Are you confused if you need a pedalboard patch bay, junction boxes, I/O boxes and how to best utilize them (or if you need them at all)? Do they actually help, are they worth the investment, do you really need to add one more thing to your signal chain? I want to cover some of the common mistakes and misconceptions in using (or not using) a pedalboard patch bay (or junction box) in the next few minutes.

First - let's talk about the difference between a patch bay and a junction box from my point of view. These terms can often be interchangeable. A patch bay in it's simplest form is an easy, affordable way to add a place to plug your guitar in and your amps out of your pedalboard. In this example, no added features other than convenience and less wear and tear on your input / output pedals.

A patch bay in the above example could be called a junction box. The confusion often comes because a junction box can tend to do what a patch bay does but then adds extra features on top. As an example, you might have a patch bay that has:
A. Guitar input
B. Left and Right Outputs (for stereo amps)

A couple of simple add-ons to this might be transformer isolation and polarity control. Like so many things in this industry, there are multiple names for these features. Terms like, ground lift and phase flipping, 0/180 degrees, transformer isolated outputs etc. Added features like this (and many more such as buffering, muting, re-routing, re-amping, insert points, midi control etc.) is what takes a simple patch bay and moves it to being a junction box. When the unit becomes more than just patching a guitar and amp to a pedalboard, it becomes a junction box.

Now your junction box might look like this:
A. Buffered guitar input with tuner out
B. Stereo left and right outputs to amps
C. Transformer isolation and polarity control on Right output
D. Master Mute on Stereo outputs

Now we've got the basics of junction boxes and patch bays covered let's move on to some common mistakes and misconceptions.

Thinking That Only Pro's Benefit From Patch Bays

Junction boxes (and patch bays) are a quick and easy way to streamline setup and tear down for your pedalboard. Professional musicians are setting up and tearing down their rigs multiple times a week. Therefore they need to make this process simple. Because of this it might make sense to put them in a completely different category to the once-in-a-while gigging or hobbyist muso. The players that don't rely on this gear for their income. Wouldn't it?

I agree and disagree with this statement. Evidently, even at a hobbyist level, guitar players are regularly spending $10k on their rigs just to get started. I've had customers spend 10k just on their pedals alone, let alone a guitar and amps.

A patch bay allows you at the bare minimum to save your first and last pedals from constant abuse. Allowing you to protect your investment.  It's much easier to replace a jack on a patch bay than it is on a PCB mounted pedal. All things considered, if a $75 patch bay allows you to prevent sending 1 pedal away for repair, it's been worth it.

Beyond this, even the hobbyist musician (from my experience talking to them every week) often wants to have simple routing options easily available. The most common request going something like this:

"I want to be able to easily run my rig in mono, dual mono, 4 cable or 5 cable method without having to spend 10 minutes rewiring my board"

or

"I want to be able to run stereo, wet dry or wet dry wet in series or parallel without having to re-patch my rig"

Without a junction box - this is going to take time, create more wear on pedals and cables and eat into your practice time. With a junction box - no problem.

Even at a hobbyist level, patch bays and junction boxes can save you time, money on repairs and simplify your rig and make it more pleasant to play.

Combining A Pedalboard Patch Bay And Junction Box The Wrong Way

There are a couple of seemingly minor issues that a newer user of a patchbay can easily overlook (I know this because I have made these mistakes early on in my career and want to save you the headache).

A really common occurrence is when using an angled pedalboard. I mention this because there are angled boards out there that have built in patch bays on the side (a place to plug your guitar in and your amps out).

I will often get guitar players coming to me asking why they have a buzz when they plug into their patch bay / patch panel on their angled board and almost always this is due to a shared ground (even when using a junction box with isolation / ground lift on it).

To understand whats happening, let's first make up a pedalboard signal chain to demonstrate this. Let's say you have a pedalboard that looks like the following:

Guitar --> Patch bay input --> Overdrives --> Volume Pedal --> Chorus --> Stereo Delay --> Stereo Reverb --> Junction box (with ground lift and phase correction) --> Stereo Patch Bay --> Stereo Amps

The junction box has the ground lifted on one of it's outputs (as it should be when running multiple amps) but the amps are still making a loud buzzing noise (there is a ground loop). When the player unplugs an amp from the patch bay, the buzz goes away. Doesn't matter which amp either.

The amps are on a shared ground even though the junction box is doing it's job. How is this possible if the junction box is lifting the ground as it should?

The patch bay!

The patch bay (where the guitar plugs in and the amps plug out) is re-connecting the ground after the isolation occurs in the junction box.

How do you correct this? Try plugging straight into your junction box and bypass the patch bay entirely. The noise should go away. If it does, the patch bay is most likely the culprit. Isolate the jacks on the patch bay. More specifically, the jack that the isolated output on the junction box is plugged into needs to be isolated. This is caused by the metal frame of the jacks being plugged into a metal panel on your patch bay. The isolated ground has now been reconnected after the junction box!

This hair-raising fact would have saved me hours, and a few grey hairs had I known it sooner. Make sure your junction box and patch bays are working together, not opposing each other!

Not Getting The Features You Need For The Venues You Play At

It's one thing to think about the features you need today, but what about in future?

This is a tricky line to walk. On one hand I do not think you should go overboard on features you will never use, but on the other I think it's wise to take a second and think about what you're most likely going to need in the upcoming years with your pedalboard.

Do you have tours planned? What new venues are you going to play at? Are you wanting to get into new routing options in future? Amp sims vs. real amps? Will both be used or just one? Will backline always provide the gear you need or should you prepare for alternate options?

As of today you might solely play a mono rig into the front of a single amp. Easy peasy. No need to overcomplicate things. In 6 months you're going to take this on the road and tour the US as the single guitar player in a pop band. Nicely done!

What happens if / when your single tube amp goes down mid-set? Do you have a plan for a quick fix?
A simple add-on to a junction box is a dual mono (or duplicate) output. Now at every gig you're going to run two amps instead of one. If one amp goes down mid-set, you're going to have backup already running and useable for FOH and your in-ears.

Another similar example is running stereo effects. You're running two amps in stereo. What happens if one goes down? Do you have the ability to quickly sum your stereo signal to dual mono at the push of a button or are you going to lose half of your stereo signal when that amp goes down?

Running real amps locally and amp sims on tour because you don't trust backline gear on the road? Why not add XLR outputs so you can send your amp sim signal straight to FOH and cut out venue DI's? Run an FRFR simultaneously off a 1/4" output off your board.

Pedalboard Patch Bay Further Reading

As you can see - thinking ahead can pay off huge if you spend the extra few minutes to think through what future gigs, venues and routing options may require.

Not every guitar player needs to have a junction, but I know it will pay off to consider what your current playing context is and how it may change in the near future. Will a junction box streamline your playing? Prevent premature damage to pedals you'll find it hard to be without? Add a safety net where there was none before?

Check out a thread on Reddit if you want to get other peoples thoughts on this with some how-to's as well!