Each of the outputs can be directly switched, allowing you to layer any combination of amps simultaneously. It can also be configured as an A/B/C/D box for selecting between up to four amplifiers with a single button press.

The Amp Selector features a buffered tuner or split output for slaving additional devices without loading down your pickups or muddying your tone. A second input can be used for a stereo signal path, or to switch two instruments into different pairs of amplifiers. The switching is absolutely silent with no clicks or pops.

Level controls for each output provide a convenient way to balance the volume between amps. There is also second input which if used will split the Amp Selector into two separate A/B/Both functions. This is great for applications using two guitars (electric and acoustic, for example) or a stereo signal path. And we included a tuner out‚ which gives you an additional output without loading down your guitar’s tone. Of course you can use this output to run a tuner, but it can also drive a direct signal to a console or even chain additional Amp Selectors if you need more than four amps.


The Voodoo Lab Amp Selectors inputs drive a pair of ultra transparent buffer amplifiers. These amplifiers input characteristics have been carefully matched to that of a traditional vacuum tube guitar amp. This insures that your guitar pickups will see the correct load and therefore sound their best. Using a buffer amplifier is what allows us to drive multiple amplifiers and a tuner without excessively loading your guitar and destroying your tone. Each amplifier output is coupled using a high quality shielded and sealed transformer. Isolating each output with a transformer is what breaks the ground paths between amplifiers. Without this, current would flow through ground loops causing your amps to hum. In addition, we have developed a proprietary matching technique to drive the transformers. By carefully matching impedances and component values we are able to greatly improve the performance of the transformer. The result is a true, super accurate sound without any loss of tight low-end response.

The Tuner output provides a copy of whatever goes into Input-A. This is a non-isolated slave output for a variety of purposes. It is always active regardless of amp switching status. Typical uses would be to drive a tuner, direct out for recording, or to chain additional Amp Selectors.

Individual level controls allow you to conveniently balance volumes of each amp. Normal position is about 3 o clock. At maximum they will provide a very small amount of boost. Any significant volume changes should be done with the level controls on your amp itself. In normal operation, the amp select buttons simply toggle each amp output on and off. Check out the Operation section of this manual for programmable switching options.

Connections - Connect the output of your guitar into Input-A of the Amp Selector. If you are using pedal effects in front of the amplifier, then connect from the output of your last pedal into Input-A of the Amp Selector. Connect Amp Outs 1, 2, 3 and 4 to the inputs of each of your amplifiers. Initially, set each of the Amp Selector’s Ground Lift switches to the ON‚ position. If you are going to use two guitars (or the other channel of stereo effects) simultaneously with different amps, you can connect the 2nd guitar into Amp Selector Input-B. If you do this, the Input-A instrument will only access amps 1 and 2, and the Input-B instrument will only access amps 3 and 4.

Power - The Amp Selector can be powered either by its internal 9V battery or an external power source. The battery compartment is on the bottom of the unit. Use a Phillips head screwdriver to remove the single screw holding the battery cover in place. The external power jack requires a regulated 9VDC power source. The connector polarity must be center negative. The best choice to power your Amp Selector would be with a Voodoo Lab Pedal Power. It will also work fine with other 9VDC regulated adapters such as the Boss PSA.
Powering the Amp Selector on and off is done via the input jack, just like most pedal effects. Insert a cable into Input-A to power on. Remove it to turn the power off. If you are powering the Amp Selector with a battery, always remember to disconnect the Input-A cable to preserve battery life.

Operation On/Off Mode - The default switching method of the Amp Selector is what we call on/off mode. In on/off mode, each of the four buttons 1 through 4 simply toggle the corresponding amp output on and off. Using on/ off mode is a good choice if you want maximum flexibility to switch or layer amps.

Exclusive Mode - Unlike on/off mode, which requires two button presses to switch between amps (one to turn the old amp off, then a second to turn the new amp on), Exclusive mode lets you change amps instantly with a single button press. Each output can be individually configured for on/off or exclusive mode. By setting only one of the 4 outs to exclusive, Amp Selector will operate in what we call single exclusive. If you set 2 or more outs to exclusive, those outs form an exclusive group.

Single Exclusive - If one of your amps is always played alone (basically never layered with others), you should use single exclusive. You can select the on/off amps in any combination, but selecting the exclusive amp turns all others off. Likewise, selecting any on/off amp while the exclusive amp is selected will turn it off. Following the instructions below under PROGRAM, set only this amp’s out to exclusive and the remaining 3 outs to on/off.

Exclusive Group - If you have 2 or more amps that are never layered with each other, you can make them an exclusive group. Now when you select a new amp within the exclusive group, the old amp is automatically turned off. Any amp set to on/off can still be manually selected and layered with the amp in the exclusive group. Following the instructions below under PROGRAM, set each of these outs to exclusive and any remaining out(s) to on/off.

Program - To enter the Amp Selector’s programming mode, do the following:
1. Power off the unit by unplugging the cable in Input-A.
2. Press and hold button 1 while powering on by inserting the cable into Input-A.
3. All LEDs will flash to indicate you’re now in programming mode. Now you can select on/off or exclusive mode independently for each output. Pressing each button will toggle the mode:
LED Off = On/off mode
LED On = Exclusive mode
To exit programming mode and return to normal operation, simply power the Amp Selector off by removing the cable in Input-A. TIP: For a complete list of the most common setups and how to program them, check out www.voodoolab.com/ampselector.htm!

Ground Problems - You should always start with all of the Amp Selector’s Grounds Lift switches in the ON position. This means the output is grounded. If the amp is humming, the first place to look is if there is a two or three position ground switch on the amplifier itself. Try each position of the amp’s ground switch to find the least hum. If the amp continues to hum, then try switching the Amp Selector Ground Lift to the OFF position. This now isolates that output. Then try each position on the amp’s ground switch again to find the least hum. If you are still having problems, make sure that all amplifiers are powered from the same power source. Outlets in different parts of a room can have significantly different ground potentials making it more difficult to find settings that are hum free. Since ground connections in a multi-amp setup can get complicated, you may need to experiment a bit with different combinations of settings to find one which keeps all the amps from humming.