DigiTech GSP2101

DigiTech GSP2101

serial#: 3862753
year: feb. '94


Multi effects system
2x 12AX7/ECC83 preamp tubes
over 70 different effects
18 bit AD/DA converter, 48kHz sampling freq.
Any effect can appear at any point in the signal path
Up to 10 parameters are realtime controllable
full control over signal path
PPC210 upgrade (doubles it's normal processing power)
Software 3.00.00
20 MHz

GSP2101 Patches
Audio Samples

page updated: February 15 2002


It's one of the most known preamp + effects units of the 90's. When I bought it, I first used it as a preamp as well as fx processor. But the preamp section is not all that, so I now only use it for fx. And for that, it is more than excellent. In fact it is one of the most versatile guitar fx unit ever made, only the Eventide products (which cost at least 2 or 3x times as much) and the latest Lexicon and TC Electronics products offer similar flexibility.

It is dead quiet and you have full control over every possible parameter and placing of the fx in signal path. That means you can fully choose your own effects combinations and the way you want to link them, no matter how complex. Want to put the reverb through a stereo chorus and then pitchshift the unchorused reverb?. No problem. And all in stereo!! (take a look at the Audio Samples, there is sample of an Old Synth sound I've made). After this one DigiTech made 2 other (similar) units, but non had the flexibility that this one had. That's why I love it so much. I don't care much for standard sounds, I want to have full control over everything. Yes I'm a control freak!.

Another great thing is that you can change all parameters (up to 10 at the time) realtime by using the midi switches and expression pedal(s) of the Control One midi controller . I use it to blend in delays, gradually change the EQ settings, change the depth or speed of the chorus, etc. You are truly limited by your own imagination.

I've used this as my main preamp for a long time, but I'm glad I've got the Mesa/Boogie Quad preamp now. The preamp sound of the 2101 is not very good. Although it uses tubes, there is not much dynamics or tone that is affiliated with sound of tubes. I guess they use the tubes primarily to color the sound and use op-amps to create the distortion, like Marshall does since the JCM900 amps. But changing the tubes has some effect on the sound. The stock tubes are very (read: extremely) poor Chinese ones. So I changed them for one Sovtek 12AX7WXT (for more high gain on the clean setting) and a Ruby ECC82 for less gain in the high gain mode. And this worked out pretty well. It gave the 2101 a better sound, but still not good. The preamp lacks definition, clarity, tone and dynamics. It always sounded like a big mush. While the Quad preamp has such a beautiful tone and no matter how much gain you use, you can always hear every single note.

Mine was one of the first versions of the GSP2101, they where produced for many years and after this one DigiTech also made the LE and Artist versions with upgraded software and some with the dual S-Discs (which doubles the amount of fx you can use at 1 time). Since I got it, it went from software 1.x to 3.0, changed the tubes, added the PPC210 card (to literally double it's power) and upgraded it from 10Mhz to 20Mhz. So it went from the slimmest version to the most advanced one DigiTech ever made. I now have the ability to have seamless program change. And I can make presets that are twice as large as a stock GSP2101 could make..... it's the ultimate machine.

Especially the seamless program change is cool. I can program how long the sound of the previous patch sounds through in the new patch. So if I have a patch with a lot of delay and reverb and switch to a new sound, the reverb and delay will fade out nicely while I play over the new preset. I've connected the GSP2101 midi out to the Nobels MS-8, which takes care of the channel switching of the Mesa/Boogie Quad preamp. The preamp always sends out a signal, so I designed a Custom A/B Switcher that lets me mute the signal when I only want to hear sounds coming from the Digitech. So now with just one touch of the button I can go from "clean + Accutronics reverb + eq + detune + chorus + delay", to "screaming lead + eq + (light) detune + noise gate"!. Without any audio drops or anything. My rig is really fully programmable and the GSP2101 takes care of it all. Man I love this machine..... It is far more flexible than any other device ever made by DigiTech.

I really like do to some wicked stuff with fx to create new atmospheres for which you would normally use synths. For example, listen to the Old Synth sample, it clearly shows the possibilities of the 2101. Lately I've been working on more of these kinda things and have come to great results. As soon as I have the time, I'll post some of these recordings online.

The fx send of the Mesa/Boogie Quad preamp goes to the input of the GSP2101. The fx send of the GSP2101 goes back to the Quad preamp, which means that only the analog section of the DigiTech touches my dry sound. The Quad sends a signal to the Behringer Ultralink Pro mixer, and the Digitech sends a stereo signal (through XLR connections) to the mixer with only the fx sounds. That way I leave the fx mixing over to a mixer, instead of the GSP2101, which robbed some of the signal quality. The only time that I use only the signal from the GSP2101 is when I need a synth like sound or when I need a noise gate (rarely). With the mixer added to the signal line both the dry and the fx sounds are much nicer and better of detail. So no need for newer fx processor. Although I will upgrade it eventually to a TC Electronic G-Force - for it's higher quality.

I use the GSP2101 primarily for delay, chorus/detune, EQ and noise gate, and of course MIDI control over my whole system (take a look at the pedalboard page for more info). But I've also made some synthesiser type sounds, that drastically change the guitar sound to something closer to a synth then a guitar. For reverb, I most of the time use the one of the Mesa/Boogie Quad preamp, which has 2 different, tube driven, Accutronics spring reverbs.

For those that use delays, check out my BPM / Delay Time Conversion page. It incluides all usefull delay times for rock music within 85 to 150 BPM, including triplets and 5over4 counts.

If you own a GSP2101 be sure to check out Dieter's GSP2101 page. He's a guru and he knows everything there is to know about the GSP2101. His website is amazing.

PATCHES: I've made some patches with the GSP2101 that are worth sharing, so here they are.

My latest design. It's large and pretty complex, but the result.... ahhh pure joy. With it you can create sounds similar (even better) then the Old Synth patch, but the great thing is that it's capable of endless and smooth sustain. You can add sounds to the soundscape, or just make one and play over it without affecting it. This is for all you Fripp lovers or for those who want to play the intro of Wish You Were Here from Pink Floyd, both the synth and solo at the same time!.

I'm really proud of this one. For me this is the best example to show that the DigiTech GSP2101 is by far (in it's price range) the best unit to make really strange stuff. It sounds really good and not at all as a guitar and doesn't use those annoying pitchshifters.

I use this one with my band. Just play single notes and fade them in with the expression pedal and you got a sound that's simply amazingly rich and full and will fill the whole room with it's stereo spread. I could sit in front of my speakers for hours and just listen to the amazing stereo sound.

I was looking for a cello-like sound and this one came close.... as far as possible. I use it a lot when we're jamming to just add a layer to the music. Really worth checking out.

I made this one just for fun, but does work. It enables you to out-stereo your sound!. It places the delay and detune outside your speakers. The concept is simple and is the same as the surround stuff from Behringer, JBL, etc. You just place the stereo signal out of phase on the opposite side and adjust the mix levels. It works really good with 2 tap stereo delays. But you should be careful with recordings because the phase shifting might give you more troubles then fun.

This one was made by P. Baker who owns a Leslie 147 and made a patch that comes REALLY close to a real Leslie. It involves modulation delays, high/low pass filters, tremolo's, panners and eq's. These are really all needed to get anywhere near a real Leslie sound. This is by far the best Leslie emulation I've heard in a long time. This is one of the few that uses different speeds for the horn and speaker!.

(take a look at the Audio Samples, there is sample of an Old Synth sound I've made, with only the GSP2101, that you gotta hear)


Related subjects

Audio samples
Mesa/Boogie Quad Preamp
Nobels MS-8
Custom A/B Switcher
19" Rack
Korg DTR-1 Tuner
Signal line
BPM / Delay Time Conversion page

DigiTech Homepage
Dieter's GSP2101 page , all there is to know can be found here.
TC Electronics Homepage

2003, MvH