In recent years, devices for quickly switching between amplifiers and cabinets have gained popularity among musicians. These switchers are ideal for A/B comparisons and studio work, as rewiring cables between amps can be time-consuming and routing cables for comparison is often impractical. Many musicians who own multiple amplifiers prefer to build a complete routing system for their rig at home or on stage. Drawing on my own experience and conversations with other musicians, I have compiled a list of common issues to be aware of when using an amplifier cabinet switcher. These tips are applicable to all brands and will be helpful in optimizing your setup.
Ground Loop Issues:
Amplifier switching devices based on relays are commonly used to switch between two or more amplifiers while keeping the speaker output ground common. However, despite their isolation of sensitive input ground, some devices still suffer from ground loop hum. Moreover, such systems are unsuitable for bridged mono amplifiers where live “ground” and signal wires are hot. To tackle these issues, all N-audio amplifier switching systems including 8X7 Amp Cabinet Switcher, 4X4 Amp Cabinet Switcher and Two Amps To Cabinet completely isolate the inputs and outputs for true isolation without any chance for ground loop hum or noise.
But even with these advanced switching systems, problems can still arise. Most market devices have numerous 1/4″ sockets on the back placed closely together. Using right-angled jacks can cause the jacks to touch, leading to different grounds connecting and creating ground loops. To avoid hum and high-frequency noise, only use straight guitar jacks that do not touch each other. Also, jacks must not touch the chassis. Additionally, grounding the output of bridged mono amplifiers can damage them. Some examples of bridged mono amplifiers include Kemper amplifiers, Orange Micro Terror series amplifiers, BIAS amps, and most modern Class D amplifiers based on off-the-shelf amplifier modules.
Powering Your Rig:
The Importance of a Dedicated Power Source. For best results, I recommend using a single power strip to power your entire rig. Avoid using the same power source for other appliances such as air conditioners, motors, and heaters, which can cause interference and affect the performance of your equipment.
Proper Cable Selection:
Selecting the correct cables for your rig is crucial. There are two types of cables that you will need: one to connect between the switcher and the amplifier input, and another to connect the amplifier output to the speaker cabinet. It’s important to use quality-shielded guitar cables for the input connection, and dedicated speaker cables for the outputs. Speaker cables are typically unshielded with two thick isolated wires. I recommend using cables with a wire thickness of 2×1.5mm2 or 2×2.5mm2. If you need to run long speaker cables, use 2×2.5mm2 cables. It is good practice to physically separate the two types of cables – shielded guitar cables and power cables, in order to prevent the power cables from inducing voltage in the guitar cables.
First Power On:
I understand the excitement of receiving a new toy and the urge to test it out immediately without reading the manuals. However, it’s crucial to exercise patience and attention when dealing with amplifier switching systems that require many cables. Take the time to double-check where each cable goes and ensure you’re using the correct type of cables. Once you’re confident that everything is correctly connected to the switching system, it’s time for the first power-on test. Here’s how I recommend doing it:
- Set all master volume controls of all amplifiers slightly above zero, where you can still hear the guitar but at a low volume.
- Power on your switcher.
- Power on all amplifiers.
- Select the clean channels for all amplifiers with gain and tone controls as you prefer, or start with all preamp controls at 12 o’clock.
- Enable a cabinet.
- Enable the first amplifier.
Now play some clean chords with your guitar. If you can’t hear your guitar through the speaker cabinet, there might be an issue. Do not increase the master level! Keep in mind that the reduced master level is still enough to hear the guitar. If you encounter any problems, turn off everything and investigate before proceeding.
If you hear the guitar through the first amplifier, switch to the second and play some chords with it. Continue testing all amplifiers with reduced master level until you’re confident that everything is working correctly. Test all cabinets as well. Once you’re satisfied, it’s time to rock on!
Power Off:
I recommend turning off all amplifiers first and then the switching system to prevent any accidental pops.
Plugging or Unplugging Cables:
When your entire set of amplifiers, cabinets, and the switcher is functioning correctly, avoid plugging or unplugging cables on the back. Only perform these tasks when all amplifiers are off and routing is safe.
Summary:
If you own a couple of amplifiers and cabinets and control them with any Amp Cabinet Switcher on the market, I hope these tips help you use your complete guitar amplifier rig smoothly without noise or hum . It’s important to remember that all tube amplifiers can’t work without a load, so always run the entire rig or amplifier with reduced master volume. Even in the absence of a load, running the amplifier at lower output power levels will not harm your equipment.
Niki Hristov