Quest for a Portable Amp and Pedalboard

Apr 22, 2018 · 6 min read

Part 2 of my previous story on using a multi-effect guitar processor as a portable one-stop-shop for all home playing needs

This part continues on the quest to make a portable, USB battery powered, wireless guitar setup that’s easy to get into a start playing on a whim and that sounds good enough to compare with larger amp setups. All while using only commoditized inexpensive components.

However, my pedalboard expanded a bit since the last article.

The Marshall amp in the picture is just for decorative effects :)

There’s a few additions such as extra footswitches for the Boss GT-1, the Digitech Trio+, a mixer and a PolyTune 2 mini.

But mainly, there were a few issues with the previous setup that needed to be addressed while keeping everything battery powered.

Ground Noise

The first issue was that there was tons of resting noise in the previous system. was a pretty neat resource for debugging the noise source.

There was no AC anywhere in the system since it was all on a USB battery pack but there’s still likely a ground-loop-like hum causing issue.

The solution was luckily fairly simple. I swapped out the daisy chain with:

A USB->9v power supply with 4 parallel regulated outputs for 24$. The difference was night and day. With the isolated outputs, high gain amp settings are completely silent at rest.

I kept the adapter underneath the pedalboard to keep everything clean and out of sight


The previous setup also had 2 other issues:

The challenge is that most mixers have their own AC adapter plug that neither uses the 5.5mm/2.1mm pedal plug or are 12v or 5v. Mixers also tend to waste one of the channels being optimized for microphone levels and impedance.

Luckily, I found an uncommon mixer but a huge gem.

The Pyle Bluetooth 3-Channel Mixer:

And all that for 53$ which is about the same price as the Behringer Xenyx 302USB but is way better built with a full metal construction and has bluetoot.


Since the objective is still playing for fun at home, looping makes the sound way fuller and more fun.

The GT-1 has pretty much all types of effect pedals from octaver to wah to looping included. But using the GT-1’s looper turned out to be less practical. Since, as mentioned in the previous article, the GT-1 is missing a drum machine that makes it way more fun to play by myself. And without MIDI sync on neither the BeatBuddy Mini and GT-1, timing the external drum machine and the looper is basically impossible.

Even if you played a loop and pressed the start/stop almost absolutely perfectly with the drum loop from the BeatBuddy, a 1ms deviation will accumulate to a point where everything’s a mess after a couple of measures.

So I turned to the DigiTech Trio+ which had the drums and looper together (and self synchronized). It also has the bonus of having an interpreted bass player and is also a fairly bit easier to control than the GT-1’s looper which needs to be turned into looping mode first.

One challenge with it though is that it’s so geared towards a conventional amp with a separate pedal chain that it’s hard to figure out how to even wire the thing.

The DigiTech Trio+ has 5 I/O connections.

All of this works well if you had a single amp and make the assumption that the effect pedals change while playing but the amp is mostly static. But the amp in this case is the same unit as the effect pedals and we wouldn’t want to put the GT-1 after the Amp Out because if you change your GT-1 settings after looping, the looped recording gets altered.

Luckily, the looped recording saves everything that went through the Fx Send and Return loop as is so we can wire this as:

G10 wireless receiver -> PolyTune -> DigiTech Trio+ Guitar In -> Fx Send -> Boss GT-1 -> Fx Return.

Then send both the Trio+’s Amp Out and Mixer to 2 different channels on the Pyle Mixer.

This deviates from DigiTech’s canonical usage of letting the guitar’s pre-amp and cabinet simulation be inside the Fx loop instead of being after the Amp Out connection but since it records Fx Return and sends it out to Amp Out verbatim, it doesn’t really matter.


In total, this portable setup is still powered by a single USB powerbank.

The whole package can be picked up and played anywhere.

It consumes 1A from the G10 wireless system and 500mA from the mixer at 5v.

It consumes 100mA from the PolyTune, 200mA from Boss GT-1 (😱 so surprisingly low), 800mA from DigiTech Trio+ (I don’t know what it does with so much power) and an unknown but <500mA from the BeatBuddy Mini at 9v.

It comes to ~4A at 5v which is about 1 hour from a 5000mAh battery. All probably want something like

this 185Wh portable power block for longer sessions that will put me back to ~9h per charge.


Collection of tech tips and learnings

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