Here’s a question I’ve seen come up again and again: “Which battery-powered amp should I get?”
In my past life as a software engineer, I learned this lesson quickly: asking the wrong question often yields the wrong solution.
Warning from a reader 9/26/2022: “I would never risk running a tube amp off of one of these power supplies outside. Without a proper ground you’re taking a daring step. Tube amps run very high voltage internally with current levels in the ‘no return zone’ meaning, getting zapped while playing in the outdoors could be that final gig.” (These days I only use solid-state amps through these things which is much safer overall, tube amps also drain the batteries very fast in comparison. -v)
In the early days, I’d nervously walk up to a more experienced engineer and start rattling off a hyper-specific algorithmic question, probably while fingering exact lines of code on the laptop cradled in my arms. My thought process was this: I need to prove that I have been really digging through the weeds and whittle my question down to something unambiguous to save their precious time while saving face. After some confusing back-and-forth I’d usually get the quizzical response, “what exactly is the problem you’re trying to solve?”
That, as it turns out, is first question I should have been asking. In the end, the more-experienced engineer would likely just google a term I had never heard of that precisely describes my problem, and present me with a handful open-source libraries (or a stack overflow post) that already solved it. Turns out all my prior digging was unnecessary. I got a better solution from a different angle.
In this case, the problem is perhaps this: I’m playing a rustic wedding ceremony while floating on an artisanal hand-whittled raft in the middle of a frog pond for a small audience of 50… this is purely hypothetical–I can’t swim and I’d probably turn down this gig.
In summary: I want to amplify my guitar without access to a power outlet. Now I might think, “clearly I need a battery-powered amp. Now which is the least-crappy sounding battery-powered amp and how much does it cost?” Wrong questions! How about: how do I power an amp without access to a power outlet?
With the same lithium battery technology used in electric cars and smartphones this is now possible in a package as small as a lunchbox.
These batteries are usually branded for camping/emergency use and include a standard 120V mains outlet. Various models are all over Amazon, but I got the best one I’ve found is this one by Ecoflow.
It charges fast (under two hours) has multiple USB and outlet ports and is supplies 288 watt hours. So if your amp is 60 watts, you can power it for almost 5 hours (288 / 60 = 4.8). But the real figure is much more, because your amp probably only uses 60 watts at full volume. If you’re like me, playing at full volume, or even anywhere near it, never happens.
I’ve powered my AER Alpha for multiple 2-3 hour gigs without recharging. I’ve also put some 15-watt tube amps through it, like my Fender Princeton Reverb. I’ve even plugged in power strips and powered multiple devices. I’ve loaned it to a buddy who powered a PA speaker (QSC K10) with it.
The only issue I’d report is that there can be some noise interference due to the transformer in the power supply. Be sure to move it a few feet away from the amp. Also, single-coil pickups tend to hum more when not touching the strings since there isn’t grounding to speak of. If anyone knows a solution to this, let me know. Although, perhaps I’m asking the wrong question 🙂
Update!: I’ve found that this model by ecoflow is much better at managing noise and also has much more features. I barely get any added hum on my dearmond FHC pickup. I believe this has to do with providing a pure sinusoidal power signal.
If you MUST get a battery-powered amp, I’d recommend something from Roland’s CUBE series. They run on AA batteries for a truly impressive amount of time and volume. Don’t bother with stuff with heavy, proprietary sealed-lead-acid batteries. Guess what, if you forgot to charge it you’re out of luck. If some ubiquitous AA batteries ran out, you can solve that problem much more easily.