Note: Despite the fact that this document has some noted changes in it (marked in blue), this information is outdated and should be regarded as potentially erroneous. CLP August 1996
GSP-2101 FAQ transferred to HTML by Curtis Pastor Aug 1996
GSP-2101 FAQ version 2.0 Dave Blevins ([email protected]) 6.2.95
FAQ REVISION HISTORY
11.23.94 - version 1.0 11.29 - 1.1: line length increase; minor formatting changes; Bulk Dump section added; Program Memory section added; enhanced explanation of "true stereo" operation. 11.29 - 1.2: updated Processor / Memory Upgrade section. 12.15 - 1.3: added reference to mailing list 1.4.95- 1.4: updated PPC-210 upgrade, firmware, foot controller, and Comments/Observations sections; added info on sys-ex document. 6.20 - 2.0: updated information per feedback from Digitech (Thanks Randy!) Affected sections: Analog, Global EQ, Foot Controller, Firmware, Limited Edition, Observations, Internet Resources. Also added new "Miscellaneous Questions, Answers, and Tips" section.
The Digitech GSP-2101 (list price $1099) is an analog/digital effects processor for the guitarist. This FAQ (Frequently Axed Questions document) will address aspects of the 2101 that are either not explained well or not mentioned at all in the manual.
ARCHITECTURE
The GSP-2101 consists of a completely analog section (with the exception of the digital-to-analog logic for parameter control) followed by a true stereo digital effects section.
ANALOG SECTION
The effect ordering in the analog section is fixed. From the mono guitar input, the signal passes through a compressor module, distortion module, and fourteen band EQ module (see below). The distortion module can be configured as either solid state or tube; the solid state mode is essentially that found in the GSP-21 and RP-10 with Overdrive, Heavy Sustain, and Grunge modes. The tube mode uses two 12AX7s and has three control parameters: Type (Clean, Distorted, and Saturated), Gain1, and Gain2.
GLOBAL EQ
The Analog EQ module is divided into two seven band equalizers; the first seven bands' settings are stored with each Program. The other seven bands are allocated to a Global EQ section - its settings do not change from program to program. This allows the user to configure the overall tonality of the 2101 for different amplification systems. Only one set of EQ parameters for this part of the module can be stored.
DIGITAL SECTION
The S-DISC processor-based digital section is very similar to a Digitech TSR-24. This portion of the GSP-2101 can be used standalone by bypassing the analog section. In this mode, it is a true stereo effects processor - i.e. it can maintain two independent signal paths from input to output. (As an example, Algorithm #8 is a stereo in / stereo out "Gigaverb" reverb.) Like the TSR-24, almost complete control over digital effect ordering is available to the user. Each "ordering" configuration is called an Algorithm. There are factory Algorithms that cannot be changed; in addition, a User Algorithm memory space is provided for customer Algorithms. Each of the 100 fixed and 100 User Programs are based on an Algorithm; the rest of the parameters of a Program pertain to the settings of each effect module that is a part of the Program's Algorithm. The 2101's operating system makes efforts to prevent the user from doing dumb things to Algorithms that are used in more than one Program.
The 2101 in its base configuration has 256 CPU blocks and 256 RAM blocks; the Owner's Manual includes a table of the _approximate_ number of blocks that each effect module takes. Emphasis should be placed on "approximate". You may think you have enough blocks left over to add, for instance, an MFX Reverb module to an Algorithm (based on adding up blocks used by the existing modules), but it's possible that it won't fit.
SPEAKER CABINET EMULATOR
The emulator's output is available only at the headphone jack and/or the balanced XLR outputs; the 1/4" outputs always bypass the emulator and come directly from the post-digital EQ. The emulator on/off switch is located on the rear of the unit. There are no parameters associated with the emulator - it's either on or off.
PROGRAM MEMORY
Contrary to some early data sheets and mail order catalogs which spec 128 factory presets and 64 User Programs, there are 100 User Programs (1-100) which can be edited or overwritten as well as 100 factory presets (101-200) which cannot be overwritten. The unit comes from the factory with the content of programs 1-100 being copies of 101-200.
FIRMWARE REVISIONS
The most recent firmware revision is 2.00.01, which is being shipped in all new GSP-2101s from the factory. Owners of older 2101s who wish to upgrade can fork over $49 to Digitech directly for a user-installable software update. (The Processor / Memory Upgrade discussed below includes the new firmware.)
Version 2.xx.xx adds a true tuner function to the 2101 to supplant the previous versions' tone reference generator. The tuner is a new option under
the Tone Ref front panel button. It also fixes some bugs and seems to speed up program changes. The MIDI Continuous Controller implementation has been enhanced, allowing a single footswitch to control a large number of effects settings simultaneously. Finally, it includes the support for the Processor / Memory Upgrade.
The 2.00.01 firmware addresses the following: - Fixed memory problem resulting from MIDI program change commands - Smoother Wah-Wah - Quick access to CC links (press/hold MIDI button) - Other misc bugs
Note: bulk sys-ex dumps are incompatible between 2.xx.xx and previous versions.
PROCESSOR / MEMORY UPGRADE (list price $249)
An area on the main circuit board is reserved for the PPC-210 Expansion Card; this option is user installable (be sure to take the necessary precautions against static damage and bent pins - if you're not comfortable with this sort of thing have your dealer do it). The PPC-210 card contains a second S-DISC DSP chip and associated DRAM memory. It "doubles both the processing power and internal memory of the GSP2101, allowing more simultaneous effects, longer delay times, bigger reverbs, etc." (quoted from a Musician's Friend catalog).
It also supports Seamless Program Changes. As explained to me by a Digitech Tech, when a program change is made, one of the processor / memory pairs continues to process the information (i.e., sound) of the first program while the second processor / memory pair works on the new program's parameters and incoming signal. Two parameters per patch are provided to support this: Hold Time and Ramp Time. These allow you to control the transition from one patch to another. Hold Time can be set to "infinite"; in this mode, a sample/hold patch can be sustained while you switch to another patch. This allows one to solo over a repeating rhythm section up to five seconds long ad infinitum/ad nauseam. Each Program has its own Hold/Ramp Time parameters.
With the PPC-210 installed, four new algorithms are available. Also, fifteen new patches (201-215) show off the dual S-DISC capabilities.
The PPC works as advertised. (Actually it works REALLY well!) Note that the seamless program change feature and the expanded algorithm feature are mutually exclusive - e.g. you cannot switch seamlessly to or from a patch whose algorithm is using both S-DISC processors.
"CONTROL ONE" FOOT CONTROLLER OPTION (list price $299)
The Control One (referred to here as the "FC") is a dedicated unit - there is only one input/output jack (no MIDI in/out is included). The jack is a 5- pin DIN connector so that a standard MIDI cable can be used to connect the FC to the 2101; both units have large caution labels over the jacks about the bad things that happen when you mistake them for MIDI jacks. The FC receives its power across this dedicated interface. A long MIDI cable is included. A treadle controller, ten Program switches, a multi-function Bank/Program/Tuner select switch, and a Bypass switch are provided. A 1/4" input is provided for an additional control pedal. (As a side note, the Control One, formerly known as the GSP-2101 FC, can be used with the Valve FX and Legend II preamps as well.)
All configuration of the FC is done via menus on the GSP-2101 itself. Here, you can do things like set the MIDI Continous Controller assignments of the internal and external footpedals, etc. You can also, for instance, set up the FC so that each footpedal turns on/off individual effects modules (Stomp Box mode).
The FC can be configured to do a number of neat things; the following items are undocumented in the manual that the writer has:
Program toggle - once a program has been selected, pressing that program's switch again will toggle the 2101 to the previous program.
Tuner function - if the 2101 has version 2 or higher firmware, the tuner can be accessed by pressing the Bank Select switch three times. At this point the tuner "eye" will appear in the FC's fluorescent display. Pressing the Bank Switch again will return you to the current program; pressing another program switch instead will select that new program.
MIDI IMPLEMENTATION
This section will summarize the contents of the "MIDI System Exclusive Documentation" manual. This manual covers sys-ex information for the S-DISC family of products, including the TSR-24, GSP-2101, TSR-12, and RP-10. It assumes a firmware revision of 2.00.00 or higher.
The beginning of the document covers Basic MIDI information such as sys-ex message format, etc. One interesting thing to note is that the Pitch Bend CC is not supported due to the "density of the information and the resources needed to process it properly".
The remainder of the document covers the 27 sys-ex commands that are available. Some examples:
Receive/Request one of the following: One Program / Algorithm / Bulk Dump / Module Table / Algorithm Link Table / Parameter Value / Error/Status Flag.
You can even send sys-ex commands that emulate front button keypresses and parameter knob turns!
The current version of the SysEx document is 1.23 which now includes data formats for program dumps. It is available from Digitech upon request, but be advised that it won't tell you much about the 2101 other than things you'd need to know if you're writing an Editor/Librarian for it.
GSP-2101 LIMITED EDITION
The Limited Edition model gets you the following:
(This is a new section. Some of the Random Comments have been moved here. I have not archived the GSP discussions so if you have any useful information that should go here, please email it to [email protected].)
- Getting the Speaker Emulator-equipped XLR outputs to 1/4" connections: Simple cables can be constructed; no low impedance to high impedance transformer is required. You'll need some shielded two conductor wire, a female XLR connector, and a 1/4" mono plug for each side (L and R). Connections:
- XLR pin 3 >> 1/4" plug tip (cable center conductor) - XLR pin 1 >> 1/4" plug sleeve (cable shield) - ankle bone connected to the... leg bone
XLR pin numbering: looking at the end of the female connector with the locking tap "up", the top left pin is #2, the top right pin is #1, and the bottom centered pin is #3.
Top Cover Removal - to remove the top panel for either PPC-210 installation or tube access, note that the top center allen keyed screw on the front panel must be removed in addition to the more obvious ones. The size of the Allen wrench required is a closely guarded Digitech secret. [Rev note: Actually, it is 7/64", which is a rather strange size. Unless you have one of those PC repair kits, you probably don't own this little guy - CLP Aug 1996]
MIDI Bulk Dump - When receiving a 2101 System Data dump (e.g., a backup you've made of your 2101's configuration), the MIDI Channel parameter located under the MIDI button must be set to either ALL or the same channel that the 2101 was set to when the Dump System Data operation was originally performed; otherwise, the data will not be recognized by the 2101.
Tuner - takes a long time to settle, and has particular trouble with the small E string (at least on the writer's EMG-equipped guitars). The display that's used on the 2101's LCD display for the tuner is not incredibly intuitive; the tuner display provided on the FC is much better. [Rev note: This has been improved in version 3.0 - CLP Aug 1996]
Wah pedal - The wah effect's response to the FC's treadle is not instantaneous, even with the "display CC" parameter turned off. (This has been improved in the v2.00.01 firmware.) [Rev note: This has been improved through the use of a new module called smooth wah - CLP Aug 1996]
Machine Lock-Up - At least one user had the 2101 lock up when he updated his firmware to version 2.00.00. In this case, the battery should be removed and the battery terminals (on the circuit board) shorted together. This should clear the unit's memory and allow you to bring the unit up (albeit with all parameters set to factory defaults).
Digitech will soon have a Wide World Web page; it will be accessed at:
http://www.harman-dod.com [Rev note:
This should be http://www.digitech.com/ -
CLP Aug 1996]
As of this writing, it's not turned on yet.
Digitech is still trying to figure out how to hook a 2101 up to a T-1
line.
In addition, there are two mailing lists that you can subscribe to, The first on is a generic list for RP-1/5/10/GSP2101/etc. users, maintained by Marcel Bernards in the Netherlands. Send mail...
to: [email protected] subject: (don't care) message body: subscribe RP-1-L
The second, more specific mailing list is [email protected], maintained by Steve Schow. Send a request for subscription to
[email protected] [Rev note: Type SUBSCRIBE in the message heading and message body - CLP Aug 1996]
Steve also has put up a cool web page at
http://www.bstage.com/gsp_html
that includes links to archives of the RP-1 and GSP mailing lists, the Digitech gear FTP site (maintained by Marcel), the S-DISC SysEx spec, and this FAQ.
Go to GSP-2101 FAQ Table of Contents