FAQ REVISION HISTORY
OVERVIEW
ARCHITECTURE
A single monaural 1/4" output jack is provided for Fx Loop Send. The signal from the output of the Analog Preamp Section is ALWAYS present at this jack regardless of the state of the Fx Loop (Bypassed, Summed, or No-Sum).
Two (left and right) 1/4" monaural jack inputs are provided as Fx Loop Returns. Each input is independantly converted from Analog to Digital, thus making the 2101 a true Stereo Digitial Signal Processor (2 independant inputs, 2 independant outputs).
Two (left and right) 1/4" monaural jack ouputs are provided as Master Outputs. The signals present at these outputs have passed through the Digital Section, the Master Mixer, and the final Output Level Amplifier. The Output Level Amplifier's knob is on the front panel in the upper right-hand corner. This is not digitally controlled, since the Master Mixer has level settings which are digitally controllable. Finally, there is NO Hardware Cabinet Emulation available at these outputs, although a software Cabinet Emulator module has been added to the 3.00.00 firmware.
A 1/4" stereo jack ouput is provided for headphones. This output signal is always present. The level is adjustable via a front panel knob (not digitally contrallable). Finally, this headphone jack includes a Hardware Cabinet Emulator designed to cut some of the high's in the same manner as typical guitar cabinets would. This Hardware Cabinet Emulator is not adjustable in any manner (furthermore, it is always active for the headphone output and cannot be bypassed), although some users have reported success in altering a couple capacitor values to change the brightness of the emulator.
Two (left and right) balanced XLR jack ouputs are provided for mixing board applications. The signals at these outputs are identical to the signals at the 1/4" master outputs. However, note that the 1/4" master outputs are BALANCED, but that typically you will connect them to a device expecitng UNBALANCED 1/4" signals. This is perfectly acceptable, but you will be negating the effect of the balanced circuit. Also, there may be perceived differences in signal strength when comparing balanced vs. unbalanced configurations as a result of the additive input in the balanced configuration. Finally, there is a switchable Hardware Cabinet Emulator available. This is the same emulator that is always used in the headphone circuit, except that it is switchable (on/off) for the XLR outputs. The switch is located in the rear of the unit next to the XLR ouputs.
ANALOG SECTION
The input levels of the 2101 have been set in such a manner as to optimize its response for as wide a variety of input levels ("hotness" of pickups) as possible.
Note that all paramters of the Analog Preamp Section are Digitally Controlled, are programmable, and can be linked to MIDI CC's and the Control One pedal/switches.
COMPRESSOR:
I have found that, when I use the headphone output for quiet late-night jamming, I like to adjust the Global EQ a little bit to better approximate the way MY cabinets actually sound. Just remember to set the Global EQ back to flat when you are done.
DIGITAL SECTION
The 2101 in its base configuration has 256 CPU blocks and 256 RAM blocks available; 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. Sometimes, it is even possible to make things fit by changing the order of effects, although this is not advised, since all Algorithms should, ideally, be created in a logical, ordered manner.
It should be noted that a user could create such complex memory-hogging programs that he/she cannot actually acheive 100 User Programs before running out of available RAM in the 2101. In this instance, he would be forced to live with whatever he can fit in his available RAM. Note that factory programs do not require any (at least not much at all) RAM since they are not stored in RAM. Instead, when a factory preset resides in the User Program area (1-100), it is actually just a pointer to the EPROM which has the data on it. Thus no RAM is consumed with a repeat of the factory data. However, if you tweak a factory program, even the slightest bit, it becomes a custom user program, and the entire data structure will occupy RAM. The amount of Program RAM is NOT upgradeable (the PPC-210 upgrade does NOT increase this type of memory).
As with User Programs memory availability, algorithms too have a limited storage space. As Custom Algorithms are created, more RAM is consumed by them. This becomes especially troublesome if they are Dual-S-Disc Algorithms since they are so complex that they effectively require twice as much memory to be stored. While each Algorithm is only stored once, regardless of how many times it is used by programs, there is not alot of Algorithm memory available. Digitech performed some tests and decided there was enough memory for about 7-12 normal-sized custom Algorithms. If you have run out of Algorithm memory with less than 7-12 custom Algorithms, then perhaps you are not normal. The amount of Algorithm RAM is NOT upgradeable (the PPC-210 upgrade does NOT increase this type of memory).
Note that while Program and Algorithm memory utilize the same physical memory chips, they occuppy disticntly separate memory address ranges within the 2101. Furthermore, these memory regions are NOT dynamic. If you eat-up all your Algorithm memory by generating alot of new Algorithms, the 2101 will NOT allow you to utilize some unused Program memory space for new Algorithms. In other words, the Alg/Program space is partitioned from one-another.
The memory inside your 2101 is backed-up with a battery, so that the information is retained in RAM. This is very much like the battery that backs up the CMOS settings in your home PC. The life of this battery is probably between 2and 5 years, although noone has ever mentioned losing their battery. None-the-less, better make sure you back up your data to your computer.
- OR -
2. Switch Seamlessly between single S-Disc programs. This allows your "Metallica Crunch" program to fade out according to your preprogrammed ramp and hold times while the 2101 is loading up your "Clean Delay" algorithm (because you punched it up on your FC-1). The small amount of time it takes the 2101 to load the second program is covered up with the sound of your previous program fading out, rather than a sharp drop in sound. Furthermore, by allowing slow fade and hold times, you can actually blend the two sounds together for a few seconds to make the transition smoother.
With the PPC-210 installed, four new algorithms are available. Also, fifteen new patches (201-215) show off the dual S-DISC capabilities.
"CONTROL ONE" FOOT CONTROLLER OPTION (list price $299 US as of Sept 1996)
The Control One (C-1) 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 (the internal pedal), ten programmable switches, a multi-function Bank/Program/Tuner select switch, a Bypass switch, and a 20 character LED display for program names are provided. A 1/4" input is provided for an additional control pedal (the external 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). See Configuring the C-1 Footcontroller for more info.
The following items are undocumented in some manual versions:
Tuner function - if the 2101 has version 2.00.00 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
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:
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. You can also access this SysEx document on the Internet.
Go to GSP-2101 FAQ Table of Contents
Written by Curtis LeMay Pastor,
[email protected] or [email protected]
Last revised as of Feb 3, 1997.