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Banks, Patches, and Programs:

The 2101 consists of 100 User Programs and 100 or more Factory Preset Programs. The first 100 programs (1-100) are the User Programs.

The C-1 has 10 programmable footswitches (labeled 1-10) in addition to 2 special purpose switches (Program/Bank/Tuner and Bypass). The 10 programmable switches may be programmed to perform a number of functions:

A switch may be assigned to load a particular program number

A switch may be assigned to perform a Program Up/Down action.

A switch may be assigned to perform a Bank Up/Down action.

A switch may be assigned to perform a Song List Up/Down action.

A switch may be assigned to toggle a CC (continuous control) value.

Since there are 100 User Programs and 10 switches, the 2101 was designed to accommodate 10 user banks. A bank can be considered as a preassigned set of programming instructions for the footswitches. Each bank has its own program assignments for each of the 10 switches. Thus, you can construct the first bank such that the switches 1-10 load programs 1-10, and the second bank such that switches 1-10 load programs 11-20 (this is very similar to the default 2101 configuration).

A "patch" is a term used to reference a program number used in a bank. The word "patch" is used since, in effect, a particular bank/footswitch combination is mapped or "patched" into a particular program number. Note however, that footswitches do not have to be used strictly for patches to programs. As noted above, switches may also be assigned to control other aspects of the 2101.

A Song List is a predefined ordered listing of programs, in the sequence that will be used for your "set". Song Lists can simplify your life if you play a predetermined set repetitively, thus taking some of the guesswork out of your patch switching. However, if you do not stick to regimented "sets" of predefined song ordering, you should probably consider steering away from Song Lists and learn to recall programs via the bank/patch methodology.

MIDI messages come in many forms. However the 2101 ignores almost all MIDI messages (after all, it's for guitarists, not keyboard players). However, CCs are NOT ignored. A CC is a message that is usually generated by a MIDI pedal. It would be sent by the pedal to a device,which in turn would respond to the controller change appropriately. The 2101 can respond to external MIDI CC's as well as "internal" CCs generated by footswitch events. We will not dicuss external MIDI CCs in this document.

The C-1 sends information to the 2101 about its pedal(s') postion(s) (the C-1 can accommodate a second pedal). The 2101 remapps this non-MIDI formatted data into CCs, program changes, bank changes, etc, in accordance with the bank settings stored in the 2101. If the 2101 determines that a switch is mapped into a CC, then the 2101 makes the appropriate changes to the program's parameters in accordance with the MIDI CC assignments for that program.

The C-1's pedal(s) can generate a stream of information as you rock the pedal from heel down (0%) to toe down (100%). An C-1 footswitch, however, "toggles" a CC between the MIDI value 0 (OFF) and 127 (ON). In turn, it also toggles the LEDs on your C-1 so you can determine the current state of the CC. Furthermore, you may save the program with the individual CCs in different states. When you toggle the switch, the 2101 links this event to a parameter change. The parameter will toggle between 2 distinct values defined as MIN (switch OFF) and MAX (switch ON). Note that any valid parameter value may be assigned to MIN and MAX, and that the MAX value can in fact be less than the MIN value. For example, when CC-1 is off, you want the Distortion gain to be 10.0 (this is the MIN value, because it is associated with the CC being OFF), and you would like the gain to drop to 3.6 when you activiate CC-1 (this is the MAX value because it is associated with the CC being ON). Digitech might have more appropriately named these OFF and ON rather than MIN and MAX to help avoid confusion, but it is really simple once you get used to it.

Using CCs to configure the C-1 has pros and cons as compared with the newer method of using links.

Pros:

Increased versatility, allowing more than one paramter change to be associated with a particular switch.

Allows external MIDI control as well as C-1 control.

Cons:
Slower that direct links due to the internal mapping conversion required.

Multiple parameter changes mapped to a single switch change can have a noticeable delay, causing a less-than-smooth transition.

To configure your C-1 in this manner, you will need to perform the following:
1. Program your bank settings from the MIDI->Footcontroller menu.
2. Program your CC parameter changes from within each program.
This is a rather simple task which I will illustrate in some detail.

EXAMPLE:

Let's say you have decided on the following setup:

C-1 Switch-1 === Toggle CC-1
C-1 Switch-2 === Toggle CC-2
C-1 Switch-3 === Toggle CC-3
C-1 Switch-4 === Bank Down
C-1 Switch-5 === Bank Up
C-1 Switch-6 === Program 1
C-1 Switch-7 === Program 2
C-1 Switch-8 === Program 3
C-1 Switch-9 === Program 4
C-1 Switch-0 === Program 5
C-1 Internal Foot Pedal === CC-11
This configuration allows you to have a standard configuration with 5 patches per bank, 3 controller switches, easy access to adjacent banks (without having to perform the Mexican Hat-Dance while playing Eruption), and a pedal CC value that allows for 10 reserved CC's (1-10, 1-3 of which are used in this particular bank).

To program this, go to the MIDI->Footcontroller menu:

Bank Setup Menu

Now, we are programming BANK-1, so set the Bank number to 1. Now set the Foot Switch Number to 1. Now, press 3 several times until the label "Program Number" changes to "Toggle CC". Now scroll (with the data wheel) until the value is Toggle CC Number 1. You have just programmed footswitch 1 to toggle CC number 1 when you are in bank number 1.

Program switch 2 and 3 the same way, only using CC #2 and #3 as shown in the list above.

Now, set Bank Number to 1, and Foot Switch to 4. Now press 3 several times until the label reads "Bank Up" instead of "Program Number". Now scroll once to the right with the data wheel to change the label to "Bank Down". You have now programmed switch 4 to decrement your bank number when pressed.

Program switch 5 in a similar manner.

Now, leaving Bank Number set at 1 still, set Foot Switch to 6. Press 3 several times until its label reads "Program Number" (note: it will probably already say Program Number, in which case you only need to press 3 once to make it the active field). Now scroll the Data Wheel until it reads "Program Number 1". Now switch 6 will load program 1 when it is pressed, assuming you are operating from bank 1.

Program switches 7-0 in the same manner as switch 6, substituting the appropriate program numbers as listed above.

That's it!! You are done. Well, that's not completely true. If you are playing from Bank 1 and press switch 5, you will suddenly be in Bank 2. Therefore, you need to program Bank 2 in a similar manner. For a quick shortcut when programming the bank settings, see Tips/Tricks.

As noted above, there are pros and cons to each method of programming the C-1 (see above for more info).

The methodology to configure your C-1 using links rather than CCs is documented in the GSP-2101 Users Manual

1) a standard, passive Volume pedal is the first choice (something like an ErnieBall). Just plug it in and calibrate as usual...

2) a DOD FX-17 can be used...use an adapter cable to plug the +/-5V output to the ExtPdl input on the Control one (male 1/8" TipRing plug to male 1/4" TipRing plug). You will also need a power adapter to run properly (a battery won't have the juice necessary to provide the +/-5v. Calibrate as you normally would.

3) Pedals that are considered EXPRESSION pedals (like thos that used to come with old DX7 keyboards) won't work for this application.

An "expression" type pedal has three connections (tip,ring,sleeve) for the three connections of a potentiometer. This configuration is used by keyboards, so that calibration (as the 2101/FC-1 does) is not necessary. This is because the keyboard input will put an A/D reference voltage across the (full) pot, and sample the voltage at the wiper. However, this is not possible with a two-pin connection such as you get from a volume pedal. This is why the 2101/FC-1 must be calibrated (to determine the actual max and min resistance of the two conductor connection).

So why don't Yamaha expression pedals work? It is because the pinout of the TRS plug puts the wiper of the pot at the ring instead of the tip (I just checked one with a VOM). An adapter that swaps Tip and Ring, or that puts Ring and Sleeve to the Tip and Sleeve of a Two conductor plug, will make this pedal work.

BUT, there are two other considerations when using a external pedal in the control-1. One is total resistance, and the other is pot "taper".

Resolution ----------

The total-resistance issue has to due with the resolution that the control-1 can utilize. Given that the full range of the pedal is 0-127 (to match up with then MIDI CC value range), One would want to be able to access this range in steps of one. I.e. one wants each of the 128 values to be accessable based on the pedals position. My experimental evidence shows that the pot must be at least 150K ohms in order for this to be true. Since the Yamaha expression pedal I referenced has a 47K pot, The resolution available with this pedal is aprox in steps of 3. I.e. if you're at a value of 64, and you move the pedal forward, your next possible value will be 67. The 65 and 66 intermediate values can not be measured. A Roland expression pedal uses aprox. a 9K pot. This yields even worse resolution. Volume pedals, on the other hand, tend to have high resistance pots (250K - 500K), so they will allow for full resolution. HOWEVER, they also will *not* use linear pots (as "expression" pedals do). This brings us to the next issue:

Linear vs. Non-linear taper ---------------------------

The 2101/FC-1 allows a maximum value range of 0-127 for its external pedal. Assuming we're using this whole range (i.e. full toe-down = 127 and full toe-up = 0) then the question is, what value will the GSP show when the pedal is at its halfway point? We assume that we would want a value of 64.

It turns out, that in order for a value of 64 to be registered at the halfway point of the pedal's travel, *it must use a LINEAR taper potentiometer*. In other words, the 64 value will be registered at a pedal resistance that is halfway between the calibration points. The control-1's external input *does not compensate for the audio taper of a volume pedal*. It's seems odd, then, that volume pedals are what Digitech recommends for use here.

So what happens when you use a non-linear pot (some type of "audio-taper", as in a volume pedal)? Read on:

There are as many (more!) non-linear taper curves as there are pot manufacturers. The important characteristic for us is that the halfway value of resistance *will not* be at the halfway point of the pot's travel in any non-linear pot. As an example I will show a table showing percentage of total resistance at various points in a pots travel for a "typical" linear pot, and a "audio" taper pot:
 

Mechanical % of Travel	% of Full Resistance  Linear Taper	% of Full Resistance Audio (log) Taper
0	0	0
10	5	1
20	16	2
30	27	4
40	38	6
50	50	10
60	62	20
70	73	48
80	84	78
90	95	95
100	100	100

Note that these are measured values, not ideal ranges.

Note that for the audio pot above, the 50% resistance point is about three quarters of the way through the pot's travel. Every Volume pedal will use a different curve. But since none of them will use a linear pot, the "64 point" will not be at the halfway point of the pedals travel.

To determine how your pedal is behaving, do the following: Calibrate the external pedal as usual. Then on the same page (this is for a GSP-2101) select "set min and max value". Set the min value to 0 and the max to 127. Then move your pedal through its travel until the "current" value shown on the page is 64. Make note of what your pedal's position is. If it is halfway through its travel, then you have a linear pot. If you are using a volume pedal, you are probably skewed towards the "full off" position of the pedal. (Note that this is not necessarily "bad", but understanding how your pedal is functioning can help you to use it more effectively.) Next move the pedal slightly forward and try to get the "current" reading to be at 65 and 66 and 67, etc. If you find that the reading "jumps" by twos or threes or more, then the resistance of your pedal is not sufficient to provide full resolution.

Go to GSP-2101 FAQ Table of Contents

Written by Curtis LeMay Pastor,
[email protected] or [email protected]
Last revised as of May 6, 1997.