Radial Engineering BIG SHOT ABY rev2

Radial Engineering's BigShot ABY is a True-bypass ABY switch that allows switching without disturbance or interruption between two different amplifiers. It has a built-in transformer, Ground Lift controls for elimination of hum, parasitic noise and 180° phase inversion; the audio path is entirely True Bypass that is, it does not change the timbre of the instrument. Big Shot is a passive device that requires no power supply.

BigShot ABY True-Bypass Switcher Key Features

• True-bypass ABY selector switch for amplifiers with LED indicators
• Integrated transformer to eliminate hum and noise
• 180° phase polarity reversal to match amplifier phases
• 100% passive audio path, requires no power supply

Radial BigShot ABY compact true-bypass switcher is entirely passive: instrument timbre is not affected by any buffer placed between guitar and amplifier. BigShot ABY also features a separate 'always on' tuner output that sends your guitar signal to a tuner for constant monitoring, keeping it out of the signal chain. In case of hum and noise problems caused by ground loops, BigShot ABY helps you with a built-in isolation transformer switch and ground-lift switch. Once plugged in, you can reverse the polarity of the second amplifier to ensure that both amplifiers sound in phase. BigShot ABY is simple to use and effective on stage. When powered by an external 9V power supply or pedalboard power-brick, the super-bright LEDs come to life providing you with an instant readout of the amplifier's status on stage. When power is not available, the passive audio signal path still works. The compact and extremely robust design makes BigShot ABY ideal for highly articulated pedalboards.

Structure of BigShot ABY

Following the structure from left to right, one notices the instrument input and Tuner output. The Tuner output is always active and allows you to monitor the instrument and make adjustments as needed. The Toggle switch that sends the signal to OUT-A at the bottom or OUT-B at the top. The two amplifiers are connected to these outputs. With the TOGGLE switch you can choose between amplifier A or B, where one could be adjusted for rhythm and the other for solos. In either case, the audio signal is 100% true-bypass-there is no preamp or buffer in the circuit between your guitar and the amp. The BOTH switch combines the paths of the two signals by activating both amps. The OUT-B output also has an isolation transformer switch and a ground-lift switch to eliminate ground loops, as well as a 180° polarity reversal switch that allows you to adjust the phase of the two amps.

Connections

Before making connections, make sure all levels are at zero to eliminate connection transients that could damage the speakers. Make sure that all three switches on BigShot ABY are set down (off), that is, with the transformer excluded from the signal path and ground connected for both amplifiers, assuming the amplifiers are in phase with each other. Connect the guitar to the input, output OUT-A to amplifier A and output OUT-B to amplifier B. Turn up the volume of amplifier A to a low listening level. Start playing the guitar, if it does not come out press switch AB.

Using two amplifiers at the same time

Using two amplifiers at the same time can introduce noise usually caused by different voltages between the two amplifiers, to solve these problems, BigShot ABY is equipped with two switches: The first is the LIFT, which placed upward turns off the ground on the OUT-B output. This eliminates ground loops and noise. BigShot ABY also has a second switch called ISO, which placed upward activates an isolation transformer in the circuit, disconnecting the electrical signal path eliminating hum and noise caused by ground loops.

Playing with two amplifiers in phase

The other advantage of having a transformer is the ability to reverse the electrical phase or polarity of the second amplifier. Often, when using two amplifiers, they may not be in phase. To solve this problem, simply activate the transformer by placing the switch upward and activating the switch 180°, upward the polarity is reversed.

BigShot ABY Applications

Combination of two amplifiers and a Tuner

The BigShot ABY simplifies switching between two amplifiers. With the built-in isolation transformer, hum and buzz caused by ground returns can be eliminated. The dedicated tuner output keeps this device outside the main signal path.

Using BigShot ABY to mute the amplifier

It is poossible to use BigShot ABY as a simple mute footswitch for silent tuning on stage. Just press the AB switch and the signal sent to the amplifier will be muted. This keeps the signal sent to the tuner output active at all times, allowing this operation to be performed without disturbing others.

Using ABY to change the channel of an amplifier

BigShot ABY can also be used to change the channel on older vintage amplifiers that do not have remote switching. They are simply sent OUT-A and OUT-B to the two channels of your amplifier and are selected as needed.