KHE + Boss Waza Tube Amp Expander

This guide explains to how to use the Boss Waza Tube Amp Expander (TAE) in combination with the KHE Amp / Cab Switcher. Make sure to read this guide and all product manuals in great detail before hooking things up. If incorrectly connected or used, the equipment may be damaged. Better be safe than sorry!

Table Of Contents:

• Overview

• Wiring & Setup

• Basic KHE + Waza TAE Operation

• Safety Notes

• Boss TAE FX-Loop Operation

• Using the TAE FX-Loop in 4-CM

• Troubleshooting & FAQ

Overview

The Boss Waza TAE is an active-type attenuator: Instead of using a simple passive attenuation pad like most traditional attenuators, it uses a reactive load box in combination with a 100W Class-AB solid-state power amp (mono). Between the load box section and the power amp section, it has a line-level fx-loop, which enables to use effect pedals post-amp, even if the amp doesn't have a real fx-loop.

The Boss TAE is best connected to the ACS Attenuator Insert Loop. All functions of the TAE can be used as normal with the KHE amp switcher:

• Use the TAE as a global power attenuator with all amps and speaker cabs (or power booster).

• Use the TAE fx-loop to share effect pedals like Delay, Reverb, EQ with all amps (post-amp loop).

• Use it as a load box in for silent recording.

• Use it as a power amp for preamps and modelers.

• Use the line out with an audio interface for recording with IR processing.

The KHE and the Boss Waza TAE are a perfect match (we love our TAE)!

Wiring & Setup

The Boss Waza TAE is best connected to the ACS Attenuator Insert Loop. This is a serial insert point between the amp outputs and the speaker cabs. By default, the KHE’s Attenuator Insert Loop is deactivated. If not activated, the attenuator won’t work correctly.

Important: Before connecting the TAE to the KHE, make sure the KHE and all amps and cabs are all working correctly. It’s crucial to be methodical during the setup. Start with the most basic KHE setup possible (only amps+cabs, no pedalboard or attenuator) and add things step by step. Same for the TAE fx-loop: Get the basic TAE/KHE setup running first, and only add the fx-loop if things are working correctly.

1. Connect the red TAE - FROM TUBE AMP jack to the white KHE S-LINE SEND, using a speaker cable. This sends the activated amp speaker output signal to the input of the TAE’s reactive load box.

2. Connect the black TAE - TO SPEAKER jack to the white KHE S-LINE RETURN, using a speaker cable. This sends the attenuated amp signal from the TAE back into the KHE cabinet switching section. The two speaker output jacks are connected in parallel and have the same signal, so it doesn’t matter which one you use. For the Impedance Switch settings, see all details further down below.

3. Power-On the KHE. Do not power-on the amps or TAE yet. Turn the master volume of the TAE and amps down.

4. Activate the KHE Attenuator Loop in the System Menu after connecting it. If not activated, the attenuator won’t work correctly. See this link: How to activate the KHE Attenuator Insert Loop

5. Power-On the TAE and the Amp Heads and let them warm-up for 2 minutes .

6. Activate an Amp+Cab on the KHE and slowly increase the volume of the amp and the TAE and test everything in detail.

7. The system is now ready to use.

Impedance Setting

The TAE is a combination of a reactive load box and a solid-state power amp. Thus, it isolates the the tube amps from the speaker outputs so to speak. Set the TAE’s IMPEDANCE knob to match the impedance of the amplifier outputs (i.e. 8 Ohm amps = Ohm on the TAE). The TAE’s speaker output jacks is an universal output that works with 4, 8 and 16 Ohm speaker cabs (no setting required). Don’t go below 4 Ohm total load. Set the TAE Input Level switch to match the most powerful amp in your rig. This is a line-level signal switch to adjust and optimize the internal headroom. Learn more about impedance and impedance mismatch in the KHE Impedance Guide.

Ground Lift Switch

The Boss TAE has several ground lift switches. In case of hum or high-pitched noise issues, experiment with the ground lift switch setting. See the section below for more troubleshooting information.

Alternative Wiring Variants:

• Single Cab or Load Box: If the TAE is only used with a single cab, or as a load box with its internal load and no speaker attached, connect it to a red KHE CABINET jack. For the KHE ACS 4x2, this wiring is the only connection variant.

• KHE ASX / CSX: Connect the red ASX CAB MAIN to the red TAE Amp Input. Connect the PS Speaker Output to the CSX Speaker Input. Use speaker cables. See more information in the ASX CSX user manual.
  

Basic KHE + Boss TAE Operation

Attenuator Operation

To use the TAE as an attenuator, set the TAE power switch to ON and make sure to have the KHE Attenuator Loop activated. Use the TAE SPEAKER VOLUME knob to set the master output volume of the rig. Use the KHE’s amp and cab switches to freely choose any amp or cab at the push of a switch (no need to stop playing, the KHE takes care of the switching and muting). Always have the TAE powered on.

Silent Operation (Load Box)

For Silent Operation with the TAE in the KHE’s Attenuator Insert Loop, simply set the TAE SPEAKER OUT VOLUME to 0 so it operates silently. The TAE must be powered on all the times. A cabinet output must still be activated on the KHE, but it won’t receive any signal with the speaker volume turned all the way down. Alternatively, if the TAE is exclusively used as a load box with no speaker cabs at all, it is best connected to the KHE’s Cabinet Switching Outputs (red CAB jacks)

Attenuator Bypass

The TAE does not have a attenuator bypass switch and the KHE itself can also not bypass the attenuator. Deactivating the KHE Attenuator Loop does not bypass the the attenuator. Learn more: ACS Attenuator Insert Loop

Device Position in the Room

In some situations, being close to the attenuator or load box with the guitar can result in a high-pitched squealing noise. This happens due to the high magnetic field generated by the inductors and transformers of the attenuator or load box, causing feedback with the guitar pickups. Try physically separating them and avoid standing too close to the device with your guitar. You can find additional information in this Video by Fryette Amplification and in this Blog Post by Two Notes Audio on the topic. Make sure to provide proper cooling airflow for the attenuator or load box.

Notes

• Effects, Line Out, Amp & Foot CTL, USB & Headphones: All these knobs, features and functions can be used as normal.

• When daisy-chaining MIDI devices with the TAE’s MIDI IN / OUT, set the OUT/THRU jack to THRU configuration in the TAE software by USB. By default it is set to OUT, which causes it not to pass incoming messages to the MIDI output.

• According to some forum discussions, it’s recommended to only use the LO setting of the RESONANCE-Z knob as an additional safety measure when playing the amps at high volumes (unconfirmed, not KHE-related).
  
  

Safety Information

Always activate the KHE Attenuator Insert Loop

The Attenuator Loop is deactivated by default. If deactivated the attenuator won’t work correctly. Always activate the Attenuator Loop in the KHE System Menu. The KHE can not bypass the attenuator.

Cabling Safety

Make sure to wire and connect the system correctly. Always power-off all amps and attenuators during cabling changes. Use quality cables and make sure the plugs are fully inserted into the jacks. Do not leave the rig unattended. If you leave the room, set all amps AC power switch to standby! Better be safe than sorry. Learn more: ACS Cable Guide

Load + Switching Power Rating

The Boss Waza TAE reactive load box is rated for 150W RMS. The KHE has a maximum power switching rating of 150W. Learn more: KHE Maximum Amp Power Rating

Transistor & Solid-State Amps

According to the Boss Waza TAE User Manual and FAQ, it is only compatible with tube amplifiers. It is not compatible with solid-state (transistor) amps. Using such amps with the TAE can cause damage on the amps or the TAE. The KHE by ifself works fine and safe with solid-state amps.

Power-On Sequence

All amps + KHE + TAE power off> KHE power on > TAE power on > Amp Heads on with standby for 2 minutes > KHE activate AMP > Ready to rock!

Power-Off Sequence

Deactivate KHE Amp+Cab > Amps power off > TAE power off > KHE power off > Good Night!

Boss TAE FX-Loop Operation

The TAE’s fx-loop can be used as a master-fx-loop for all amps. It enables to easily share post-amp effects like Delay, Reverb, EQ or Noise Gate with all connected amps by only two cables. It is a serial mono fx-loop for line- or instrument level and operates post-amp, after the preamp/overdrive section, similar to a traditional amp fx-loop. The TAE fx-loop can be bypassed by the TAE front panel button or via MIDI.

FX-Loop Wiring

1. Connect the TAE FX-SEND to the input of the pedal board by a shielded instrument cable (TS).

2. Connect the TAE FX-RETURN to the output of the pedal board by a shielded instrument cable.

3. Set the TAE Loop Switch to SERIES. Set the TAE level switch to +4 for line-level effects or to -10 for instrument-level effects. Set the ground lift switches all to NOR to start with. In case of hum problems (ground loop) experiment with the ground lift switches and check which setting gives the best results.

4. Press the TAE FX-LOOP Button to activate or bypass the loop.

5. Connect any pedals such as Overdrive or Boosts in front of the KHE guitar input.

Pedal Board Power

Use isolated DC power for each pedal section. Do not use daisy-chain adapter cables between the pre- and post section. Keep the grounds of each section isolated all the time. If using a single PSU with multiple DC outputs, make sure the outputs are 100% isolated. Many cheap PSUs are not or have grouped outputs. Otherwise a ground loop may happen (hum & squealing noise). Also experiment with the Ground Lift switches and check which setting gives the best results. See the section below for troubleshooting tips.

KHE FX-Loop vs TAE FX-Loop

One common question is whether to use the KHE fx-loop switching or the TAE fx-loop. The answer is simple: It depends.

• If you plan to always use the TAE as an attenuator and like how it sounds, there's no reason not to use its fx-loop. It only needs two cables, making it easy to use. It even adds an fx-loop to amps that don't have one. It’s very convenient.

• On the other hand, if you only want the TAE for the fx-loop and don't really need the attenuator function, I suggest the KHE fx-loop switching instead. A load box + power amp will always slightly change the sound compared to the true amp + cab interaction. Not necessarily better or worse, but different. For the most authentic amp sound, use the real amp fx-loop with the KHE fx-loop switching (without any attenuator at all).

Using the TAE FX-Loop in 4-CM

4-Cable Method with the TAE FX-Loop

It is possible to use the TAEfx-loop in 4-CM, for example with multi-effects units, Noise Gates or with pedal switching systems. Also it is possible to use modern amp modelers as a 4-CM effects units, such as the Neural DSP Quad Cortex, Fractal Axe Fx, Boss GT-1000 or similar. Used like this, the device will only work as a effects processor (usually no amp- or cab modelling). With these devices, a clean grounding is crucial. Sometimes these devices can create a ground loop which requires to be solved with a signal isolation box (with transformer).

Noise Gates in the FX-Loop

When using a noise gate with key input, such as the Fortin Zuul, you may have to use a quality signal splitter with transformer isolation for the key input source. Keep the grounds of each section isolated all the time. Otherwise a ground loop may happen (hum & squealing noise).

Troubleshooting & FAQ

No sound at all / Attenuator isn’t working correctly

• Check if the Attenuator Loop is activated in the KHE System Menu.
  Maybe it got deactivated because it not connected during power-up (safety feature)?

• Make sure an amp + cab is activated on the KHE

• Double check wiring, it’s easy to mix things up.

• Make sure cables are fully inserted & functional.

• Downsize system to only amps+cabs with no attenuator or pedals.

• Make sure the devices are being operated correctly.

Hum Noise or High-Pitched Squealing Feedback Noise

• Is the KHE Attenuator Loop activated? Double-check everything above.

• Check if the Ground Lift & FX-Loop Level switch has any positive effect.

• Dynamic Noise: Does the noise change your position in the room? Does it get worse if you move closer to the attenuator or load box? If the noise disappears when turning the guitar volume down, then the noise is most-likely caused by magnetic interference with the (reactive) load device and the guitar pickups. You are standing too close to the device. Move your guitar around to learn how it reacts. Try moving the attenuator or load box a little further away or lower gain and volume as a last resort.

• Static Noise: If the noise is still present, even with the guitar volume turned all the way down and not changing with your position in the room, the noise is most-likely caused by a ground loop somewhere. First, check the TAE fx-loop and the pedals. Make sure to use isolated 9V power for the fx-loop to avoid ground loop. Don’t use daisy-chain power adapter cables. Temporary remove the pedals to isolate the problem. If using a noise gate with key input such as the Fortin Zuul, use a splitter with transformer isolation for the key input to avoid ground loop. Keep the pre- and post pedal section ground isolated all the time. Experiment with the TAE and KHE Ground Lift Switch setting. Make sure to have an amp activated on the KHE.

Sound or noise coming from inside amp/attenuator/load box

• Sound of broken speaker inside the amp: When an amp or load box is pushed hard, it can cause weird noise and sound which kinda sounds like a small broken speaker, coming from inside of the amp or transformers. Fear not! This is normal. The vibrations from the transformer laminations and inductors can create strange distorted sounds, but there's nothing to worry about.

• High-pitched squeal coming from inside the amp: Immediately power everything off (TAE, KHE, Amps) and verify the correct wiring of the amp. Make sure the cables are fully inserted and in good working shape.

Can I use fx-loop without attenuator or in bypass?

Nope, it’s not possible to use the fx-loop in standalone. It is part of the full system: Load Box > FX-Loop > Poweramp

Learn more: KHE Troubleshooting Guide and ACS Attenuator Loop Guide

Links:

• Official Boss Waza Tube Amp Expander Website

• Boss Waza TAE User Manual

• Boss Waza TAE FAQ & Troubleshooting

• KHE Rig Rundown with Boss TAE on Facebook

Return Home: KHE ACS Help Center

Disclaimer: All product names, trademarks, and logos used in this guide belong to their respective owners. This guide is purely informational and does not suggest endorsement, sponsorship, or affiliation with the mentioned companies. While great efforts have been made to ensure accuracy, actual compatibility of our product with third-party products may vary, and we do not guarantee their performance or functionality. ALWAYS READ AND STUDY THE USER MANUALS OF THE INVOLVED PRODUCTS. Users are advised to thoroughly test and validate any combinations, and we disclaim responsibility for any issues that may arise. If you have any feedback to help improving this guide, please let us know.