI Stereo, the signal was strong, with no crosstalk or extra noise other than the normal crackling of the AC30's faulty tubes. For kicks, I ditched the first path and swapped out the AC30 for the Marshall. It was remarkably cleaner using the SGI Stereo.
Like everything Radial Engineering makes, the SGI Stereo is built like a tank and will be around long after I kick the bucket. The SGI Stereo will interface with many Radial products, but understand that it is not a DI or a re-amping device. As with many of the company’s products, it does a specific job and does it very well!