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RP21D Review
RP21D Specifications
Software

About this site

The RP21D is a guitar preamp processor made by Digitech. This site is intended to share knowledge about the RP21D. The owner of this site is not related to Digitech.

Alex Garibay <visualdj> RP21D Review

The programming is divided in two main sections:
Preamp and Effects.

The Preamp gives you access to the next modules:
Compressor -> Analog Wah -> Tube distorsion -> Tube distorsion EQ -> Solid state distortion -> Solid state distortion EQ -> Noise Gate
You can bypass any module, and you can mix the two distorsions making some very good sounds.
Each module has its own parameters, making they very "tweakable". One great feature about the two distorsions paths is the morphing capability which enables you to switch the distorsions with the expression pedal. For example you could be using some grunge solid state distortion and change it to a bright clean tube distortion with the expression pedal. And the unit does it very smoothly.
You can save almost any configuration in the modules, for example, if you make a great tube distortion you can save it, and if you make a great preamp configuration you can save it too. Also the RP21D comes with 30 factory preamp settings, and gives you room to another 30 user preamp settings.

The Effects section is very big. You have a lot of digital effects, but what I think is the most important to know about this section, is the configuration of the effects. The configuration determines how the signal is routed from module to module, and the processing power allocated to each effect. You have 15 different configurations, and you can use up to 4 effect modules. The modules can be set up in series (8 config.), parallel (4 config.), split parallel (1 config.) and parallel/split (2 config.) configurations, and the effects (module effects) can be placed in any order. Also, the configuration affects the morphing capability of the RP21D. Something that is stated in the user manual is the power processing of each module. If you use 4 effects each one would use 25% of the SDISC II processing power, and if you use only one it would use the full power of the SDISC II getting better control and fine tuned adjustments, and producing better sound results. When I read this I couldn't belive because I used the unit and I didn't notice the difference between a 25% and 100% module. I mean, I didn't hear any noticeable difference. What is good to know is that some module effects (whammy and harmonizer) use more processing power than other modules. So, you can get them only in some configurations, and not in everyone.

Each effect module has its own parameters. You have a lot of factory settings for each effect, and you also have room to save your own settings.

Something that I like a lot about the Digital Effects section are the equalizers effect modules (graphic and parametric). This effects give you a total tonal response over your sound. They are an excellent addition to the Digital Effects.

When you finish with the effects section you go to the master mix and the cabinet emulator. In the master mix you configure the dry and wet parameters. The cabinet emulator make your sound go from a high tone to a low sound.

The pedal asignment is excellent because you can asign any effect or preamp module to the pedals, and also, the expression pedal can be asigned to almost any parameter of the effect modules and preamp modules. Also, you can tweak the expresion pedal giving max and min ranges, pedal number, etc. And also, you can asign "modifiers" (Dynamic Filters, Low Frequency Oscillators LFO's, MIDI continuous controllers) to the parameters! I haven't used much of this, but the Dynamic Filters and the LFO's affect the effects response. For example, in the stereo chorus you have the deep parameter which has a range of 0 to 100%, using the LFO over this parameter makes it to oscillate between a range you give. The modifiers have its own parameters too.

Finally, if you want to store your presets, you have 128 user presets (128 factory, 128 user), and also you have the midi output/input and there are great software for store and edit presets (RPEdit, Digitech Updater Software). And there is the SPDIF Output (to the digital recording), input and output levels, headphones output jack, and the left and right outputs. The RP21D doesn't have effect loop send/return (arrg!!!)

My first processor effects was the ART ECC (8-7 year ago), and when I listened it first I was totally amazed, my guitar sounded amazing. Then I listened some other units through the time and I wasn't so amazed like the first time. But when I listened the RP21D I was amazed again. You can get very good sounds from this unit, good distorsions and good effects.

RP21D Specifications (take a look to the Official Digitech Site for the latest info)

INPUT SECTION

Connector 1/4" Unbalanced
Nominal Value -8 dBu
Maximum Level +10 dBu
Impedance 470k ohms

OUTPUT SECTION

Connector (2) 1/4" TRS Impedance Unbalanced
Nominal Level +4 dBu
Maximum Level +18 dBu
Impedance 50 ohms

DIGITAL SECTION

A/D Converter 20 bit 128 x Oversampled
D/A Converter 20 bit 128 x Oversampled
Sampling Rate 44.1 kHz
Output S/PDIF

DSP SECTION

Architecture Static-Dynamic Instruction Set Computer (S-DISC II™)
Digital Signal Path Width 24 bits (144.5 dB)
Internal Data Path 48 bits (289 dB)
Dynamic Delay Memory 256k x 24 bits (5.94 seconds)
Static Delay Memory 256 24-bit registers (6.55 milliseconds)
Data ALU Processing 10.0 MIPS
Address ALU Processing 15.0 MIPS
Multiplier Size 24 bits x 24 bits

GENERAL

Frequency Response 20 Hz to 20 kHz +0, -3 dB
S/N Ratio Greater than 90 dB: ref=max signal, 22 kHz measurement bandwidth
THD Less than 0.04% (1 kHz)
Tube 12AX7
Tube Plate Voltage 145 Volts
Factory Programs 128
User Programs 128
Dimensions 24" (w) x 8.25" (d) x 2.25" (h)
Net Weight 12 lbs
Shipping Weight 13.5 lbs

RP21D Software

Digitech RP21D Updater Software
With this software you can update to the 1.10 Operating System version, store and load presets, and store and load bulk data. It is very easy to use.

RPEdit (beta)
Store, load, edit, etc., your presets with this excellent free software from Bruce James. It also supports other Digitech units (2120 VGS, 2112 VGS, RP20, RP12, RP10, Valve FX). To use it you will need the Operating System Upgrade 1.10 from Digitech (Use the RP21D Updater Software).

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