Using Stereo Pedals with the Mastermind PBC

Mastermind PBC, Tech Tips

Loops 7 through 10 are stereo capable on the Mastermind PBC. You can use them with mono pedals or stereo pedals. Using mono pedals is easy – just connect them with standard 1/4-inch cables and you’re good to go. However, as soon as you want to start using stereo pedals, you’ll be required to use some special cables to make sure everything works correctly.

Before we get to the cables, we should go over the pushbuttons on the rear panel. These are also crucial for proper mono or stereo operation.

Mono -> Stereo (out) – This button, when in the “out” position converts a mono signal coming in to the In 7-10 jack to stereo. This is done simply by connecting the incoming signal to both the left and right sides of the internal audio path. When this button is in the “in” position, the In 7-10 jack’s tip and ring are connected to the internal audio path’s left and right sides.

Mono Output – This button, when in the “out” position connects the left side of the internal audio path to Output A and the right side of the internal audio path to Output B. When in the “in” position, the left side of the internal audio path is connected to both Output A and Output B.

How to set these buttons can be summarized like this:
Mono signal into In 7-10, mono output – Mono -> Stereo IN, Mono Output IN
Mono signal into In 7-10, stereo output – Mono -> Stereo OUT, Mono Output OUT
Stereo signal into In 7-10, stereo output – Mono -> Stereo IN, Mono Output OUT

Now, on to cables… please note that these only apply if you’re using one or more stereo pedals. If you’re running all mono, you can use standard cables.

If you have a pedal with a stereo input and/or stereo output, you need an insert cable for each stereo connection. An insert cable has one TRS connector on one end and two standard (TS) 1/4-inch connectors on the other. This splits the TRS stereo connector on the PBC to individual left and right connections that your pedals need.

Insert Cable Diagram

If you have a pedal with a mono input, you need a ring disconnect cable. This is a name I just made up, because I don’t know of any “official” name for such a thing. This one has a TS plug on the pedal input end and a TRS plug on the Loop Send end. The tips of both jacks are connected together, and the sleeves of both jacks are connected together. The ring on the TRS side is not connected to anything.

Ring Disconnect Cable Diagram

If you have a pedal with a mono output, you need a mono to stereo converter cable. This cable has a TS plug on one end and a TRS plug on the other, but unlike the ring disconnect cable, the tip on the TS end connects to both the tip and ring on the TRS end. The TS end plugs into the pedal output, and the TRS end into loop return on the PBC.

Mono Stereo Converter Cable Diagram

There are other ways to do it, and depending on circumstances, you can, for example, use a normal 1/4-inch cable instead of a ring disconnect cable. But, it depends on the pedals you’ve chosen, what order you’re using them in, whether you’re routing in series or parallel etc. Following the above instructions will make any configuration work correctly.


The curious among you might wonder why we need these cables. The insert cables, I hope, are fairly obvious. The PBC combines its left and right connectors into a single connector to save space. Effect pedals have separate left and right connections. An insert cable converts from TRS to individual left and right plugs.

Mono pedals need to have their output converted to stereo. Otherwise, you will only get signal out of one side when the pedal is activated. The mono to stereo converter cable does this by taking the pedal’s output and sending it to both the left and right side of the loop return jack.

Mono pedals or stereo pedals with a mono input are a little trickier to understand. If you plug a TS (mono) plug into a loop send jack, the right (ring) side of the signal is connected directly to ground, shorting it out and making it inaudible. If you compare a TRS plug and TS plug, you can see that the area that contains the ring on a TRS plug is part of the sleeve on a TS plug. The right side of the internal audio path is connected to the sleeve through the TS connector. At the minimum, you’ll lose the right side of the signal. If the previous pedal in the audio path is mono, but converted to stereo, you’ll lose both the left and right sides of the signal. Using a TRS connector with the ring disconnected prevents this unintended connection to ground – the right side of the signal connects to the TRS connector’s ring, which is not grounded, and will not have any effect on the signal.

I hope this all makes sense. As always, please feel free to contact me with questions. If you follow the above recommendations for switch settings and cables, you will end up with a working system. You can get the specialty cables made at places like Best-tronics.


Mastermind GT 3.1.1 firmware now available

Mastermind GT, Product News

We’ve just released Mastermind GT firmware 3.1.1, which fixes a number of bugs. If you’re using 3.1.0, this fixes some issues you may be seeing. If you’re using an older version, this might be a good time to move up to the latest version!

Mastermind GT


Mastermind PBC wins the Premier Guitar Premier Gear Award!

General News, Mastermind PBC

The Mastermind PBC has recently won the Premier Gear award from Premier Guitar magazine. Premier Guitar has been covering a lot of pedalboard switchers lately, and we’re thrilled to see that they really like what the PBC has to offer. Thanks guys!


RJM Music Rig of the Day: Vision Guitars Pedalboard with RJM Mastermind PBC

Rig of the Day

Thanks to Vision Guitars in the Bay area for submitting this Rig of the Day featuring
the Mastermind PBC (Pedal Board Controller)

RIg of the Day: Vision Guitars pedalboard with Mastermind PBC


Review of the Mastermind PBC by Mitch Gallagher of Sweetwater

Mastermind PBC

Still thinking about getting a Mastermind PBC?

This review of the Mastermind PBC by Mitch Gallagher of Sweetwater might help you. Great comprehensive video of the PBC features including the Mastermind PBC Mac/PC editor.


Pete Thorn demos the Mastermind PBC

General News, Mastermind PBC, Rig Tours, Videos

Pete Thorn did an awesome video for us, showing off the Mastermind PBC and the pedalboard that Dave Friedman recently built for us. You can check it out here:


Interview with John Petrucci’s tech, Maddi Schieferstein, Part 1

John Petrucci, Rig Tours

We interviewed John Petrucci’s guitar tech, Maddi Schieferstein, early in September 2015.

This is a fairly long interview so we’ve broken it up into 3 parts and added photos. Maddi is a very nice and entertaining guy. We are invited back to do another interview in November when they build a new rig. Lots of surprises coming that we weren’t allowed to talk about in this interview so please let us know if you liked these interviews – it will inspire us to do more.

You can watch Part 1 here:

1. How did Maddi become a guitar tech
2. How did Maddi become John Petrucci’s guitar tech
3. The big gear disaster in Mexico that changed their gear – a bit of a discussion of their current gear.


Rack Gizmo CLEARANCE Sale

General News


We are discontinuing the Rack Gizmo. You can now SAVE $200 when you order on our website at while they last.

We’ve had a lot of questions as to why we are discontinuing it. People have asked, “is something new coming out to replace the Rack Gizmo?”

No, we have no plans to design anything to replace it. With the Effect Gizmo and Amp Gizmo/Mini Amp Gizmo, the Rack Gizmo’s functionality is duplicated.

All new products will be focused more on Pedalboard switching since that market is much larger.

Buy your Rack Gizmo now before they are sold out

Welcome to the new website!

General News

We’ve changed over to a new WordPress-based website that should work a lot better on mobile devices, and is easier for us to maintain. Please let us know if you find any errors or problems on the site.

The old blog posts are gone but if there is something important we can repost, let us know!