Two pedals in parallel (blending, splitter, mixer...)

[Elijah-Baley]

Hello guys, this is my new idea. I want in a a box a sort of blending circuit to connect two pedals in parallel, two distortion pedals, for example, and mix them.

This is the diagram:



I found some splitter, mixer and blend layouts, but I miss something, and I don't know what exactly I need.
I prefer veroboard layouts, and verified.

Thank you!

[GibsonGM]

Maybe this will help? http://www.runoffgroove.com/splitter-blend.html

[Mark Hammer]

Not clear if you simply think you are missing something or whether you've built this and something is just not working right.

I will note that, while most pedals will provide an output that is in-phase with the input, it is not a requirement for manufacturers.  The upshot is that,if one is running all pedals in series, phase doesn't matter all that much.  But if one is running two circuits in parallel, their phase coherence (i.e., both maintain same phase relationship, which inverted or non-inverting) can matter very much.

So, with that in mind, you might want to consider a simple phase-invertor stage as part of the splitter or part of the mixer.  If the arrangement is simply to provide two mixable paths, it only needs to be assigned to one of them.

[wavley]

I just built two of these, and at $6.95 it wasn't worth my time to lay out a pcb. http://www.guitarpcb.com/apps/webstore/products/show/3456364

It will do everything that you ask, including adjust the phase of the loop, there is also an insert loop (that I just jumpered because I just wanted to mix effect and dry)

[radio]

Something like this  

http://diy.thcustom.com/shop/parallel-mixersplitter-v4-2-pcb/

[blackieNYC]

The runoff groove has the (also Geofex) polarity reverser and the TH does not. You will want that feature.
Consider whether the blending pan pot shown, or two independent volume controls would suit your needs best.  If everything you blend has a output volume trim you can use the pan.  But if you blend something like a phaser or filter, you might want a little gain on the return op amps and independent volumes.  Might.

[Elijah-Baley]

Not clear if you simply think you are missing something or whether you've built this and something is just not working right.

I will note that, while most pedals will provide an output that is in-phase with the input, it is not a requirement for manufacturers.  The upshot is that,if one is running all pedals in series, phase doesn't matter all that much.  But if one is running two circuits in parallel, their phase coherence (i.e., both maintain same phase relationship, which inverted or non-inverting) can matter very much.

So, with that in mind, you might want to consider a simple phase-invertor stage as part of the splitter or part of the mixer.  If the arrangement is simply to provide two mixable paths, it only needs to be assigned to one of them.

I still didn't built anything, but I just did some research about this my idea, but I don't know what exactly I need to have two pedals mixed in parallel. And I even know nothing about the phase.

Maybe this will help? http://www.runoffgroove.com/splitter-blend.html

I found it, and seems very close to my intentions, maybe is perfect.

Something like this  

http://diy.thcustom.com/shop/parallel-mixersplitter-v4-2-pcb/

This seems good, too. It is pretty similar to the ROG project. I read the PDF document, and the applications of this tool are very interesting. If I get those are:
- Splitter: to use two amps at the same time;
- Mixer: to use two guitars in one amp;
- Clean Blend: to use one pedal in a loop and blend it;
- Effects Blend: to use two pedals in parallel. (What I want).

The runoff groove has the (also Geofex) polarity reverser and the TH does not. You will want that feature.
Consider whether the blending pan pot shown, or two independent volume controls would suit your needs best.  If everything you blend has a output volume trim you can use the pan.  But if you blend something like a phaser or filter, you might want a little gain on the return op amps and independent volumes.  Might.

I guess to have the polarity reverser is a good thing, but could I know why i need it? What if I don't have it?
I was thinking that one only blending pot (like ROG/TH Custom) is enough and easy.

Meanwhile, I found, finally, some veroboard layout:
http://diy-layout.com/68, but seems unverfied.
http://www.sabrotone.com/?attachment_id=3843, also this seems not verified.


So, I didn't find verified veroboard layout.

[Processaurus]

A switching idea for that scenario, a 2 in 1 pedal which has a bypass footswitch for each effect (distortion probably), but when they are both on, it is a parallel blend you get, with a dedicated blend knob and volume control:

http://www.aronnelson.com/gallery/main.php/v/Processaurus/rat_muff_switch.gif.html?g2_imageViewsIndex=1

No layout but it would be easy to perf. I may get some little daughter boards made from OSH park at some point.

[blackieNYC]

If you blend two pedals or pedal chains, and one pedal inverts polarity (circuit with an odd number of gain stages I think, or inverting op amps), the sound will be very thin.  The distortion products will be different, but the 83kHz of your low E will cancel itself out, maybe completely.   There may be a list somewhere, but the easiest and surest way to find out is to make a splitter blender and see what your pedals do. I have one with lots of other features (profile picture) but I haven't done enough blending to survey all my pedals.  Perhaps I could make them with a little sticker that tells me to turn on the polarity reverser.  Anyway, I can't imagine you won't find one pedal you really want to blend, but happens to invert the phase/polarity.  The blend pot idea is simple and easy.  My splitter/mixer is one of those ridiculous pocket knives with way too many thingies.

Ah - here is a very long list: https://www.thegearpage.net/board/index.php?threads/list-the-pedals-that-invert-phase.796444/

[Elijah-Baley]

Thanks guys.

My idea was mainly to have two kind of distortion pedals in parallel. I don't know if it is a good idea, but it seems to me good. For example, I could use a fuzz and a distortion. Like Tycobrahe (with no octave effect) and a MT-2 Diezel mod and to mix them. Or Fuzz Factory and Rat.

Let me see if I got it. Some pedals have the phase inverted, when those pedals are in chain it doesn't matter. But in parallel is a problem, so the phase inverter switch that have the ROG circuit inverts the phase of one of the loop. This make the two pedals in phase and make sounds good.
Something like that? Is it alright?

The ROG project seems right for me. Too bad, the Sabrotone layout isn't verified.

[blackieNYC]

you've got it.  Parallel is a problem when blended.
The GP thread linked above has all sorts of opinions on parallel splitting to two amps.  Looks like we should leave that topic there.

[Elijah-Baley]

Thanks, guys!
For the moment I want to build the ROG's layout, but is not my favourite method.
If meanwhile somebody verfiy some layout on veroboard I hope he let me know.

Just to talk, how do you see my idea to mix two kind of distortion pedals?

[blackieNYC]

Blending good. 50/50, 72/25, anything. Bass from one treble from the other, (probably metal possibilities there) Classic fuzzes paired with classic fuzzes, or with wacky stuff like uglyfaces and ring mods for a weird and unique schtik that is still musical. Or entire loops - dirt with flanger meets Tonebender with vibe.  Used a few of these. Or straight fuzz on one, 100% delayed envelope filter on the other. A stereo panner into two loops, with an LFO sending to one then the other, then mixed back together into mono - for a swirling modulation no single pedal will give, or a very slowly evolving sound. 

[Elijah-Baley]

Hello, very old thread, but it's mine.
I totally forgot it, and I open another thread almost like this.
In the end I built the circuit of the ROG Splitter Blend.
it's nice, but I would like some other options.
This is the new one thread about the ROG Splitter Blend with some mods I would like: https://www.diystompboxes.com/smfforum/index.php?topic=125018.0