Pre-amp / Amp Simulation Pedals

A little while ago Chris (the other half of The High Hollers) and I each bought a Bose S1 Pro active speaker. It gives us a very convenient small PA to play through, and the battery power means we can take them anywhere. They sound great for vocals, guitar and, of course, acoustic harmonica.

Bose S1 Pro active PA speaker

What they won’t do is get you that crunchy, creamy, high-gain blues harp sound that a traditional tube amp will. This fired my interest in the various pre-amp or amp simulation pedals that are becoming popular. These are handy devices that can be plugged straight into a PA system – or indeed the S1 – at a gig – and simulate the kind of breakup you get from a tube amp.

Using one of these devices, along with the S1, I can carry all the gear I need for a High Hollers gig in two hands and a backpack. Even if we’re bringing our own PA! That’s extremely cool.

My criteria were I needed a compact, hassle-free solution, and if at all possible it needs to have the option of battery power.

I’m not looking for the best possible sound either. If I was I’d get a good amp and deal with the hassle. I don’t think we’re quite at the point where the technology can identically replicate the sound of a good tube amp cab with quality speakers. What I want is a decent sound that I can dial in reliably at different venues. “Good enough” really is good enough in this case.

Obviously, the cost is also a consideration. I don’t mind paying for quality gear if I can justify it, but things need to be in the realm of the reasonably affordable.

I did a lot of research, reading and listening while trying to find the right box for my needs. Below is a little summary of what I found, and what I ended up with. (Note: Prices checked in October 2022)

Lone Wolf Harp Attack / Alpha Wolf

The Lone Wolf Blues Company are very well respected in the blues harp community. They design and manufacture pedals specifically for harmonica players, as well as a harp amplifier and microphone.

I’ve had my eye on the Harp Attack since it was released some 10 or more years ago. It’s basically an amp in a pedal. What makes this different to most is that it actually contains a vacuum tube, like a real amp, so the breakup it provides is genuine, not simulated with clever electronics. They can be plugged straight into an amp, PA mixer or active speaker and, as a bonus, can be battery powered too. The harp attack costs around £180.

Lone Wolf Harp Attack

This box is very compelling, it seems perfect for my needs. The Alpha Wolf is even better though. This combines the Harp Attack circuitry along with Lone Wolf’s spring reverb and Harp Tone+ pedals, all in one box. The price tag is high at around £370, but this covers a lot of sonic territory. Sadly, but understandably, battery power is not an option.

Lone Wolf Alpha Wolf

Fat Tone Amps Fat Box

Fat Tone make bespoke harmonica amplifiers, working with the player to find the right sound for them. The Fat Tone Fat Box though is something different. It’s a tube amp without a speaker, and it looks fantastic. Very reminiscent of those old valve PA heads, it’s designed to sit between your mic and the PA and provide the tube break-up we’re after.

Fat Tone Fat Box

I’m slightly concerned it might not be too rugged with those tubes sticking out of the top, but it is small and Fat Tone provides it in a fitted carry bag. Probably best to keep it off the floor though, or someone is bound to stamp on it.

Sadly I’ve not had the opportunity to play through one of of these. It’s not cheap at £395, but it’s a quality product I’m sure, and very tempting. No battery power though.

Quilter “Blocks”

Harp players (and guitar players) are incredibly snobby about their tubes. And there’s a good reason. There’s just something about the sound (and there’s even some science about the harmonics produced by tubes vs those created by solid-state technology). Quilter is a company that has convinced many guitar (and harmonica) players to ditch the tubes with their Block series of pre-amps.

I have to confess again I’ve not had the opportunity to play through any of their amp-in-a-pedal solutions, and they have quite a few. Nevertheless, I thought it was worth mentioning because they get a lot of positive notice, and I’d certainly like to try them.

Joyo American Sound

I find this thing really interesting. It’s a (very) cheap clone of the no-longer-available Tech 21 SansAmp Blonde. The Tech 21 Blonde itself sought to replicate the sound of various vintage Fender amplifiers. By all accounts, it’s a very close clone, too. I’ve heard of people leaving the Sans Amp at home at using the Joyo quite happily in its place.

Joyo American Sound

What’s also interesting, is the same circuit – or one so similar the differences are irrelevant – is also available in pedals from a few other manufacturers. Thomann‘s house brand Harley Benton does a version, there’s a Caline version and I think the Horse American Sound is the same thing too.

Whatever version (I’ve played the Harley Benton and the Caline), this thing is a cracking little pedal for coaxing some convincing amp-like grit out of a speaker.

They may not be the most durable pedal out there though. I’ve fried one – I think bad electrics were to blame – and another one died when I dropped it down a staircase. Of course, both of those were user errors so it’s probably not fair to fault it too much. Anyway, at a price somewhere between £25 -£40 (even less used) and with the option of battery power this is a no-brainer. I keep one around and use it occasionally. Very handy for a backup too.

Tech 21 GT2 SansAmp

Talking of Tech 21, the GT2 SansAmp is a bit of a left-field option. I have one of these I use for guitar and it works surprisingly well as a harmonica pre-amp too, as long as you stick to the Tweed amp options. At a cost of around £200 and not sounding as compelling as the Joyo it’s not the best choice but it’s certainly usable in a pinch.

Tech 21 GT2 SansAmp


I’m sold on the idea of going straight to PA. As I mentioned above, I don’t think the sound matches a good amp but it’s damn close and – for me – the convenience is a clincher. I often use public transport to get to gigs and lumping even a small tube amp around on a bus is no fun.

In the end, I went for the Lone Wolf Harp Attack for my primary pedal, and I keep an American Sound around too for a backup (In fact, I prefer the American Sound for busking. The Harp Attack is very power hungry, and needs two nine volt batteries which drain very quickly).

I like the Harp Attack a lot. It does everything from light grit to a quite heavy distortion and the tone controls are responsive and useable. It’s voiced very well for harmonica, as you would expect, and is an all-round quality unit. It does require an 18v adaptor to use mains power though, and you need to buy that separately.

I could use the Harp Attack by itself but I went a bit further and paired it with a Boss RV-6 reverb pedal. I use this for both electric and acoustic guitar too, so it puts in the hours. I use the spring reverb setting for harmonica. I put both pedals on PedalTrain nano board along with a DI box, just to cover all the bases.

Harp Attack, Boss RV-6 Reverb and Radial passive DI

I’m completely satisfied with this setup. It’s small, light, convenient, versatile and can be completely battery-powered if needed. For bigger gigs, or recording, I’d probably prefer to use an amp, but I’d be happy with the minimal rig too.