If you’re frustrated by the cumbersome and back-breaking size of your amplifier, a power amp pedal can take you one step closer to forming a far more portable rig.
Designed to fit on pedalboards, these stompboxes serve as ergonomic alternatives to traditional amps. And in this guide, we explain everything that they can offer!
As guitarists in the 21st Century, we're spoilt for choice when it comes to the huge amount of equipment that is available to us. It has never been easier for us to craft our favourite tones, and with the rise of digital modelling amps and guitar pedals in particular, many are deciding to forgo traditional valve amplifiers in favour of these smaller and more practical substitutes. They’re more versatile, reliable and portable.
Power amp pedals are a part of this trend. Seen as viable alternatives to conventional amp power stages, these stompboxes can serve the same purpose despite their small form-factors and relative affordability.
The final stage of a guitar amplifier is its ‘power amp’ section. While a preamp is vital for giving an amp its base tone, you could argue that a power amp is more important, as it is the section that is able to actually “amplify” sound. A power amp does this by boosting a guitar’s strengthened ‘line level’ signal (caused by the preamp) even more, so that it is powerful enough to be projected through speakers.
The reason why a guitar’s signal has to be boosted twice is because of the volatile nature of a power amp, which is kept away from a preamp as its large transformers produce a lot of heat and noise; causing interference.
12AX7 tubes are used almost exclusively to drive the preamp section of a valve amp. Power amp sections also rely on tubes, however you’ll find a lot more variation from brand-to-brand. This is because the types of tubes that are used in this final stage can heavily affect the overall feel of an amp.
For example, British brands typically use EL34 and EL84 tubes, which are known to break up softly and compress when pushed at high volumes. American amp brands, on the other hand, use 6L6 and 6V6 valves. These emit a cleaner and more open sound, which can be pushed harder without breaking up so quickly.
You guessed it - a power amp pedal is a floor-based unit that can emulate an amp’s power section. With one of these, you can essentially hook your entire pedalboard up to a speaker cabinet, so that you have an all-encompassing rig quite literally at your feet.
If you no longer want to lug around a heavy amp to gigs, power amp pedals eliminate their purpose and enable you to plug into a venue’s own speaker cabinet or even its front-of-house PA system for direct monitoring. The sound guy will love you for it! And like with most preamp pedals, power amp stompboxes typically feature solid-state circuitry for dependable operation.
Of course, power amp pedals gel with preamp pedals; it’s what they’re primarily designed to work with. However, it’s not like you have to use a preamp stompbox with a power amp pedal, as in fact, a lot of guitarists use overdrive and distortion pedals instead of them. This can be attributed to the blurred line between these effects, as a lot of distortion pedals can more or less do what preamps can; they boost, distort and compress your signal. You could just argue that they are sometimes marketed differently.
Some guitarists also use power amp units in conjunction with their multi-FX pedals too. Premium multi-FX and amp modelling products like the Line 6 Helix don’t necessarily need a power amp, as they can be plugged directly into compatible FRFR (full range, flat response) cabs. However, simpler multi-FX units don’t have this functionality, and therefore a power amp pedal can bridge the gap.
A power amp pedal should be placed at the very end of your signal chain. This is so that it can boost and send your entire processed signal to a dedicated set of speakers, just like a power amp in a traditional guitar amplifier would do.
If you’re confused about where the pedals you’d typically place in an effects should go, it’s not too hard to figure it out. As an effects loop is placed between an amp’s preamp and power amp sections, you can just treat those pedals in the same vein. For example, a power amp pedal should always go at the end, so therefore your modulation and time-based effects should be placed just before it, with your preamp/overdrive/distortion pedal(s) before those.
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