Radial''s X-Amp is an active device that converts line-level signals to instrument level, allowing you to patch an already recorded guitar, bass, or other instrument track back into an amplifier for reamplification.
Reamplification has been around for decades and is a favorite trick of professional engineers, yet it's a technique that's often overlooked in personal studios. Radial's X-Amp ($200) could help to change that. It is a Class-A device that makes it easy to transform line-level signals into the proper impedance and level for input into guitar amplifiers, stompboxes, or other instrument-level devices.
The obvious use of the X-Amp is to run a dry, DI-recorded bass or guitar track from the multitrack back into an amplifier to change or tweak the tone. The advantages are that the player doesn't have to commit to a sound at the time of tracking, and, after he or she is gone, you can spend as much time as you'd like experimenting with different amps, settings, and effects until the desired sound is achieved.
The best way to do that is to run the guitar into a DI box, routing the dry signal direct to your multitrack from the balanced output and sending the instrument level output to an amplifier. Let the guitarist set the amp to taste (distortion, effects, and so on) so that he or she is inspired to play a great part. (It's a good idea to also record the amp at this time.) Played effects such as feedback and false harmonics are recorded into the dry signal and will be reproduced when reamping.
Why the need for the X-Amp? Guitar and bass amplifiers (and stompbox effects) expect to “see” a certain signal level to operate properly. The X-Amp changes the line-level signal of your recorder's output into the proper level and impedance; otherwise, the amp or effects won't sound right or could even be damaged.
The X-Amp's input is balanced, XLR line level. (Be aware that the XLR connector does not “click” into place.) Ground lift switches are provided for both the input and output. An LED lights if the signal going into the X-Amp is too hot.
The X-Amp is active (powered by a 15VDC wall-wart power supply) and can provide two ¼-inch outputs: one direct-coupled and the other transformer-isolated. Two amps can then be driven simultaneously without ground loops or grounding noise. A phase-reverse switch is provided for output 2, and an output-level control lets you to adjust the signal into the amp or effects chain.
X-Amp is not just for reamping dry guitar or bass tracks. The creative-minded person will run vocal tracks through guitar amplifiers and percussion sounds through stompboxes. Many keyboards, synth tracks, and samples benefit greatly from being reamped.
I reamped several guitar parts using the X-Amp and was extremely pleased with the results. In one instance, I recorded the original part using a DI to split the signal coming from the guitar, running one side to a Line 6 Vetta II amplifier while recording the dry signal into my DAW. (I recorded the amp with a dynamic mic at the same time.)
I was playing a heavily distorted sound with moments of controlled feedback throughout. After several passes, I comped the final take together, making identical edits to the recorded-amp and dry-guitar tracks.
I later used the X-Amp to route the dry signal back into the Vetta II. After toying with the output level and the ground switches, I had a signal going into the amp that sounded exactly like I was in the room playing. I experimented with the Vetta II until I settled on a sound I really liked. I also used the second output of the X-Amp to drive a small Vox combo amp set to a clean sound. I then hit record and printed the new guitar tracks.
When I listened to it later in the day, I realized that I'd rolled off too much of the Vetta II's highs. No sweat. I swapped the dynamic mic for a ribbon and recut the tracks using the X-Amp's output to drive the Vetta II, with satisfying results. The flexibility of reamping, and the utility of the X-Amp was abundantly clear. I was sold.
X Marks the Spot
X-Amp flawlessly does what it's supposed to do. The signal it produces is clean, strong, and sounds exactly like the original guitar output. The unit is built like a tank, and you get added versatility from its output control and dual outputs. Most importantly, the sonic options of reamping, which the X-Amp facilitates, are considerable. If you regularly mic guitar amps in your studio, the X-Amp is a no-brainer.