The tuner output can be a very useful feature that expands the functionality of your guitar rig. The current and upgraded N-audio 4X4 and 8X7 Amp Cabinet Switcher include several improvements in this area, making the tuner output more flexible and reliable in real-world rack and studio setups. In this post, I’ll explain how the tuner output works, why it is active only in mute mode, how it can also be used for DAW recording or amp modellers, and how to solve possible high-pitched noise issues with some rack tuners.
How the Tuner Output Works
The main goal of every N-audio amp switcher is simple: keep the tone intact. Even a small amount of extra circuitry or additional load can slightly affect the sensitive guitar signal, and nobody wants that. This is why the signal path between the guitar and the amplifiers uses only relays. The tuner output works only when the amp switcher is in mute mode. This keeps the guitar signal completely isolated from the tuner while you are playing, which helps preserve the pure relay-only signal path. It also lets you tune silently, just like you would with a pedalboard tuner.
If you prefer your tuner to stay active all the time, the solution is simple: plug your guitar into the tuner first, then connect the tuner output to the amp switcher input. In that setup, the tuner remains active all the time and also works as a buffer before the amp switcher.
Using the Tuner Output for DAW Recording and Amp Modellers
The amp switcher is usually used to switch between real amplifiers and speaker cabinets, but the tuner output can be used for more than just tuning. When the amp switcher is in mute, the guitar signal can be sent directly from the tuner output to a DAW input, audio interface, amp modeller, or recording device. This can be especially useful in a studio setup. For example, if you use a modern amp modeller such as a Neural Quad Cortex, you can connect it to the tuner output and easily compare your real amplifiers with modelled or simulated tones without unplugging cables or changing your rig.
Chris Holland from CDH Guitars, who has extensive experience with guitar recording setups, made an excellent review demonstrating this exact use of the N-audio 8X7 Amp Cabinet Switcher:
The High-Pitched Noise Issue with Some Rack Tuners
Over the years, rack tuners have been designed in different ways. Some older models used proper 3-pin mains power connections, others were powered by transformer-based external adapters, while many newer units use modern switch-mode power supplies with no ground connection.
The problem with some switch-mode adapters is that their output can remain floating and may carry high-frequency switching noise. In many rack systems, this is not a problem. Once the tuner is connected to grounded equipment, such as an amplifier, the noise disappears. However, when a rack tuner is used with an amp switcher, the tuner ground can remain floating while the tuner output is not active. In some cases, this can allow high-pitched noise to leak into the guitar signal through capacitive coupling inside the amp switcher. One of our clients, Dirk Baranowski from GittarSchool in Germany, experienced this issue when using a modern Korg rackmount tuner with his 4X4 amp switcher. To solve this, the hardware of the 4X4 and 8X7 amp switchers was upgraded with a ground lift switch placed next to the tuner output.
Recommended Ground Lift Switch Position
The recommended position for the tuner ground lift switch is LIFT. This is also the best setting if you want to use the tuner output to connect an amp modeller, DAW input, audio interface or other recording device. If you use a rack tuner that creates high-pitched noise, switch the tuner ground lift to GND. This connects the tuner ground to the amp switcher signal ground and eliminates the floating-ground noise issue.
Simple Workaround for Older 4X4 and 8X7 Units
If you have an older 4X4 or 8X7 amp switcher without the tuner ground lift switch, there is still a simple solution. Plug a short patch cable between the rear tuner output and the Slave input on your switcher. This pulls the noisy tuner ground down to the switcher’s internal signal ground and eliminates the noise. The Slave input is automatically disabled when the front-panel input is used, so this grounding trick does not interfere with normal operation.
Niki Hristov