Patching together a tube echo

This is my attempt at patching together a tube echo device, using a Line 6 Echo Park (for the delay), a Thermionics Culture Vulture (tube/valve distortion), a Mutronics Mutator (lowpass filter), a Tapco mixer, and a Neutrik patchbay.

Old school dub producers would create delay feedback loops like this using the send and return busses on their mixers. The Tapco doesn’t have sends and returns, so I improvised by splitting the left and right side of the stereo mixer bus into original and delay lines, and used panning instead of sends to control the amount of echo. The end result is a mono delay with a feedback loop that includes distortion and filter processing, so that as the sound keeps echoing it gets progressively darker (filtered) and warmer/fuzzier (distorted), which gives you the sort of retro feel you get from old tape and tube delay/echo boxes.

The Echo Park actually already has a digital model of this type of effect, but I wanted to see if I could do it better! By doing it this way, I also have a lot more control over the final sound, as I can control the amount of filtering and distortion that happens to each echo. I can also use this same setup and patch in different effects, so that the delays progressively get more phaser or flanger or whatever on them as they echo on and on and on…

Anyway, here’s how it is set up:

The original sound comes in via input 1 on the Tapco in mono. This is the external input to the system.

The left side of the Tapco’s main stereo output goes to the main mixing board, where it’s recorded and/or played over the monitors. This is the external output from the system.

The right side of the Tapco’s main stereo output is connected to the delay feedback loop, which starts with the Echo Park, then continues through the Mutator filter, then through the Culture Vulture valves.

The feedback loop comes back in via input 2 on the Tapco in mono.

A delay effect has two primary parameters: delay amount, and feedback amount. The delay amount determines how loud of an echo you get compared to the original signal. The feedback amount determines how many echo repeats you will get, the more feedback the more times you will hear the echo repeat itself.

With this setup, the amount of delay sent to the loop is controlled by panning the original signal on Tapco input 1. Panning hard left results in the signal going straight out the left main output without any signal reaching the delay loop. As you start panning input 1 towards the middle and right, more signal gets sent to the loop resulting in a louder delay.

The amount of delay feedback is controlled by panning the delay loop signal coming into Tapco input 2. Panning hard left results in no feedback, as the processed signal is only sent out the left main output. As you start panning input 2 towards the middle and right, you get more feedback, too much if you aren’t careful, which can result in distortion at the mixer input.

The gain level of input 2, and the various settings of the processors in the effects loop, will also have an effect on the feedback level.

Within the feedback loop, I have the Echo Park set to do a basic simple digital delay with no feedback. The lowpass filter of the Mutator is set so that it lops off some of the higher parts of the sound, resulting in darker echoes. The Culture Vulture is set so that it warms up the sound a bit, but doesn’t distort. By changing the settings on any of these devices, the feedback loop and the resulting echo effect can get much more complicated and/or chaotic.

Here are some examples of how it sounds:

demo #1: dry unprocessed sound
demo #2: tube echoed
demo #3: lots of feedback
demo #4: heavy feedback and some distortion