Help making a hardware only sound processing rig

So I am trying to put together a sound manipulation rig using only hardware (I want to leave my computer out of it). The main goal of this would hopefully be to have 2 inputs into the chain, an instrument and an aux in, and be able to somehow switch between inputs for individual manipulation of the different inputs. Also, I do not have a mixer and am trying to avoid purchasing one, at least at this point, due to lack of funds. I currently have a number of effects pedals including Boss distortion, phase shifter, and auto wah pedals, a Small Clone chorus, and a Boss DD-20 giga delay that will be in the chain. I am also looking into some sort of pitch shifting pedal. Anyway, is there a way to have 2 inputs into this whole chain, one being an instrument and one being aux in? I know about input switchers that allow for 3 or more channels to be plugged in at the same time and switched between. However, I am worried that if I put one of these before the chain, only the input that it is switched to will be playing. I need for all the tracks to be playing that are plugged into the input switcher and just switch between inputs for manipulation of the individual signals. Additionally, are midi controllers out of the question for a setup that excludes a computer? (I am new at using midi equipment) I was also looking at dj-type rigs that allow for individual manipulation of several simultaneous tracks and also have midi capabilities. It would also be very cool if I was able to manipulate the instrument line in with a midi bank of synthesizers. Like I said, I am new with most of this and on a rather small budget. Any help is much appreciated! Thanks in advance

So you have an instrument (what?) and an “Aux” output (from what?)
These will then go through effects, or not, depending on the “switch” settings?
What happens then? They go into a Mixer and then into an amplifier > Speakers?

so I dont have a mixer now and I’m trying to avoid getting one. The 2 inputs, instrument (which will be a guitar or an electric banjo) and aux, which might be a digital track recorder playing pre-loaded samples, will, ideally, both be going through the effects loop while they are both playing (that is, while a sample sound is playing and the musician is playing). I sort of imagine the 2 inputs going into an input switch box, then through the effects loop, and to a PA system. This rig is for doing things in real time and possibly live performances. I think most of this is doable, except I fear that when I have the input switch box on, lets say the guitar (or electric banjo) so that I can alter the applied effects in the effects loop on one input signal at a time, the other input will be muted. I want both inputs to be playing simultaneously, regardless of what channel the input switcher is on. If it is possible, I want the input switcher to switch between what track is being controlled via the effect pedals, not what track is simply playing. I hope this helps…and more questions you have about the setup, please ask! thanks for the reply

In short, I want to have control of 2 different inputs through the same loop and allow for simultaneous playing of both inputs while being able to manipulate effect settings, using the pedals in the loop, on one input at a time.

MIDI is machine control, not sound. I tell the computer to play a note and it sends a MIDI command to my keyboard to press a key. Full stop. No sound yet. The keyboard actually makes the sound and you need some separate way to record it.

I’ve read this through multiple times and I’m still fuzzy on what the goal is. You have, say, a guitar and a keyboard and you want to be able to real time switch them into effects channels as needed and then on to an audience (or recorder).

The first-pass impression is you’re trying to avoid buying a full quota of effects devices for every instrument. I suspect there will be so many restrictions with a switching system that you won’t be able to use it in a real performance. You have to be able to insure that two different instruments never arrive at the same effects generator, which means you need to program exits as well as entrances.

I suspect the settings on each effects generator will not be the same between two different instruments, although that’s a production decision.

We have relatively simple multi-channel mixers at work, but they only have really simple equalizers in each individual channel. The real heavy lifting is the single digital effects package after the mixer and before the Line-Out.

These mixers do have Effects Send controls, but there’s usually only two and you sound like you’ll need many more than that.

I can see a few weeks down the line when something doesn’t work right and it’s impossible to fix. “The Gibson works through the Boss pedal and the echo generator unless the Yamaha keyboard is switched into the flanger…”

That day I call in sick.


You need some sort of mixer to combine the signals at the end.
Do you have any experience of building electronic projects? (soldering and stuff like that?)

I don’t have any experience really with soldering and things of that sort. The more I try to work this out, the more I think its not really reasonable without a mixer (which is what I was trying to avoid having to get right now)…oh well, thanks for the help anyway

That may not be a cure-all for you. Many mixers only have two Effects Send controls – two pathways out of each individual sound channel. Then there is one control for each to insert the effected sound back into the stereo show. Say one is an Echo and the other is a Flanger. You’ll get the Echo or the Flanger, not both. The pathways aren’t recursive.


You’ve still not said what you are plugging into at the end of the effects chain. There may be a reasonably low cost solution, but you’ve not given much information to work with.

I would be going into a PA system after the effects loop

Your PA system?
Does the PA system have a mixing desk, or a mixer amp?
Does it have 2 XLR inputs and a 1/4" jack input that you can use? (3 separate inputs total for you to use)

A mixer really seems like the right solution. It’s exactly what you want to do… Mix or select different inputs (to your effects chain). How do you expect to mix without a mixer? :smiley: And, a simple little mixer costs less than most effects pedals. I wonder if one of the guitar effects companies makes a “guitar mixer”?

However, you have a couple of unusual requirements… You need both instrument-level & line-level inputs, and you need an instrument-level output. (Most mixers have line-level outputs.)

If you know how to “build electronic stuff”, you can make a line-level-to-instrument-level reducer with 2 resistors (a [u]voltage divider circuit[/u]).

Or, you can build a [u]summing amplifier[/u] with an op-amp (and a power supply or a couple of batteries, and a few other parts). Mixers are designed around summing amplifers, so you are building a non-adjustabel mixer. You can alter the resistor values to mix line & instrument levels together, or you can add a couple of pots and, you’ve built a mixer.

Hmmmm… With enough experimentation, you could probably build a fixed-passive mixer with just two resistors. Take the voltage divider circuit, and instead of connecting one resistor to ground, connect that one to your line-in, and the other resistor goes to the guitar. You need high impedance (high resistance) to avoid “loading” the guitar, and the line-input needs a higher value for more voltage/signal drop. So, get a handful of high-value (high-ohms) resistors and experiment. I’d start with 10M ohms for the line-in resistor, and 1M for the guitar. (Or maybe 100M and 10M.)

Already been there (see post Mon May 23, 2011 9:22 pm )