TwinStomp's Active A/B-Y pedal is designed to offer the gigging guitar player an affordable option for driving two amps independently or simultaneously. Built-in is a clean boost control giving an extra 4db separately, or up to 6db when driving both amps.
A blend control enables you to shift the signal mix from Amp A to Amp B, finding the sweet spot between the two. Output B is provided through an isolation transformer to ensure the guitar isn't double-earthed and mains hum is minimal. And for an optional £10 extra, a 180˚ out-of-phase feature can be added to Output B.
The right-hand A/B switch simply switches between amps, the left-hand A/B-Y selects both amps simultaneously – indicated by a dimmed LED. Along with guitar in and two amp outs, we get a 9V power supply input. There's also an on/off switch and a unique 'ring pull' battery compartment for swift access.
With your two rigs set up, simply plug your guitar into the pedal input, then run a lead from both amps inputs into the pedal's A and B output sockets. The first thing we noticed was how quiet the pedal is: the switching is noiseless, which is great for studio and live work.
Even when we cranked the boost control, it didn't muster half as much hiss as expected. How it sounds is down to your specific rig. Tonally it did add a little presence to our two 65 Amps, but the boost is true and clean, really helping to add sparkle to the sound.