Guitar pedals are a great way to experiment with the sound of your instrument. However, they require electricity, and when you’re using more than a couple, it can get messy. Some will run on batteries, while others are thirstier for more current and will only work with a plugback. There are a great many solutions out there, but most people with more than a few pedals to power will end up going to some kind of mains powered solution. [Don] is here to show us that it’s not the only way.
Mains power is great for some things, but where pedals are concerned, it’s not always perfect. There are issues with noise, both from cheap power supplies and poorly designed pedals, and it means you’re always hunting for a power socket, which is limiting for buskers.
[Don] realised that the common drill battery is a compact source of clean, DC power, and decided to use that to power his rig. By slapping together a drill battery with a pre-assembled buck converter and a 3D printed adapter, he was able to build a portable power supply for his pedals. Thanks to the fact that the vast majority of pedals use 9V DC with the same input jack design, it’s a cinch to wire up. With an appropriately sized buck converter, a drill battery could supply even a hefty pedalboard for a significant period of time.
Overall, it’s a great hack that solves a problem faced by many performing musicians. We’ve seen our fair share of guitar pedals around Hackaday – perhaps you’d like to see how one makes it from concept to production?
https://www.youtube.com/watch?v=ueudFMLsRzk&feature=youtu.be
Buck/Boost convertors of the inexpensive variety often have significant high frequency ringing on their outputs. Adding a couple caps, say a .1uf, 10uf, and a 3300uf does a pretty good job of cleaning them up. Without the caps, your nice stable DC source is probably no better than a switching wall wart though.
Good tip. I think the ideal would just be a megafat 9V battery for the sweetest, purest organic DC but hey, who’s got one lying around?
8 AA rechargeable NIMH batteries in a radio-shack clip with an added in-line protection diode end up being just about perfect, with an average 2200 mAh capacity and 9v output. Bonus… the pack has a 9v battery clip output on it.
Why use such a huge capacitor and rely on the wiring resistance for your lowpass filter? 86 the 3300uF cap and whack in a series choke (something on the order of a milliHenry should do for most buck converter frequencies) in front of the 10uF capacitor, mischief managed.
If you use a switching converter, you can look at the output on a scope and design a very effective LC filter to get rid of the noise. The converters frequency should be pretty constant. Why shotgun parts when it is not that hard to design a proper filter?
Mainly because I’m lazy.
That combination of caps works fine most of the time, and I don’t have to explain how to design a proper one.
Using a buck/boost converter for pedals is not something I would do anyway.
“Don] realised that the common drill battery is a compact source of clean, DC power, and decided to use that to power his rig.”
You know what else is a clean source of DC power? Any decent quality battery. Drill batteries are proprietary grossly overpriced things because of the tool making company wants to make a big profit off the batteries.
The usual sources sell very inexpensive battery boxes for all standard batteries. An 8 pack of NiMH batteries gives you 9.6v and is very cheap to have a few packs. If that’s not enough power you can use 18650’s with a suitable charge circuit.
Indeed. It’s usually cheaper to buy a new drill than a new battery.
A new battery for my Bosch will cost £79. B&Q the same model on offer for £39 a few months back so sometimes you can even get two…
The drill battery could very well be a shell around several 18650s. It does provide a convenient charging solution though
Many actually are just that. A plastic shell containing an array of 18650’s and a charging controller.
What powers the amp? Or is this for headphones only?
I think it’s time the electric guitar get a little more electrified than 2 pots, a cap, and a switch. My slide has a laptop battery, Digitech processor, line in, 12watt amp, and speaker. The volume/wah pedal is in the bar-slide, finger fast.
With my processor I got whine from it’s own bucker, it would disappear with a wall wart but whine in the battery powered setup. Finally I got out the isolation transformers, one input and two output. No whine! Sometimes ground loops can mess up things. Of course I tried filtering the DC with no effect.
My pedal board has about 15 pedals in it. I use a 7.2 amp 12 volt lead gel sealed rechargeable battery. All 9 volt guitar pedals will work perfect on 12 volts with no damage. This type of battery will work for a few days of performing time depending on the current draw of the pedals one uses. The only disadvantage is that the battery is a bit large and heavy but that is a small inconvenience. My amp and mixer are battery powered too. I am totally free from the need of mains power.
That cheap noisy step-down converters are not something you want to see in any audio application. Linear regulator would probably be a better idea, but with efficiency penalty, 50% or so with 18V battery pack. Heat probably wouldn’t be a problem with low current draw pedals have. I think it would be wiser to make 2C or 3C protected pack with Li-ion cells or phone batteries.
Well I think the combination of the step-down to get to the ballpark and a linear regulator to get some smooth dc goodness would be an efficient alternative.
Linear regulators have a surprisingly forgiving input range. The catch is you must have an input 2 volts (at least) higher than the desired output. And heat sinking the regulator is a good idea.
My daughter got an electric guitar for Christmas.
I showed her this article because she didn’t believe that guitar pedals existed.
If she knows some electronics just show her some of the many sites devoted to pedal making (diystompboxes.com, muzique.com, etc). there’s a huge load of information out there, and parts are cheap. Good ears and musical taste are not, though:)
Or… ditch the pedal board. Definitely not as simple, but this can replace virtually every stomp box.
http://rakarrack.sourceforge.net/
and
https://www.soundonsound.com/reviews/native-instruments-audio-kontrol-1
NI have a couple newer offerings too, but I’m still using my 6 year old one.
Runs reliably with 5ms latency (undetectable) on my 4 year old laptop at 2x CD quality sampling.
This is interesting, something I think I’ll pursue for her…
(if I’m reading this right, I convert an old laptop to Linux, install JACK, and Rakarrack, hook up the/a MIDI controller…)
The DL-4 is a very popular looper/FX pedal, it runs on 9 or so volts Alternating Current. I have one. I don’t know what’s up in it’s power supply. I had to give it it’s own winding on a multi-winding transformer that powers my base-board-cords-case along with +&-15volts and 9DC.
I have a BYOC Tri-boost and the Germanium transistor is VERY finicky when it come to power supplies. The best sound comes from a 9-volt alkaline battery. When I use rechargeable batteries or A/C adaptor it is very noisy to the point of being annoying.
All AC adapters are not created equal. Some low priced ones are very noisy. Others are quiet; I use a Roland PSB-1u. It’s powering 14 pedals of various brands. It’s completely quiet. I bought a cheap unnamed brand online from Chine and it buzzed like a chainsaw.
Germanium transistors are very finnicky as I found out firsthand. I’ve read that they sound better when cool, so they’ll keep the pedals in the fridge before recording with them, but this is going back a bit.