Help building a “1 in, 4 out” box?

[Psychophonic]

In the spirit of an ABY type of pedal, I am wanting to build a unit with one input and four outputs. Each output would have an on/off switch and LED. This will be a desktop unit in a pedal enclosure, so on/off mini toggles for each output rather than stomp switches. Typical Boss type 9v DC power Jack for the LED's. I'm a diy novice but I can do this with some guidance.

First question. Is this idea as basic as wiring a bunch of mono jacks, spdt toggle switches, and LEDs together? Or will the one incoming signal degrade by splitting into four outgoing signals?

[stallik]

As you suspect, a passive box will give you issues. A much better solution would be a buffer/splitter - check out AMZ http://www.muzique.com/lab/splitter.htm
You'd need dpdt switches if you wanted to add led's.
If you prefer pcb's, try https://shop.pedalparts.co.uk/Spluffer_-_Buffered_signal_splitter_PCB/p847124_13319874.aspx

[Psychophonic]

As you suspect, a passive box will give you issues. A much better solution would be a buffer/splitter - check out AMZ http://www.muzique.com/lab/splitter.htm
You'd need dpdt switches if you wanted to add led's.
If you prefer pcb's, try https://shop.pedalparts.co.uk/Spluffer_-_Buffered_signal_splitter_PCB/p847124_13319874.aspx

Wow either option would suit my needs. I'll need to figure out how to incorporate the LED's but this is a great start. Thanks alot for the links!

[PRR]

If you have a decent output, a chip with little resistance after it, just split. I have run 13 loads on one output with provision for more (never needed). That was a Pro-grade box but I don't think it was straining.

If you have a weak transistor or a final network with 100k pots, every added load will suck the level down.

It's the same as lights. Got 4 or 6 100W lamps and a decent extension cord? You will be fine. Want those light 500 feet into the woods? If you don't run a very substantial cable, they will be dim, and dimmer the more you throw on.

[BJM]

If you prefer op-amps you may want to take a look a this:

https://www.musikding.de/The-4Split-kit

For the led, I don't think you need a dpdt switch. The article on the AMZ buffer describes a mute switch, you could also use a spdt switch, one pole grounding the signal, the other pole grounding the led.

If you want to go further, add 4 2P4T (rotary switches and one 4P2T (foot) switch so you can choose between two different combinations  .

[Psychophonic]

Ok looks like I have a couple or three options based on your links. For my intended use of this device, I am wanting to run my guitar into all four inputs of this old preamp (posted here last month). Using a stereo pedal (Verbzilla), I've discovered that running into inputs 1 and 2 and cranking the gain really thickens the fuzz. So I'd like to try stacking all four channels for max fuzz. Based on this, is there a build/pcb/circuit best suited for my need?

[BJM]

Hi

Both PCB's mentioned earlier should work. I don't know the Verbzilla but if it has a mono input with a stereo output you would only need a three way splitter.  Not sure how reverb before fuzz would sound, most people do it the other way around .

[Psychophonic]

Hi

Both PCB's mentioned earlier should work. I don't know the Verbzilla but if it has a mono input with a stereo output you would only need a three way splitter.  Not sure how reverb before fuzz would sound, most people do it the other way around .

Thanks. I was merely using the Verbzilla (in the off position) as a splitter for testing the idea of stacking the preamp's channels 1 and 2 and cranking the gain of each. The amount of fuzz produced is thicker than channel 1 alone, and with surprisingly low signal noise. So I'd like to hear all 4 channels in action.

[BJM]

You're welcome. So both splitters should do the job. I read on the AMZ website that op-amp buffers appear to be a bit more sterile than transistor buffers. I've build a few op-amp splitters, there not really difficult, you could also build one on vero or stripboard.

http://www.muzique.com/lab/buffers.htm

[MrStab]

Buffers only sound sterile if someone tells you there's a buffer and it sounds sterile. Similar psychoacoustics can also make them sound like "highly skilled engineers making a device whose output replicates the input as linearly as possible"!

[StephenGiles]

Craig Anderton did an article for such a circuit, possibly in Guitar Player back in the 1980s.

[R.G.]

Yep - "sterile" tends to mean "didn't distort enough in ways we have come to expect". There are some circuits which introduce some very slight high end distortion that sounds a little harsh, without being obvious, and that's probably the origin of sterile = bad.

If you're doing a multiway splitter, unless all the places you split to are in the same case and powered with the same AC line cord, you'll probably run into hum problems due to the differences in AC line leakage between boxes.

One way around this is to transformer isolate. Here's one way to isolate from AC line hum/grounding that a number of people have used with multiple guitar amps and like. You can largely leave out the switching stuff if you don't need switching. (no complaints yet about "sterile"    )
http://www.geofex.com/FX_images/TransformerSplitter.pdf

[mozz]

Quickest way, solder a jumper across all 4 inputs, plug in, play.

[stallik]

Mozz & PRR talk common sense and remind me that the best solution is usually the most simple. It doesn't get easier than connecting all the inputs together so it's the first thing to try. IF that gives you a weak signal, try the buffer/splitter. If it hums, try RG's hum free splitter.

Reminder to self: try the easiest things first 

[BJM]

Craig Anderton did an article for such a circuit, possibly in Guitar Player back in the 1980s.

Project 26 in "Electronic Projects for Musicians", the "Spluffer"