Behringer ADI21

This DI tube emulater/modeler unit has already been described. Great piece of gear! Incredible for the price actually. If I had to name a piece of gear that was a secret weapon, this would be it. Easy to use. Take some time to dial in the settings, listen to what comes out and tweek from there. BUT, you need to have some realistic expectations. It won't make your Strat sound acoustic. None of my electrics and even my Fishman Rare Earth magnetics don't sound great through this. But it will make many acoustic pickups sound much better, even fantastic! I give it a 9 for features. The only item I was wanting for is a phase reverse switch. And numbers on the dials would have been a good idea. But for $35 CDN - Well, Ok.

I use this only on two guitars - a K&K equipped Gold Tone dobro and a Baggs Ribbon transducer equipped Yamaha classical. These feed into a Mackie 1202 mixer. The sound of the Dobro is nothing short of stunning. And the same with the classical - very even rich tone. Keep in mind that both of these pickups DO NOT have preamps. They are both passive transducers - no batteries and hidden end-pin preamps. I have tried ALL the K&K preamps - the Behringer beats them. I have tried the Baggs Para-acoustic DI. Very nice but I think the Behringer is better. and for $35.!!

I have gigged with it for a few years and it seems pretty reliable. It has never let me down. OK, while it seems solid enough, don't start tossing this thing around. Behringer is not known for sturdy stuff. I've had my first one for 3 years - no problem - just take care of this puppy and it will treat you well. I bought a second for the classical just this week so there is the backup, if needed.

Not needed.

Its a great match for playing classical, roots acoustic stuff. If lost, I would pick up another in a heartbeat.

This little box isn't too complicated. It has really sensitive high/mid/low etc frequency pots so it's easy to get the sound that you want. That being said, I bought it to make my epiphone les paul sound like an acoustic, but after fiddling around a bit you realize that this pedal, despite it's name, is incapable of making an electric sound like an acoustic. It gets decent points, though for it's wide variety of tones that it can put out.

I actually use this pedal as a fuzz pedal most of the time. I set the Mids all the way up, MidFreq all the way down and Blend all the way up.

Then Lvl, bass and treble just adds some flavor to the distorted sound. The distortion is weakly fuzzy, not a lotta compression and over-the-top gain distortion...but it sounds very unique I think. It'll really fatten up your guitar sound and sort of get that jimi hendrix sound. Admittedly, I don't have much use for the fuzz pedal besides playing the occasional jimi, I also have a RP-90, that models a fuzz pedal, and I think the Behringer pulls it off better.

Oh yeah, I'm plugging an eiphone les paul into a fender blues junior

I've had it for 3 years now, don't play it 24/7 but it hasn't broken on me yet.

I'd probably use this as a backup if I were gigging, always have backups.

This is a decent, cheap pedal that can pull of some cool clean tones for whatever genre of music you play (i like to noodle around with all sorts of genres)

It also has the ability to pull of a pretty good fuzz sound which is a plus...so if you are looking for a cheap pedal to mess around on and get some weird/cool tones, this is the pedal for you. If it were stolen though, I probably wouldn't buy another one.

I just think it's cool that it can pull off a fuzz sound and have a lotta EQ'ing options for extreme tonal variety

Even tho some of the functions are counter intuitive its easy enough to use after an hour or so experimenting

With my tele with SD pickups I could make a nice mellow jazzbox sound. Couldn't really make a sound much like an acoustic guitar tho, so defeated the purpose in buying it.

During the second time of serious use started to make a noise like a bad fuzz pedal. the original sound is no longer available. I bought while travelling so could not return the item

I should have known better. I think with these pedals Beheringer are cynically causing a lot of heartbreak for young muso's and others with not much $. To be fair I must point out I had a v-amp for a while and that worked fine.

Very easy to use. The mid range sweep is powerful and is worth the price alone! I use it for my acoustic Violin fitted with a piezo pickup.

The piezo has way too high impedance, so the ADI21 lowered the impedance just nice to go direct into the mixer. A Violin has very nasty highs when used with a piezo...so the ADI21 tamed thoese highs and added a lot of warmth to it. The trick is to experiment with the all- powerful mid range sweep which made all the difference.

It has served me well for the last 2 years. I bought one more to use for other instruments. There's no limit on what instrument you can use it on.

Never had to deal with the local behringer co cos none of its products has ever broken down on me.

Buy this if you want a cheap but powerful acoustic processor. It really beat the crap outta other effects that cost 2-3 times more! Behringer has done it again with this impressive unit.

This unit takes more than one sitdown session to dial in. First, I used low guitar output and let the ADI21 do the boosting to a powered mixer XLR input. I still felt unhappy with the sound, a little empty. So, a month after buying it, I think I found the problem... I turned the -20 dB switch on and turned up my Peal Acoustic Electric Guitar to halfway... This way the ADI21 seemed to find the soundboard vibrations being driven TO the ADI21, not a lot fuller but noticeable... Now I am happy...

This unit is very quiet. I have used it both with the ground lift and without and like it without better (I guess this has to do with the PA setup and source). The effects do change quite a bit when adjusting the knobs but most of them I don't really need since I duo with a Yamaha keyboard and we both sing. I just needed a more dynamic acoustic. I will say you can fatten it up by boosting bass on the guitar and turning up the mid-freq about halfway (a neo-crunch type of sound)...

I have used this thing for about fifteen 2 hour practices and just changed the battery once, so, I guess that means about 15 hours or so per battery. I will buy an AC adapter but wouldn't use it onstage... I feel pretty comfrotable when we play gigs and don't bring a backup...

Never used... Would buy another if it broke but am brave enough to look into a different one at or below $50...

Acoustic duo with piano mostly covers... I wish unit had a chorus or reverb on it...

It took about a week of tweeking to get the sound out of this I was looking for. It was worth the effort though. I really enjoy the way
it sounds now. Much warmer, more expensive sound out of my cheaper equipment.

I'm using this with an Ovation Celebrity and a Behringer Firebird
practice amp. Without this the sound was alright, not bad at all.
With this the sound is bigger, fuller, more.

The blend part or the effect does more than expected, it's awesome.
The EQ with mid shift is also interesting. Well worth the small pricetag.

Everyone here knows it's made of plastic, get over it. Feels heavy
and well made. Don't expect any troubles. But then who does?

Don't need to worry about gigs, we're strictly a stay at home player.

I do not know.

No particular style, just have fun. I've tried to play for 20 some years. What I lack in talent, I make up with comedy relief.

I also own a Danelectro Fab Chorus and Fab Echo pedals. I sometimes
run these in a chain after the ADI21. Very nice.

I purchased and returned, a Zoom A2 before I got this one. The Zoom was amazing, but too much of a good thing. You could get thousands of combinations of sounds, but I wanted something simpler.

I bought this unit to add a mid-range control to my Behringer BDI21 Bass Processor. I figured I'd be able to cut the blend on the ADI21 and just adjust the mids, enhancing the sound of the BDI21. This doesn't work, but I am finding that I prefer the bass sound of the ADI21 to the BDI21!

There are only a few controls on this unit and they work well together. I found that trying out the suggested settings, even though most of them are geared towards guitar, gives you a good place to start from in finding your bass sound. I actually don't like the suggested "Bass" setting that much, but the "Jazz", "Country", and "Electric Guitar" settings work really nicely! The manual is short, but adequate for helping you know what to do.

The only thing I'll be doing to make this easier to use is to apply a little white paint to the notches that indicate where the knobs are pointed so I can see from a distance. Even though it would be a bit ugly, I think glow-in-the-dark plastic knobs with a black dot position indicator would be more useful. At least you'd be able to see where things are pointed on a dark stage for a while.

To be honest, it would be totally worth it to buy three of these to have three presets and chain them together.

I am truly impressed with this $30 wonder! I haven't tried it direct on stage, but it makes my amp sound very good. I've got a Carvin RC210/115 combo which is a good soudning amp, but a bit sterile because it's truly just solid-state. The ADI21 gives my bass a thick tubey sound on both the "Jazz" and "Country" settings, and an agressive sound when set to "Electric Guitar". The unit is very quiet - much quieter than the BDI21 for bass.

I've only owned it for one day, so I can't speak for reliability. It is made of plastic with a plastic foot switch. Just a light tap of your foot is all it takes to turn it on, and unless you're switching between one of these foot pedals to another it really should stay on all the time. I'm not worried about using it on stage, but then I don't jump or run around while I'm playing. If you have a tendency to trip on your pedals or stomp on them this isn't the pedal for you.

Never had to contact Behringer, but I've heard it's a challenge.

I play rock, classic rock, and contemporary Christian. I play on one of the worship teams for my church. This will make it possible for me to get great sounds in a short period of time and will be very portable.

I love the sound I can get from the ADI21! I would prefer it to be made of metal with a metal switch, and would pay $60 for it if it were. It's okay made of plastic, but I can see it wearing out fairly soon.

I do think this is a stunning buy for $30, and if you're careful it should work for you a long time.

It does what you expect it to do. The EQ is fairly easy to use, but there's no markings for reference.

The "blend" modelling effect supposedly makes your piezo pickup soudn like the signal from a condenser mic through a tube pre-amp, and it does a good enough job of warming it up- it apears to be a combination of EQ and a little compression. Beware you need to set this control before tweaking the EQ as it makes it very warm in the lo-mid area.

I play acoustic guitar in a number of lineups, am just starting to use mandolin. Both my acoustics are fitted with Artec magnetic soundhole pickups and cheap under-saddle piezos wired up in stereo. The mandolin has a passive piezo bridge. I normally go straight into the PA.

The ADI 121 does a good job warming up the sound from the piezo pickup . Unfortunately it can't handle the output from a magnetic pickup and clips horribly, so I only use the EQ/ effect when playing with the piezos only.

Otherwise I just leave it on bypass and use it as a passive DI box. It has a ground lift and phase reverse switch which is useful.

It eats batteries and the sound degrades really quickly when the battery's low. I must get a power supply.

Other than that, haven't had any problems, yet.

I gig with it without a backup, though not using the actual effect, just as a DI.

Never had to deal with the company.

I've been playing acoustics in a variety of styles, trad folk, jazz, acoustic rock to contemporary singer-songwriter.

I decided to get a pre-amp/ DI box so I could have control over EQ and levels on stage. Having looked at more expensive options I thought I'd give this a go first.

It does its job, which is to stop cheap piezo pickups sounding like broken glass. The lack of markings on the EQ knobs, or ability to use different input levels is a drawback, but at this price, I can't really complain.

I'll most likely upgrade to something more professional like a Fishman or Baggs pre-amp, but would keep this as a spare or for a second instrument.

Very easy. A little experimenting with the knobs will show you what it can do.

I run an acoustic guitar into this straight to a mixer for recording at home. It works quite well. I have the ZOOM acoustic (504 I think it's called) as well and the Behringer is actually quieter and easier to set. The ZOOM is good for effects, but this is good for just straight clean recording. The "effect" with the Behringer is controlled by the "BLEND" knob, which definitely colors the sound, which it is supposed to do. Sounds good. I think it's supposed to be a mic SIM, which is interesting. Sounds better than going direct without it, once I found some settings I liked. With "BLEND" on mild settings it can be just an EQ or DI box. But I like the "BLEND" feature a lot.

Clean and easy. I'm not super picky about acoustic tones, but I wouldn't use it if it sounded bad, obviously. Better than the ZOOM, which is good for drastic effects, but the Behringer is great for clean recording especially in a basic home studio.

Don't know. Seems sturdier than most anything else in its price range. More heavy duty than I would have thought.

Never tried them.

I like it. Perfect for the price. Doesn't do a whole lot but it's a great idea for direct recording. I like the extra control over the tone and EQ.

I guess I have a lot of home recording stuff. This is better than most cheap stuff, no complaints for the price. The mid sweep is cool. The effect is interesting, the BLEND works well. The effect itself is more imposing than I would've thought, but I like it now that I'm used to it, and the BLEND feature makes it easy to reel in. The XLR output is a quite cool too.

I compared it to the ZOOM acoustic pedal. The ZOOM is a little hissy and kind of a pain to edit, but has special effects like delay, chorus etc that the Behringer doesn't have. I like the ZOOM but the Behringer is better for straight up clean recording. Much easier to edit too. With the Behringer I found a sweet spot and rarely change it now, except the overall level control, you know.

Like someone else mentioned, a phantom power option would be cool. I can't find the manual (whoops) but I guess you need a wall wart. I bet it uses batteries fast, but haven't tried. Maybe not. The phantom power thing isn't necessary. Actually it would probably shorten the life of something like this that's priced so low. I think the SansAmp version might have it though. They make good products too, if you're looking to shell out more money. For the price the Behringer version is nice.

I tried it with a semi hollow electric and it was ok, kind of interesting but does not take the place of an amplifier IMO. I might try the "GI" version for that. This works very well with acoustic guitars with pickups though.

I guess it helps me make music. It's handy and easy and works as advertised. And inexpensive. A compression control would be even more useful. The "pad" is good to have. I haven't had use for the "lift" feature yet, but it's a good idea too. If you could mix this with the ZOOM and retain the quality without the ZOOM hiss it'd be perfect. But nothing does everything perfectly once you add too many features. And if it does it's much more expensive. The price is great. I didn't really need this, but had to try for the little it costs. I always use it now. This is good for what it does. Lot of bang for the buck. I'd buy another.

A breeze to set up and to get a decent sound from my acoustic guitars ans even a very nice jazzy tone from my electric guitar (Ibanez archtop). The manual is very short but a small complaint is that you have to figure out the marks for the settings. (a dot would have been nice on the pedal but also in the manual!!)

I use ADI live on stage ( just plugging it into the housemixer) for my acoustic guitar (seagull artist with Dean Markley Sweet Spot). The Sweet Spot asks for a preamp to get a nice acoustic sound from it. Nice feature is the para mid to get things right.
At home I use it connected to the mixer and into studio monitors with a subwoofer and the sound is awesome. (just add some reverb)

It seems you can depend on it but you have to use a Boss-style adaptor (eats batteries) and not an electronic one, so beware.

They emailed me the same day, so no problem

We do a kind a folky style with 2 acoustic guitars and bass. It was one of the best investments I did. I've been playing for 10 years now. I would buy this item again if it were stolen. I even consider to buy a second one, just in case.

Pretty easy, the label on each knob pretty much says it all. It could do with a white mark on the knob to show where it is pointing though...

Im actually running my electric violin through it, then into a laney t100 amp. It does a great job of warming up the tone, giving it a much more acoustic sound without the slightly harsh tone that it can sometimes get.

Ive gigged with it a few times, once i put a decent power supply into it its worked fine every time. Havent tried it with only the battery.

N/A

Overall it does exactly what i wanted it to do with a price to match. It gives a much more authentic violin sound than just the violin by itself. I stil need the reverb from my amp to help with the tone, but i never expected it to do that.

Pretty straight forward... refered to the recommended settings in the 'manual' (Actually just a piece of paper)

I bought this to improve my acoustic guitar recording... and I was disappointed. The recording sounded muddy, I tied all settings but unable to get a usuable tone... it also distort very easily... have to keep my guitar output way down...

but after refering to reviews of the Tech-21 Acoustic DI... the ADI21 performances seems to be on par with what is complain in the Tech21 review...

I think they are more usable for live use rather than recording purposes for acoustic guitar.

However, I do find one thing the ADI21 is good at for recording... electric guitar! I plug in my LP copy to get a jazzy tone through the ADI21, and I got a really impressive solid classic jaze tone out from the ADI21... truly imazing...! :) I have never heard my guitar sounded so good....

So for recording purposes, here's how I rate it:
acoustic guitar: 3
clean electric: 10

its made of tough plastic and seems durable...

but the main footswitch looks lame and weak... I would wanna step on it too much....

other than for recording acoustic guitar, I highly recommend this... but for live, use it as DI and leave it alone would be fine... don't step on it....

Great job Behringer!

This thing is pretty simple to operate. The fun is trying to dial in the tone you want with the MID/MID FREQ combinations. You can get a good, natural tone from your guitar. I use a Yamaha SLG-100S, so this is all the preamp I need before I send it (via XLR) to the board. Quick setup!

My only complaint is the amount of gain this pedal can generate. I have to be very careful not to overload the pedal with my Yamaha SLG-100S. I run at midpoint volume-wise on my guitar, and let the ADI21 do the rest. Really sounds great live! I have samples if you are curious.

I have only gigged with it for about 6 weeks. It is in my pedal board, so I don't expect any problems. It is a plastic casing, so I can't give a 10 for that. This pedal DOES EAT batteries. Get a power adapter.

Never dealt with them.

Overall, this pedal is a great value. I does everything I need to have it do. It provides a great gain structure with flexible EQ options. I really makes my guitar sound great through the soundboard of our band. I have used it 6 weekends in a row now without any problems. For the price, I would buy another one if this was stolen or broken!

Quick follow-up
I have used it for loud playing, and it amazes me how smooth and warm my low-level ovation copy sounds with the adi21.
The mid eq is very useful against feedback but don't believe in SantaClaus...
Still, I can play way loud without problem if I stand away from my amp.
Of course the eq lacks definition but since it is very useful along with the blend knob(always full on) to smoothen the harsh piezo tone I don't care at all.
If you want to pay 10 times the price to get the original, be my guest but a cheap guitar means you can't afford the tech21...
That's exactly where Behringer gets it right!
A cheap piezo guitar and this unit sounds way good...

This product is very easy to use. Basically, it's a fairly simple product with self-explanatory switches and knobs.

THe only gripe I have, like the reviewer below, is that the knobs are ambiguous about where they are facing. They need a dot or some other indicator so you can tell where they are pointing. A dob of paint will do for me, but this is probably something that should be added at the factory.

I had low expectations for this unit, seeing as it was so cheap. I ordered it just out of curiosity, to see what behringer's pedals are like. (I have a behringer eq and mixer).

I guess I was mainly after the ground loop elimination and mid frequency band. I didn't even know the unit had some type of internal processing. (whether it is digital tube emulation or analog.. i'm not sure).

I run a rainsong JM1000 into this. The rainsong has fishman electronics, which are a bit quacky in terms of the piezo end. This unit warms up the fishman very nicely. There's a noticeable difference in sound quality. My friend uses an ovation into his, and it does the same.

I've also tried this with electric guitars. If you are careful about the input level, you can get a decent clean sound. Suitable for jazz. The input is a bit impedance sensitive though, so if you go full bore into it with magnetic pickups, you'll get distortion. We've used two of these live in jazz gigs to great effect. (normally I use an evans preamp, but these pedals are really portable for those occasions when you don't want to lug a rack around).

I give it a 9 for quality in this area because its price/performance ratio is so staggeringly good. I'm sure it wouldn't compete against a rackmount acoustic preamp, but that's not what the unit is trying to do.

I have used it without a backup. It seems very robust to me. Very robust indeed.

Never

This thing is a bit of a steal. It is solid, and does a nice job of warming up acoustic guitars. The midshift is very useful. I haven't used the XLR output yet, though.

I've been playing for 10 years. Semi-pro jazz guy. I use jackson USA electrics (swee-tones and SLSes), a rainsong, a hofner john stowell, a couple of godins, and a ramirez classical. I play gigs every couple of weeks.

I've been running this into a graphic eq, then into a lexicon reverb unit and out into a power amp. I've gotten good results. my friend has a custom electric guitar (neckthrough) which sounds amazing with this unit. I can't duplicate his sound, even though my main swee-tone has the same pickups on it. Hmm.

Highly recommended. I'm glad I bought this.

This is basically a copy of Sansamp Acoustic DI. Three band equalizer with parametric mids, output level and a blend control to dial-in tube emulation as much or as little as you want. The manual is brief but adequate with a few samples - same samples as Tech 21.

My only gripe is that, it is impossible to see where the pots point at at dark.

It would also be nice to have it phantom powered.

One other thing is that, it consumes 25mA which is a lot. It probably eats batteries like hell but I'm using an adaptor.

I play bass guitar. I also have Sansamp Bass Driver DI, but so many bassists praised Acoustic DI so I wanted to have one. Tech 21 is expensive (though it's worth every penny) so I decided to try out this copy.

For a bass guitar the useful range is limited, but when dialed in it sounds great (I basically use the sample from manual with a little treble added). It is a rounded, more like an old-school bass guitar sound. It is also a lot more friendly with effects than Bass Driver DI. ADI21 lacks a drive control, but if you crank it, it can be overdriven. However, if you like overdriven bass I suggest either to use Bass Driver DI or put a distortion/overdrive pedal in front of ADI21.

It is as noisy as a bass amp, no more no less.

Since I bought my Bass Driver DI, I stopped using my bass amp. With ADI21 also, I go direct to mixer. My chain is bass -> Tech 21 Bass Compactor -> Zoom 3000B Bass Processor -> ADI21 -> Mixer.

Too early to tell. It's made of plastic which is not a problem, I used plastic boxes before. The suspect is the on/off switch. It doesn't look like the stomp switches I'm familiar with, but it seems to get the job done. But this is a preamp, you don't stomp on it too often. Time will be the real judge.

Having said that; I have other Behringer products and not one of them died on me.

Behringer has a huge website with a lot of information. Once I sent them an e-mail with a question and they've responded in time.

Overall I'm pretty happy with my purchase. If it were lost I would definitely buy another. Compared to Tech 21 Bass Driver DI, its range for bass guitar is limited but luckily it's the sound I'm looking for; well rounded. For the time being it replaced my Bass Driver DI.

I wish it accepted phantom power and it had knobs that I could see in the dark.

Very simple to use. Well rounded and quiet. Took away all piezo quack,but can be blended to put some in if it is part of your sound.

Martin OCX, Peavey Ecoustic to either a Roland DB500, Behringer 200 watt powered mixer, or board into full size PA. Quiet at all settings.

Buy two, they are dirt cheap compared to everything else...I know, I've tried a bunch of them. Time is the test

I've never had a problem with any Behringer equipment ever. So I cannot say how the customer support is.

Fantastic value is it. Play acoustic pop covers as a solo and duo act. Breaking strings for about 30 years. The gear list is short, but I've tried on alot of gear. The current rig is a Peavey Ecoustic, Sabine stick on tuner, a Dearmond Gold foil (Stratotone Jupiter Pickup) installed at the neck, bronze strings. Acoustic side is stock, dearmond is routed through an on board EMG BTS sytem and then through a wireless to a Tech 21 tri AC before the board. Pan pedal allows blended tones, all electric or all acoustic. Great rig and very cheap. This piece removes the last rack mount preamp gear and puts me into 3 - 9 volt batteries to carry in and out. I love it. I've tried all kinds of acoustic preamps...Tech 21, Boss, Fishman etc. etc. and this is the best bang for the buck for me. Plugged in at the bar, no one cares but you how it sounds. Would I use it to record? I don't record so it doesn't bother me. Incredible value, designed in Germany, built in China and shipped to Boston with a battery for $30. Absolutely Amazing.

The only guitar that has come close to this is a Citron AEG. The Peavey was less than $200 and is easily replacable.

I have only had it a few days. I was able to get a sound I liked by sampling out the sample sounds in the manual.

I used it through a Gibson Chet Atkins SST and it clearly improved my sound right away. It is quiet. It took the trebly sound away from the guitar quite well. It is a little of a muffled sound and it is distorting the sound a little but I may be able to improve that once I start tinkering a little more with the adjustments. I am quite pleased overall considering what I paid for it.

I am pleased with it as a way to improve the sound of the SST. I tried it with an electric guitar and it was ok but not as good. It is an acoustic DI so this makes sense but they do recommend you try it on electric guitars, keyboards and such. Haven't tried it with the keyboard yet but I plan to.

Easy enough to get a good sound out of this if you know the Sansamp Acoustic DI, which it seems to be a thinly veiled redesign of. If you're not familiar with that device you might have some troubles.

This is a microphone simulator. In other words, it is supposed to take a saddle pickup input, and make the output sound like it was done through a microphone. So it has other uses besides cutting the harshness of a piezo pickup. I use it on electric guitars too, after other analog modeling pedals, to simulate some power amp sag. I've tried the Tech 21 original after a Line 6 Pod as well, and it was nicer to my ear than the built-in cab/mic simulation.

Seems to give a nice sound. It reduces harshness like the Sansamp Acoustic DI. Plus . . . it has better headroom. The latest batches of the Sansamp Acoustic DI I use have had horrible headroom when operating on batteries. The ADI21 will take a hotter signal before distorting.

Can't say as it's brand new. I purchased it as a cheap backup to my Sansamp Acoustic DI, to keep in my instrument case for jams, but I like the ADI21 better. However the ADI21 is plastic. Damn heavy plastic, mind you, but plastic nonetheless, and the pedal button does not make me comfortable.

Can't say as I've never had to test this. I always have another similar device at hand in case of emergency. If I end up really liking these I'll purchase one or two more, they're that cheap.

In an audio sense, works better than the device that inspired it for my applications. In a construction sense, it's not as rugged. The pots are lots looser and easier to knock out of position, it has a pedal button for activation instead of a switch, and is made of plastic.

I just received this, played an hour with it so far.
Go to the behringer site for the specs, I only share my first impressions now.
Because you all wants to know: shall I buy it?
Analog box, way easy to use of course.
Good manual, if you ever need it.
I tested it with 1) Artcore Setzer-style Ibanez, 2 humbuckers
2) Yamaha AEX1500, pro-level jazz axe with piezo/active preamp.

Let it be very clear: the Adi21 doesn't work well with the Artcore, except if you turn down the output level of the guitar to 4-5. Must be impedance mismatch, but no problem when doing so.
With full output on your HH guitar you only get nasty clipping.

With the yamaha, no impedance mismatch hence clear sound while far louder than the passive Artcore...

First, it does its job, which is to smoothen the piezo harshness. And helps a lot with the parametric mid as a notch filter.
Of course my yamaha sounds way clearer straight in the p-a, but the Adi21 is a great help when playing a bit loud. So are the deals in music amplification...
I must say my yamaha sounds way better than almost any piezo-equipped guitar (hey, I payed for that!) so chances are that you'll only get the benefits of the Adi21 with your guitar.
I'll post when tested with a standard electro acoustic.

So are my first impressions: a good thing to have in your set-up.
Useful against feedback and piezo harshness.
Be careful with the output level of your passive jazz axe.
Thanks for reading, hope this helps