DigiTech GSP-21

This is a straight forward multi-effects unit that I bought off eBay a couple of years ago after hearing a friend using one in his rig.

It is very easy to program, but it helped a great deal to actually read the manual (downloaded off the Digitech website) as it gave me a better insight in how to use it.

My unit is one of the originals that date back to 1991...

I use it in the effects loop of my Pod XT Pro to give me a multitude of options that the XT Pro doesn't offer. It also seems to tighten up the tone and give it an analog edge while removing some of the digital artifacts present in the XT Pro, which is present in ALL digital modelers a.k.a. fuzz.

The effects can go from transparent to completly crazy depending on how you tweak the unit, I especially like the chorus, tap-delay and speaker simulator but all of the effects are very usable and can be tweaked accordingly.


Couldn't go back to using the Pod XT Pro without it now!

Well-built and has never had a glitch yet after almost 3 years.

Digitech was very helpful when I called and the website did have the manual available.

I've been playing hard rock/metal professionally for almost 20 years and this unit is a must have for my needs. Coupled with my fulltone/love pedal/BJFE/Zvex pedals in the front, Pod XT Pro in between I can nail ANY guitarist rig ever imagined.

If you want thick, saturated post-pre effects this unit will keep you busy & happy for a long time...

This is the best rack effects unit to nail grunge rock without sticking a bunch of pedals on the stage!

Smokin' easy to edit with tons of options, including speaker sims and compression that's good enough to use for vocal-insert recording (which I have done in a pinch for scratch-tracks and it sounded better than a vocal unit I'd been using).

Mine's all original from 1991 and has stayed in my rig longer than the 2101 and GSP-21 Pro I bought after it...

I've used this in the effectx loops of so many amps I can hardly recall, but for sure I've had it in my Triple-Rect, Roadstar, Marshall JMP-1 & my Demeter TGP3 and with a few tweaks on the effects loop levels it delivers lush sweet time-based effects (chorus/flange/delay/reverb), modern/vintage distortion/fuzz when tweaked properly and can make a single 4X12 sound like a wall of full stacks! The noise-gate removes what little noise the unit adds, which is next to nothing since I don't push the gain levels, and even cleans-up the noise from the amp.

The only drawback is the bypass is unusable, but I never use it anyways so no matter to me - Why would you bypass this monster anyways?

Built like a tank, the only issues I've had was with dirty switches in the foot-control that always cleaned right-up after getting a shot of electrical contact cleaner.

Sounds the same as the day I bought it...

Never needed them for this unit, but on other stuff they've been very friendly and helpful...

No unit produces a thicker grunge effects pallette in an amp's effectx loop than the GSP-21, a little time tweaking and you can get some swirly, psychodelic, screamin' patches that would make Kurt Cobain jump off the stage!

A real head turner...

I've been using this unit since 1990. Used it five to seven nights a week live for years. Pretty steep learning curve at first but now is second nature. Manual was/is sketchy, but Digitech explained that they want people to use their ears to develop their own sounds. Have it MIDI'd to Roland GR-50 so I never used the pedal.

Use this with a Strat with DiMarzio Virtual Vintage pickups. Usually run it into an ADA microcab direct to the board. Sound quality is good overall. Versatility is the point of any multi- effect unit. Doesn't do any particular sound perfectly, but can cover a lot of sonic territory. Good chorus and delay, reverbs are okay and does sustaining distortion better than slight overdrive.

Used it constantly. The only problem that I ever had was a loose battery connection that dropped all of the pre-sets. The battery is an unusual size, so beware. Otherwise, ultra-reliable.

Dealt with the techs quite a bit, but I was working at a retail store. They were extremely knowledgeable and helpful.

I have had an on-going love/hate relationship with the unit. I play professionally and cover many styles. The unit does the variety very well, but there is still no substitute for a great amp with a mic. Unfortunately it isn't always practical in live situations, especially at low volume. This unit is a life saver in my particular situation. I have spent a lot of time programming and tweaking the sounds and they work well for me. It is like any product in the fact that it is only a tool. If you have a basic understanding of how sounds are created you can get a close approximation with this unit. I would purchase again.

At first it was intimidating to use... in 1991 and me being just a guitar player... later on I got used to it. Eventually I knew it backwards and forwards.

Personally I grew disenchanted with this unit very early on. Thru a decent amp it wasn't too bad, but through my Peavey Bandit it tended to suck. Later I was running it though a Fender M-80 solid state half stack and it sounded a bit better.

In general I found that the tones were lackluster, tended towards over-effected sounding to get a thick tone, very strident and brittle. Overall I thought it really spanked.

Never gave me a problem, but I imagine it eventually would like all digital gear.

This was the first thing I bought when I got out of boot camp from the Navy in April of 1991 and these were brand new. I demo'd it in the store and bought it. I had originally gone there to buy a Marshall JCM 900! Man, was I a stupid bastard!

My idea was I wanted to build a portable 4 track recording studio (am I taking you back in time yet?) that I could take with me from duty station to duty station. I had a drum machine, guitars, Peavey Bandit, and the 4 track; what I wanted was to get some really good tones.

I figured that it would be hard to carry around a JCM 900 head and a Peavey Bandit (until I got a 1960 slant 4x12 that is) in the military so I got the Digitech instead. I figured I could record *DIRECT* and not have a problem.

Oh man... I threw away all those demos because they sounded so wretched!

Later on--still not learning my lesson--I bought a GSP 2101 and was a little more satisfied with it but what I needed to do was buy a real amplifier and quit pussyfooting around.

But, I was a sucker for TONS OF FX at my fingertips. Now I hardly use effects and when I do it is all vintage analog stuff like Small Clones, Phase 90's, DS-1's and so forth.

If you can find it cheap it may provide some interesting FX in an industrial deconstructive sense, but for good guitar tone this thing will make the most pristine amps sound crappy. It really blows.

VERY EASY TO USE ......EXCEPT FOR MIDI .....CAN'T SEEM TO GET THE MIDI TO WORK......NEED MANUAL ......IF YOU HAVE ONE......PLEASE HOOK -ME - UP..........

SOUND IS OKAY..NEEDS TO BE TWEAKED IN EVERY WAY...DISTORTION SUCKS..

GOT THIS UNIT FROM SOMEONE WHO CLAIMED IT DID NOT WORK.IT WORKS NOW...

WAITING ON MANUAL ...WE WILL SEE ...DOUBTFULL I WILL EVER GET IT.

ART'S SGX 2000 MUCH MORE CONFUSING .........

Fairly easy to use, very much plug and play. I don't have the owners manual, and will never need it. That explains it all.

Sound quality is great if you can get by all the noice that goes through this thing. I've had nothing but problems with trying to get rid of the squeeky ear renching sounds that the thing puts out. The only way to solve this problem is to throw it away and buy a boss GT5 wich is exactly what I did!!!

This thing crapped out on me about 6 months ago and I have been trying to find someone to fix it. I cant sell it when its not working. Never depend on it and always take a backup!!!!!!!!!

Don't even try!!!

I think that this thing is a lot of fun. I love the foot pedal and all the sounds. Its simple, sounds cool, and has some neet fetures. I just wish it worked properly. Aside from the noise that it blares its not a bad processor, if someone gives it to you. I wouldn't give over 10 bucks for one its not worth the hassle or the money.

esay to edit and use
have no manual, dont need one
I will check firmware level

Strat
Unit is noisy
distorton poor, chorus good/v good
delay ok, no tap tempo?
noisy, and gate chops

just bought it for $100USD
needs cable for footswitch

no opinion

for $100, seems okay. The swirling delays w/chorus were cool. Leslie very cool, with lfo and other tweaks

depening what type of sound your looking for, the gsp 21 is perfect for your medium to semi-pro musician.the distortion settings vary but are easly manipulated.the only problem i've experienced is when jammin with another guitarist ,after a certain volume( decibles) you loose all high ends .

I've personally have been jammin,giggin,recordin,an just plain ol' rocking ass with this baby and never ever had a back-up unit,or needed one.A true war horse.Just take care of it, and it will last a long time. had the GSP-21 for 8.5 years and it still serves the purpose.

Just plug it in and the factory presets will rock your socks off. The editing patches are easy to understand if you sit down with it for a few minutes or so and fool with it. No manual for it however.

You can get any kind of sound you want out of this thing. Except a wah sound. I use a USA Strat a Mexico Strat, Les Paul Studio, Usa Telecaster, and a Kramer Striker. As afr as amps I use a Fender Twin and a Marshall JCM 900 stack and it sounds great. It can be noisy if you dont set it up to not be noisy. The effects sound great just dont use the volume knob on the guitar use the amp volume it dampens the notes. I can get a real deep fuzz type distortion out of it to a crisp loud rock hard distortion. All effects on it are very good.

Yes you can depend on it as long as you use top grade guitar cables it eats those cheap ones for lunch. I use it on lots of gigs I have two of them a GSP-21 and a GSP-21 PRO.

I deal with an electronics company for repair and yes they do drop dead on you every couple of years. But most of the time it only cost around $100.00 to fix it.

Blues, Rock.
17 years
I would cry!
I love its effects and hate its looks.
I once had a Rocktron Camillion On-line that thing was nothing next to this thing. sold that Rocktron and bought me another one.
You cant find to many of them as they dont make the GSP-21 anymore so used is all you will find I have tried the GSP-2101 and it was ok but kinda big for the unit space I needed. I wish it had Wah but a crybaby took care of that. I use it in every song I play no matter who or what I jam to. It is capable of doing anything and sounding like anyone Hendrix, Vaughn, Santana... and many more.

Takes some getting used to, but once you get familiar with the set up it's not so bad. Need to be programming minded. You can't just turn knobs until it sounds good (unfortunatly.) This is a rack mount box with quite a lot in it, so it takes a little time to learn how to use it.

When I was using this it was with a mexico telecaster into an old traynor reverbmaster amp. They played nice, which isn't always the case with effects through this amp. There is really only like one good distortion in it, and that is after you tweak the eq. The reverbs and delay/flange/chorous effects are great though. Very lush, with lots of control to shape you sound. The eq is pretty good. The multi-tap delays are really fun, although you need to learn how to use multi-tap delay before you even try to use it with a band. The only annoying thing about it is the damn noise gate. You can turn it down, but not off. Whenever the gate cuts your signal you get an annoying fuzzy pop sound. Besides, I like the hum. Lets my know my guitar it alive.

I bought it used from a friend of mine who used it for 5 years with no problems. I haven't had a problem with it yet, althoug I don't really use it any more. No need since I got my Boogie!!

Never delt with them for this box.

There are a lot of cool things in this box. The distortion is not to my preference although I was ablt to get a distortion I could live with out of it. The other effects are great. I don't use the compression at all cos I just don't see the point of compression, and the chourous/flange/delays/reverbs/eq's sound good. There is a built in speaker simulator, great for going straight into a 4-track (which is all I really use it for now)...the noise gate sucks. Why can't you turn it off? I don't get it. But that is really my only gripe about it.

Use a good preamp and put the digitech in the effects loop and you instantly find 50 good sounds (switch off all distortions). You need to read the manual to edit but, it's pretty straight forward. I have the original GSP-21 bought in 1991. Rotary encoders didn't exist in '91 but, if they did installed in this unit I would change my rating to a 9.
The footcontroller was designed by the gods.

PRS, Carvin, & Heartfield guitars; Carvin Quad-X tube preamp; Carvin FET 450 power amp. There are two ways to use the GSP: as a preamp or as an effects processor. Don't use it as a preamp. It's 1999 now there is way better stuff for the same $620 (1991) price tag. As an effects processor ($150-250 used) it's pretty good still. I mean look I still use it. There's no harmonizer and no wah everything else is included and all at the same time if you want.

Yes it is RELIABLE!! 8 years and not a problem yet.

I've never had to deal with them so I don't know. All I see is that they keep on producing more innovative stuff at the right prices.

I play all styles and it matches fine, I just bought a Zoom GFX707 that has everything the GSP21 has plus wah and a pitchshifter. I run the Zoom straight into the power amp in of my Fender Deluxe 85 and BOOM mini terror rig. I've been playing 10 yrs. If my GSP-21 were lost or stolen I'd get a...I still don't know otherwise I would have bought it already. Something with a foot controller and is versatile. Hey if you can find one for less than $200 bucks get it, I mean you'd need compressor, delay, chorus/flanger, distortion, and EQ pedals to do the same things.

It is pretty straight forward and not too hard to get sounding good, but it isn't fast to program. The methods of stepping through each setting are not particuarly quick and easy. Things like Ultra Reverb are quite complicated to get a good sound from, but the simple reverbs are easy to use.

I started using this by itself plugged into a home made amp using a Samick Strat. The distortions weren't too bad, but I'd say they aren't the best features. I currently use a Custom made guitar in a Jackson/Ibanez style with DiMarzio Evolution pickups, and a JMP-1 for all the distortion. So I don't use the compressor or distortion. The delay is pretty good, so is the reverb. They are the main things. I haven't a lot to compare the chorus and flanger with but they seem sound okay to me. The seven-band EQ is pretty good, better than some of the similar age ones that only had 3-band. There is a little noise produced and the noise gate can cut this out, but tends to kill the attack on the sound and even without the noise gate on the unit can often leave a low volume cut-off on the sound, instead of letting your sound fade away nicely. That is my major complaint. Apart from that, it doesn't have many of the effects of the newer units, but if all you need is EQ, Flange, Chorus, Delay and Reverb, along with the noise gate, distortion and compressor, it will do the job.

I've owned it for about 4 years and never had a problem with it.

Never dealt with them.

As I said, as the sound fades out it won't fade the whole way, when it reaches a certain point it often just cuts out which is an annoyance. Apart from that it sounds fine for everything from blues/jazz through to heavy metal. I personally don't get into solid state distortions, but the ones one this aren't that bad, especially when you consider the age. Doesn't have many of the effects of the newer effects units

I find it straightforward to use, although the panel layout can be a little confusing with two identical sets of cursors side by side- occasionally I'll spend ages programming a patch, then accidentally change patches when I mean to change a value, and have to start again (I know, I'm unco). The manual is a little skimpy regarding some issues, particularly MIDI functionality.

I do techno, and my GSP is effectively a studio-only instrument. Guitar amps are fairly noisy anyway, which is probably why Digitech figured they could get away with the shocking signal-to-noise. There are really too many gain stages (VCAs) in the signal path, but if you fiddle around enough the problem can be minimized. Generally the effects are good- they are quirky, and unpredictable at times, which I like. I find that the VCAs overload easily, which makes getting sufficient dynamic range more difficult.

Mine came with a remote footswitch pedalboard and a long cable (is this standard?) which I have no use for. I'm not a guitarist, but I imagine the GSP-21 would be a nightmare live- it is noisy, unpredictabe, and sends out earsplitting peak signals whenever you switch on or off certain effect stages or change patches. Moreover, mine is old- god knows what sort of life it had before I acquired it- and it's screen module forgets how to spell and starts generating random characters on-screen unless you give it a few hours to get up to operating temperature after turning it on.

As an electronic musician who doesn't use a computer, I find the machine valuable for "rinsing", or sound-design. It is quirky, and capable of turning the most bland arpeggiator riff into a total Tangerine-Dream ambient halcyon wig-out- Future Sound Of London eat your heart out. However, I do a lot of stereo track-bouncing using a digital MTR, and the unit's signal to noise problem restricts how many separate wet overdubs I can do using the GSP-21 before the background noise piles up too high. Overall- its good shit, but I have to say that when it craps out on me for the last time- and that may be soon, given its dodginess- I won't be hunting for a direct replacement.