Radial SGI: Send Your Guitar 300 Feet With Zero Tone Loss

The Radial SGI is the Studio Guitar Interface, a two-box line driver system that carries an unbalanced instrument signal as far as 300 feet (100 meters) over a standard XLR microphone cable without hum, hiss, or loss of tone. The SGI-TX transmitter takes your guitar or bass, buffers it, and balances it for the long run, while the SGI-RX receiver catches that signal at the far end and converts it back to instrument level for your amp. For any player who has ever fought noise on a long cable run, it is the box that finally lets the amp live in another room while the tone stays exactly where you left it.

Why a Long Guitar Cable Kills Your Tone

An electric guitar puts out a weak, high-impedance signal, and a long unbalanced cable treats that signal badly. Every extra foot of cable adds capacitance that drains high frequencies and dulls the tone, while the cable itself becomes an antenna for lighting buzz, dimmer hum, and radio interference. Past 20 or 25 feet the sound goes soft and the noise floor climbs, which is why running a guitar straight across a big stage or between studio rooms rarely works. The only real fix is to lower the signal's impedance and balance it before it travels, and that is exactly the job the SGI was built to do.

How the TX and RX Work Together

The SGI splits the work across two boxes joined by one cable. Plug your guitar into the SGI-TX and its discrete buffered circuit drives the signal out balanced over a standard XLR microphone cable, the same rugged, inexpensive, road-ready cable already stocked in every venue and studio. At the far end the SGI-RX receives that balanced feed and converts it back to a proper high-impedance instrument signal, so the amplifier sees exactly what it would if the guitar were plugged straight into its face. Run one mic cable between the two boxes and the amp can sit up to 300 feet away.

Jensen Transformers Keep the Signal Pure

The heart of each box is a premium Jensen JT-11-YPMC transformer, one in the TX and one in the RX. These transformers do two jobs at once: they isolate the two ends to break the ground loops that cause hum and buzz, and they form part of the conversion circuit itself. Their industry-respected windings deliver a wide, flat 10 Hz to 40 kHz response, very low noise and distortion, and an enormous 121 dB dynamic range, so the signal coming out of the RX is a faithful copy of the guitar that went into the TX rather than a distant, degraded echo of it.

Drag Control Restores Your Pickup's Natural Feel

Electric guitar pickups are sensitive to whatever they are plugged into, and the wrong load can make them sound harsh or lifeless. The SGI-TX includes Radial's Drag Control, a variable load adjustment from 22k to 422k ohms that lets you dial in the exact resistance your pickups want to see. It is the same interaction that makes a guitar sound right plugged straight into a tube amp, now available at the front of a 300-foot signal chain. A ground lift switch is on hand as well to clear up any remaining hum from a troublesome power connection.

Pedalboard-Friendly Power and Real-World Uses

The current SGI ships with a 15V power supply for the TX, but it also runs on any standard 9V to 15V pedalboard supply, center-positive or center-negative, so it drops onto a board without a dedicated brick. In the studio it lets a guitarist sit in the control room and hear the mix while the amp roars in an iso room down the hall. On stage it feeds off-stage isolation cabinets, links wireless systems to pedalboards, and pairs with the Radial JX44 V2 to place a full rig up to 300 feet away. The RX is passive and needs no power of its own.

Who the SGI Is For

The SGI is for the recording guitarist who wants the amp in another room but the performance in the control chair, for the touring player fighting cable noise on a big stage, and for anyone building a complex signal path who needs to move guitar between wireless, pedalboard, and amplifier without losing a hair of tone. Set the amp wherever it sounds best and let the SGI carry the signal to it quietly, faithfully, and as far as the room requires.