You have a spring reverb, a tape echo or a good old delay pedal, and you want to run it on your mix. Or you flipped the FX SEND switch from INT to EXT, and nothing happened.
Short answer: the Dub Mixer has four effect sends, one per source (CH 1, CH 2, AUX 1 and AUX 2). Each one goes either to the internal effects unit, or out to your external unit through the FX SEND and FX RTN sockets. The INT/EXT switch does not route anything on its own: it arms a destination, and the FX SEND knob you move next is the one that picks it up.
That detail is what trips most people up the first time. Here is the whole thing in order: the cabling, the assignment procedure, how to dial in the return, and the settings that live in the configurator.
What the Dub Mixer effects loop does
The Dub Mixer carries its own effects engine, and it can also feed an external unit. Both paths share the same mechanics: one effect send per source, and one destination selector.
Four sources have their own FX SEND knob:
- CH 1 and CH 2: the two main channels, whatever source is selected on them.
- AUX 1 and AUX 2: your mics, your instruments, your live sources.
The knob sets how much signal you send to the effect. The destination is chosen with the FX SEND switch, in INT or EXT position.
One source goes to one destination at a time. But each source is independent. You can send your turntable to your external tape echo while the mic plugged into AUX 1 feeds the internal delay. That is the most common way to play dub: the voice in one machine, the music in the other.
The full path, from channel to mix:
CH 1 / CH 2 / AUX 1 / AUX 2 → FX SEND → INT (internal effects) or EXT (FX SEND socket) → external effect → FX RTN → high-pass → mono → gain → main mix
One thing that matters while you play: the send is taken after the volume and after the crossfader. When you close a channel fader, you also cut what feeds the effect.
[IMAGE: overall block diagram of the FX Send / FX Return loop]
The full internal routing, channel by channel, is covered in Inside the Dub Mixer: internal functions and audio routing.
Connecting your external effect
On the back panel you have two dedicated sockets: FX SEND and FX RTN.
Both are 6.35 mm unbalanced stereo jacks. One socket per direction, not one for left and one for right: the left channel sits on the tip, the right on the ring.
Which cable you need depends on your effect unit:
- Your unit has two separate jack sockets: a 6.35 mm stereo jack to dual mono jack cable.
- Your unit is on RCA: a 6.35 mm stereo jack to dual RCA cable.
You do the same the other way round for the return: the outputs of your unit come back into FX RTN. Both cables are in the complete cable pack, along with everything else that plugs around the mixer.
Your effect unit has to run 100 % wet. In a send/return loop the dry sound is already in the mix, it runs through the channel. If your pedal sends dry back on top of the effect, you double it and you get comb filtering. Find the mix or dry/wet control on your unit and push it fully to wet.
If your effect works in mono, or if a mono cable is all you have on hand, switch the send to mono in the configurator. Without that, a mono jack only picks up the left channel.
Sending a source to the internal or the external effect
This is where people get stuck. The FX SEND switch is not a global selector that flips the whole machine. It arms a destination for the next knob you are going to touch.
Two moves and it is done:
- Set the FX SEND switch to INT or EXT.
- Turn the FX SEND knob of the source you want to route.
That source is now assigned to that destination, and it keeps it in memory. The other sources stay where they are.
The catch: if the switch is already on the destination you want, nothing will happen. It has to change position to arm. Flip it to the other position and back (INT to EXT to INT), then turn your knob.
Once you have that down, you spread your sources however you like. A setup that works well live: CH 1 and CH 2 on the external tape echo for the music, AUX 1 on the internal delay for the mic. You play on two different effects all night without ever touching the switch again.
Dialling in and cleaning up the return
The return does not land raw in the mix. It runs through its own processing chain before it reaches the main bus: high-pass filter, then mono option, then gain.
The high-pass filter is the one that changes everything. A delay or a reverb fed with bass sends back a mush that clogs the low end and makes your scoops work for nothing. The filter cuts the low end out of the return and keeps the effect where it belongs, in the mids and the highs.
There is also a high-pass filter on the send side, active by default. That one stops bass from reaching the effect in the first place. It is the answer to the question that comes up most often: why is my bass going into my delay?
The mono option sums the return, handy when your effect works in mono, or when your system is wired in mono.
The gain sets the level of the return before it joins the mix. That is your overall effect amount, while the FX SEND knobs set the amount source by source.
The settings that live in the configurator
Some of the loop settings are not on the front panel. They live in the configurator, the web interface you use to customise your machine. In there you get:
- The default destination of each send. You decide what each source does at startup, so you do not have to reassign everything every time you power up.
- The high-pass filter on the send and its cutoff frequency.
- The mono mode for the send and the return.
- The siren and sampler send to the effects. There is no front panel FX SEND knob for those: their send is an internal setting you make once in the configurator.
Getting started with the configurator is covered in How to configure and customize your Dub Mixer.
The internal effects unit (INT. FX)
When a source is routed to INT, it lands in the INT. FX section on the front panel. Four controls drive the loaded effect: TIME, MOD, VOL and TAP. What each one does depends on the effect in place.
On the delay, TIME gives you the delay time, MOD the modulation depth, VOL the effect volume, and TAP the tempo tapped by hand.
Still on the delay, TAP deserves a word, because it has two modes. LED off, you are in manual time mode and the TIME knob sets the delay time. Start tapping the tempo you want: the button starts blinking, keep tapping until it stays lit. Now you are in tapped mode, and the TIME knob is disabled. To get back to manual, turn TIME until you land back on the tapped tempo, and the LED goes off.
Every front panel control is detailed in Dub Mixer front and back panel controls.
Frequently asked questions
Ready to run your effects?
If effects loops are new to you, the general principle is covered separately in how and why using an effect loop (Send / Return).
Discover the Dub Mixer, hand designed in France, built to last.
