To get right to the point, yes. All you need to do is cut that one trace and it will open up access to the FV-1's other programs.
You need to use pins 16, 17, and 18 as binary input to determine which program you are using. As it is, the li'l reverb has pin 16 low, and pins 17 and 18 high (via the 22k pull up resistors to +3.3v). Pin 16 is connected to +3.3v via a 22k resistor as well, but ultimately, it is shorted to ground (by the trace you will need to cut). If you understand this, then you should understand that the binary code that is being sent to the FV-1 is "011", which in decimal means program number #3, right? Because 011 is binary for decimal 3, which would be "pitch shift" according to the data sheet. But this assumption would be incorrect, obviously since we are using one of the reverb programs.
In programming, you are often times given the option of reading binary in "least significant bit first" or "most significant bit first". Normally, when you read anything, you go from left to right, whether it's binary or decimal. So the number 173 in decimal is made up of 100 + 70 + 3. This is MSBF. If you were to write dec 173 in LSBF, you'd simply write it backwards as 371. The FV-1 uses LSBF, so this means that 011 is actually program #6, "reverb 1". This is because in binary LSBF, you read the 1's column first, then the 2's column, then the 4's column, i.e., you just read it backwards.
This is why the data sheet refers to PIN 16 as "program select LSB", and PIN 18 as "program select MSB". But the data sheet doesn't explain that the input is read as LSBF. It's important that you understand this first, so you know which programs you are selecting.
Cutting that one trace disconnects pin 16 from ground. This gives you a binary code of "111" or program #7 (reverb 2). You have many options for 3-bit decoding. The simplest option in this case would be to use three separate SPST toggle switches. Connect the pole of one switch to one program select pin. Connect the throws of all the switches to ground. When a switch is "off", it leaves that program pin high and gives you a "1". When the switch is on, it shorts that pin to ground and gives you a zero.
If you do this, you will probably want to add POT1 and POT2 as well, because you won't have control over some important parameters in other programs. If you compare the Li'l Reverb schematic with the datasheet, you'll see that POT1 and POT2 are actually already there, they are simply hardwired to be at "noon". So to use actual potentiometers, you'd remove the 22k resistor pairs. You'd connect Lug 3 of your pots to 3.3v and lug 1 to ground. Connect the center lug or wiper to its respective pin.
IMO, there is absolutely no difference between reverbs 1 and 2. And program #5, doesn't do anything at all. It simply passes unaffected signal, which as the "test" program, is all it's supposed to do. This information may be of some significance if you are deciding to use a rotary switch of some sort, as you would only need 6 positions. This may make it easier for you to find/design a suitable switch/interface
_________________ *patience is a virtue* Please do not PM me. email is prefered. keith@buildyourownclone.com
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