Phasing and quality issues with running audio effect pedals in parallel

[LukeeeeBennett]

Hello,

I want to run a lot of pedals in parallel instead of series.

So, instead of


I need


Now, I saw a post about this a year or so ago and saw many talking about possible phasing issues and lack of power and tone when just plugging them like so.

Would I need to use an OpAmp buffer? I remember this being a possibility.
Do you think there would be phasing issues? If so do you know how I could avoid/fix them?

Thanks to all who contribute.

[Mark Hammer]

Though not always the case, the majority of commercial pedals are non-inverting. That is, the output is in-phase with the input. So, while the possibility for cancellation due to anti-phase signals is there, do not expect it to happen frequently. Moreover, there can often be advantages gained by deliberately inverting the phase of an effect. Your goal is ultimately to have the option of either, and not have one or the other impeded.

That said, running ALL one's pedal in parallel is no more ideal a strategy than running them all in series. You may wish to have several "stations, where several signals in parallel can be mixed down to mono and then fed to a splitter and second set of effects in parallel, which are subsequently mixed down to mono and so on. In other words, don't let the advantages of parallel preclude the pleasures of series.

So, your "ideal" system might be 2 or 3 "stations", consisting of splitter/mixer modules (let's say 3 out / 3 in), with one of the inputs having a phase inversion option, so that whatever you might have that has the "wrong" phase output can be corrected, and so that you can explore what happens when two or more signals that are normally in phase are "turned against each other".

Mono in -> 3-way splitter -> 3-in-mono-mixer w/phase inversion in one input -> 3-way splitter -> 3-in-mono-mixer w/phase inversion in one input.....etc. -> mono out

Note that if you make this as several separate "modules", you would have the option of configuring it such that you end up with multiple outputs, rather than only a mono output. Given how many stereo effects there are out there, that's not a bad option to have.

[LukeeeeBennett]

That said, running ALL one's pedal in parallel is no more ideal a strategy than running them all in series. You may wish to have several "stations, where several signals in parallel can be mixed down to mono and then fed to a splitter and second set of effects in parallel, which are subsequently mixed down to mono and so on. In other words, don't let the advantages of parallel preclude the pleasures of series.

This is certainly the easy way around, but in my design spec I must stick to having all pedals in parallel. Could I put one big 6-in additive mixer at the receive end, so all the signals come back together, then each recieve end can have a phase invert button?

Thanks for the help.

[Mark Hammer]

I suppose you could, but if you have the option to stick whatever effect you wish into any given send/receive loop, then you probably only need to build in phase-flipping to a few. Save yourself the cost of the toggles and the nuisance of the machining and chassis legending.

[LukeeeeBennett]

That's very true actually, good idea. Thanks for the help.

[Guitarist]

Did this work out for you?

I was just redoing my pedal board and was thinking of //'ing my phaser and chorus, and maybe delay too. I might try it with all without resistors and straight cable on the output sum. But input and output impedance Ωs would be a third which is bad as I'm likely staying truebypass and non-buffered.