Help with merging guitar stereo outputs please

[sonolink]

A friend has asked me to build an A/B switch to send his guitar signal to 2 different fx chains made of stompboxes.
Each chain ends up in a stereo output and he would like to send them to a single stereo amp.
Do I need an active circuit for this, or can I just solder lefts to one jack and Rights to another one?

Thanks
Cheers
Sono

 

[Tubetec]

Why not feed both fx chains with signal all the time and arrange to A-B switch at the fx outputs to the amp instead ?

 

[Potato Cakes]

If you need the effects trail of chain 1 to carry on when switching to chain 2, you would just put the A/B switching at the inputs of both chains and then build a summing cable at the outputs. 10k-47k would be fine for the bus resistors. You may even be able to use 1k for this application.

If this is not needed, just do what Tubetec said.

Thanks!

Paul

 

[Tubetec]

Downside of the summing arrangement would be excess noise as both fx chains would be feeding into the mix all the time .

 

[sonolink]

Ok, this is my friend's setup:
https://ibb.co/NmvF7Vw
Guitar goes into comp/drive on the left. I was wondering if the last box on the right (ABY) can work without being switched...

Why not feed both fx chains with signal all the time and arrange to A-B switch at the fx outputs to the amp instead ?

I hadn't thought of that. That would be a splitter and a stereo AB at the end, right?

Would that work as passive?
Thanks
Cheers
Sono

 

[Tubetec]

There should be no major issue splitting a signal from the comp output , a simple Y cable should do that .
Your A-B box needs to take the two stereo inputs(4 channels) and alternate to a pair of outputs so a multipole stomp switch will be needed .

 

[sonolink]

There should be no major issue splitting a signal from the comp output , a simple Y cable should do that .
Your A-B box needs to take the two stereo inputs(4 channels) and alternate to a pair of outputs so a multipole stomp switch will be needed .

Ok, that sounds great but I've been trying to find schems for stereo AB switches and you need minimum a 4PDT for that and got no LEDs. Can't I use an AB switch at the beginning of the chain (less inputs mean a simpler switch) and a double (stereo) Y cable on the other end? Would that mean noise issues?

Thanks
Sono

 

[JohnRoberts]

Another concern about plugging one guitar into two efx chains at the same time is that lead guitar pickups are relatively high impedance so sensitive to loading. Consider a DI to buffer the guitar.

JR

 

[sonolink]

Another concern about plugging one guitar into two efx chains at the same time is that lead guitar pickups are relatively high impedance so sensitive to loading. Consider a DI to buffer the guitar.

JR

Each FX chain has buffered pedals in it so I think that would be ok.

My main doubt now really is why not switching between the inputs of each chain (since that would involve a simpler and cheaper switch) instead of switching between the outputs of each chain? Would there be noise issues or something?

Cheers
Sono

 

[JohnRoberts]

Not sure how much difference there would be in the switches required, that said switching the pickups could be more susceptible to stray noise.

JR

 

[sonolink]

Switching the pickups? I'm afraid there's a misunderstanding, there is no pickups switching.
Guitar is plugged in a Drive/Comp pedal, then the FX chain is split into 2 optional paths.

My question is if using a passive mono AB switching circuit AFTER the initial Drive/Comp and a stereo Y cable at the end is possible, simpler, pop and noise free like so:


Or I should go with the opposite, a mono Y cable AFTER the initial Drive/Comp and a stereo AB switching circuit like so:


Going with the first option obviously implies a simpler switch (a 2PDT, or a 3PDT to add some Leds to indicate the switch position). My main concern is pops and noise.

Thanks
Cheers
Sono

 

[ccaudle]

the first option obviously implies a simpler switch (a 2PDT

Why not use single pole?

 

[Whoops]

For that situation, I would build for sure an A/B box that switchs both Inputs and Outputs at the same time.
Something like this

 

[sonolink]

Why not use single pole?

A DPDT would give the option of grounding the inactive output and a 3PDT adding LEDs to indicate the position of the switch.

For that situation, I would build for sure an A/B box that switchs both Inputs and Outputs at the same time.
Something like this

View attachment 111572

Ok. What stompbox switch would you use?

Can someone PLEASE tell me if any of these passive switches will produce noise problems such as pops or any other. Please, please, pretty please...

 

[sonolink]

you would just put the A/B switching at the inputs of both chains and then build a summing cable at the outputs. 10k-47k would be fine for the bus resistors. You may even be able to use 1k for this application.

Sorry Paul, I have just noticed your reply. What do you mean by the bus resistors? Do you mean resistors to GND at the output jacks of the A/B switching box?

Thanks
Cheers
Sono

 

[Whoops]

Ok. What stompbox switch would you use?

As far as I can see it, it's as simple as using a common 3PDT switch if you want to switch both input and outputs and have no indication LED

If you want an Indication LED you need an 4PDT switch, also easy to find

Those 2 are really easy to do.

Other Option is using Relays, a bit more involved and more parts needed but also not harder to do.

 

[Potato Cakes]

On the last image you posted, the two red lines needs to be connected with a bus resistor and the same goes for the blue lines. You shouldn't connect two outputs together without resistors inline like you would with any summing network on a console. It might be okay since you won't be sending signal out both sets of outputs at the same time, but in general practice there needs to be resistors involved in summing outputs together.

Thanks!

Paul

 

[Whoops]

Can someone PLEASE tell me if any of these passive switches will produce noise problems such as pops or any other. Please, please, pretty please...

Yes, they can produce POPs if no Pull-down resistors are used.
read this:

https://griffineffects.com/info/troubleshooting/why-is-my-guitar-pedal-popping
http://www.muzique.com/lab/pop.htm

____


Also the option to merge/mic the outputs is not that good, you will have noise from both FX chains summed always at the output.
Do as I advised, Switch both Input and Outputs at the same time

 

[sonolink]

On the last image you posted, the two red lines needs to be connected with a bus resistor and the same goes for the blue lines. You shouldn't connect two outputs together without resistors inline like you would with any summing network on a console. It might be okay since you won't be sending signal out both sets of outputs at the same time, but in general practice there needs to be resistors involved in summing outputs together.

Thanks!

Paul

Oh I see what you mean. So one resistor would be placed between the union of the red cables and the output jack tip, and the other between the union of the blue cables and the other output jack tip? Is that correct?

Thanks !!
Sono

 

[sonolink]

Yes, they can produce POPs if no Pull-down resistors are used.

Thanks for the link. I had in mind to ground the inactive outputs and use the resistors you mentioned following this circuit:
https://generalguitargadgets.com/pdf/ggg_sw_ab_sc.pdf

As far as I can see it, it's as simple as using a common 3PDT switch if you want to switch both input and outputs and have no indication LED
If you want an Indication LED you need an 4PDT switch, also easy to find

Of course you're right! With a 4PDT I can connect everything!

Thanks a lot for the idea Whoops.
Cheers
Sono