This is by far the best A/B/Y switcher we have ever used.
Built in Germany, Palmer is the choice of touring musicians all over the world. The unit includes the power supply, and the dip switches on the back allow for extensive polarity adjustments. In other words, normally 2 amps or a stereo rig will give you all kinds of noise, but this feature allows you to strip all that noise from your system. All switching is silent and "popless"
These units sell new for $475, and are impossible to find used!
From Palmer's Website:
The Triline basically routes guitar signals to different amplifiers and functions as an active A/B/Y box. The Triline's universal design makes it possible to utilize various options:
1. A single guitar can be routed to either amplifier A or B or to both.
2. Two guitars can be routed to different systems, e.g. an electric guitar to a guitar amplifier, and an acoustic-electric guitar to a PA system via an integral DI box.
3. A dedicated output is provided to connect a tuner. The Triline can be muted for silent tuning.
4. Using an additional device (E-Frog), one guitar can switch between two amplifier heads. However, both amplifiers use only one speaker cabinet, i.e. the output of the amplifier in use is routed to the speaker cabinet. A load box prevents damage to the amplifier which is not in use.
The routing is done without any audible delay or clicking noise. The outputs to the amplifiers are tranformer isolated to prevent ground loops and humming. You can match the channel gain using the trim potentiometers. There is a special output for connecting up a tuning device. During tuning, the amplifier outputs can be muted.
• Inputs: 2 x 1/4” jack A/B (guitar or other instrument)
• Outputs: 2 x 1/4” jack (floating ground). Channel B with additional balanced XLR/m for connection to mixing console mic input. Can be muted for tuning
• Output tuner: 1 x 1/4” jack, “Control” output for E-Frog (1/4” jack). External power adaptor with 4 pin screw on connector
• 3 foot switches: Channel A, Channel A + B, Channel B
• 3 Dip switches for ground lift