Harley Benton GPA-100


This item runs exclusively on an operating voltage of 230 V and therefore requires a voltage transformer to run in your country of United States.

Compact power amplifier for electric guitar

  • Power amplifier in pedalboard format
  • Designed for direct use with a preamp or effect pedal
  • Power: 100 W into 8 ohms or 190 watts into 4 ohms
  • Class-D technology
  • Controls for master volume, bass, mid and treble
  • LED peak indicator
  • LED signal indicator
  • LED power-on indicator
  • Input: 6.3 mm jack
  • Loudspeaker output (4 - 16 Ohm): 6.3 mm jack plug
  • Power supply: AC 220-240 V
  • Dimensions: 162 x 100 x 64 mm
  • Weight: 0.8 kg

Note: A preamp is required for operation

Available since November 2020
Item number 464518
Sales Unit 1 piece(s)
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A high-performance Class D power amp in a pedal

Gone are the days of lugging around heavy guitar power amplifiers - and we can be thankful for it. Modern Class D power amps pack an enormous amount of power into a highly compact, lightweight package - and the Harley Benton GPA-100 is no exception. This little powerhouse comes in a pedal format and delivers an output of up to 190 watts at four ohms, making it the ideal solution for guitarists and bassists who are looking to make their rig powerful enough to always be heard, but also don't have a lot of space to spare. The GPA-100 features a three-band EQ, a master volume control, and indicator LEDs for signal and peak, so players always have a good overview of what is going on. What is more, its sturdy metal chassis ensures functional reliability even when the pedal is used under extreme conditions.

Immense power with a tiny footprint

Thanks to its compact dimensions of just 162 x 100 x 64 mm, the GPA-100 can easily be integrated into an existing pedalboard and provides a complete replacement for that heavy rack-mounted power amp. Its three-band EQ (bass, mid, and treble) lets you easily make final tweaks to the signal coming from your preamp, pedal board, or multi-effects unit and thus get your desired sound. Being the most important control, the master volume - which is located at the bottom edge of the pedal's robust metal chassis - features an extra-large knob. All of the potentiometers are firmly screw-mounted to the front of the pedal, so they will be safe from harm if they accidentally get stomped on. Rather than an internal fan, which could become irritating over time, the GPA-100 features sufficiently large openings at both ends of the chassis to ensure adequate cooling even during heavy use for long periods of time. To top it all off, two LEDs - one each for signal and peak - are provided to allow the incoming signal to be monitored and optimised.

A power amp for all occasions

Players who use guitar rigs of any description or modellers like the Kemper amp series and Axe FX Fractal systems, and of course bass players who want to make their preamp audible will find the GPA-100 an interesting alternative. The compact power amp's output of up to 190 watts at 4 ohms should be sufficient for a wide range of applications, and it also comes at the kind of highly affordable price that is typical of Harley Benton. The GPA-100 is thus a particularly interesting option for musicians on a tight budget. However, it also offers many benefits for professionals, not least of which is the balance it strikes between compact dimensions and high performance.

About Harley Benton

Since 1998, the Harley Benton brand has been catering for the needs of numerous guitarists and bassists. In addition to an extensive range of stringed instruments, Thomann's house brand also offers a wide choice of amplifiers, speakers, effect pedals, and other accessories. In total, the range includes over 1,500 products. Built by established names in the industry, all Harley Benton products combine quality and reliability at attractive and affordable prices. The continuous expansion of the range ensures that Harley Benton always provides new, exciting, and innovative products that keep players perfectly in tune with the musical world, day after day.

High performance in a pocket-sized format for rehearsal room and stage

Whether you are using the GPA-100 with a 1x12" cabinet for practising and jamming at home or pairing it with a 4x12" cab on stage, this little workhorse is easily up to both of those jobs. In addition to amplifying your guitar or bass, the GPA-100 also gives you additional scope to shape your sound to suit the room thanks to its three-band EQ. The robust metal chassis is compact enough to fit into your coat pocket or gigbag, which can save a lot of logistical headaches - an advantage that is not to be sneezed at. It has never been easier to have so much power at your disposal wherever and whenever you need it while going easy on your wallet at the same time.

255 Customer ratings

4.7 / 5

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215 Reviews

Tinitus on a Budget
Impurist 10.02.2022
Was searching for a discreetly-sized, emergency back-up power amp in case my live rig died on the road. It can (and does) happen and can be a gateway to a realm of nightmares.

The price initially made made laugh, but when something is that cheap you really have nothing to lose so I took a gamble. Believe me, I won.

A solid unit with metal chassis, incredibly simple to use, and thankfully NO WALL-WART.

The sound is transparent enough in a serious live situation for no-one, not even you, to notice you're essentially playing by the grace of a glossy, black brick...unless you want to mess with the provided low-mid-treble dials which can certainly add some character. I leave them at 12 and dial on my pre-amp though.

Anyone who says this runs "quiet" is using it wrong, or needs a hearing aid: it easily keeps up with my Mesa Boogie Roadster. Read the instructions.

As it stands, I am considering ditching my over-priced, over-weight valve amps to use this exclusively on the road. I could carry an extra 3 in a tote bag and keep my back, wallet and pride intact when the "real" thing fails.

Beyond impressed. I'm going to buy a couple more eventually.


INCREDIBLE value for money!
santu ronzu 28.02.2023
I have practiced 3 musical instruments for 30 years....owned tons of gear.


1. The value is incredible. This is a 190 watts power amp that fits in your hand. This is a similar design to the Seymour Duncan Powerstage, at a fraction of the price! I have other Harley Benton gear, one isolated power supply and one attenuator. All this Harley Benton gear exceeded my expectations, this is THE best lower cost, professional gear you can buy.

2. This is PERFECT for tube preamps or hardware amp sims. As oppose as other designs such as tube power amp, which colours the sound, which now I do NOT like anymore, the GPA is a class D power amp. Basically, this is a HI-FI power amp for your preamps. You do NOT want class A or class AB power amp for your Pod, if you want the power amp to reproduce EXACTLY the tone you hear in your Pod when you use it with headphones.

In the past I swore by tube power amps....now I do not! I STILL use ONLY tube preamps (not Pod or amp sims) but I am definitely a class D power amp convert. I do NOT want the power amp to colour my preamp. This is an old debate with tube amp guitarists. What happens with a tube power amp is that as you increase the volume, the bass and treble will roll off, and the mids will increase. But today I do NOT want this anymore. Today I want BASS, a modern metal tone. I don't want the bass to roll off! I want the power amp to reproduce EXACTLY the same tone, at ANY volume. THIS is what Class D power amps such as the Harley Benton will do. Also, a tube power amp will distort sooner. Why? Because tube power amps are more expensive, therefore it means less power for the money. But class D doesn't have this problem: Class D watts are far cheaper, which means you get more power, which means more HEADROOM, and so the power amp stays clean. Plus, it is a FAR MORE efficient form of amplification. Almost 200 watts in your hand! With class A or class AB whether tube OR transistor, this would result in much bigger and heavier gear (you need bigger components than class D), etc etc, and this adds to the WEIGHT and the COST. This is why class D power amps cost less. But 75 euros for 190 watts rms? Incredible.

3. The GPA has a powerful ACTIVE eq. So you can add as much bass, mids or treble as you want, AND you can also CUT these frequencies, which you cannot do with PASSIVE tone controls, found on MANY power amps that are a LOT more expensive than the GPA. So basically the GPA is the PERFECT power amp. Some people lamented the fact that the GPA doesn't have resonance control. But ALL power amps have resonance, in the GPA it is just fixed. BUT there's ACTIVE bass control, which is BETTER than resonance control, which is PASSIVE and thus weaker. The bass in the GPA can take your head off, but it doesn't get boomy. Also the treble doesn't get harsh. This works PERFECTLY with my tube preamps.

The GPA will NOT sound inferior to the Seymour Duncan. And it's made solidly, of metal. This is not some cheap Chinese rubbish. The GPA is perfect for pros too....you don't always have to buy famous brands. Frankly you'd have to be dumb to prefer the Seymour Duncan Powerstage to the Harley Benton GPA 100! They both do the same things!

4. the GPA will tell you if the preamp output is too loud and distorting the input of the GPA. It also has a protection circuit in case of impedance mismatches at very high volume. But if you use correct impedances, it will probably last a long time, like any quality gear.

5. With my Blackstar HT Metal tube preamp my setup is pretty much NOISELESS, even with Ultra gain! I usually use noise gates, but I don't need it now. Just incredible! And the tone is amazing!

CONS: Absolutely NONE. A tube power amp does NOT sound better to me, only a tube PREAMP sounds better than non-tube preamps. I have made extensive tests in the past, for example I tested my tube preamp into a tube power amp and a solid state power amp, and the tube power amp did NOT sound better. But both tube power amp and solid state power amps WILL colour the tone and compress it at HIGHER volume. Because they are all class A or AB. But Class D, as used by the GPA , is MUCH more transparent than class A or AB. Like I said, basically a HI-FI power amp for guitarists. In my case, this is EXACTLY what I want. But the other advantages, such as ridiculous price and size and weight, are huge bonuses of course. Class D power amps are the BEST! (If you have a great preamp!).

So be smart and BUY the GPA!

(EDIT: after further investigation, the claimed power rating (100 watts or 190 watts with the other impedance) is not RMS, which means the effective power will be less. However I am pretty much sure that the GPA 100 can put out at least 50 real watts, which is still a lot and surely enough to cover most gigs! so it's STILL a superb bargain. I now used it for several weeks and I absolutely love it! The active EQ is so powerful, even with a thin sounding preamp you can get a ballsy tone as you want, even turning the EQ a little bit really sculpts the tone. Or you can leave it neutral and get a HI-FI amplification for your preamp, at any volume.)


The Best Cheap Power Amp?
NickB1234 29.04.2021
I use this to power my HX Stomp into a 1x12 or 2x10 cab for jam nights and rehearsals.

As a power amp it doesn't respond like a tube power amp. Its response is more linear. The Fryette PowerStation in that respect is a far superior product.But, if you're starting out in the modelling world and want a cheap and cheerful power amp, then I can wholeheartedly recommend the GPA-100. The tone controls are effective for fine tuning your tone and it's compact enough to chuck into your gig bag.

Would I buy it over the Seymour Duncan PowerStage? Yes.


I wasn't convinced at first, but it's PHENOMENAL
born_of_lava_deathmetal 08.02.2023
At first I wasn't convinced to the idea. Just wanted to test and see what the hype is all about.

My concern was about bass+mid+treble EQ - instead of traditional depth/resonance + presence that power amp suppose to have

So treble is acting 100% like the presence in my Randall RM100, it works in frequencies of presence, not treble.
Bass isn't a traditional depth/resonance or it's waay more sensitive. You can completely shake your cab or remove the low-end. It's super cool.
Mid can almost turn your G12T75 speakers into V30's or you can scoop your amp to that early Scott Burns death metal sound.

Turn up mids in preamp and cut them in GPA-100 or vice versa, cut in preamp and crank up in GPA-100. It's another cool feature and extra tonal possibility.

I'm going to buy second GPA-100 to make dual amp rig!

I have no idea if it's loud or not - tested it only in bedroom volumes, read other opinions.