Author Topic: Behringer FX 600 reverb mod?  (Read 215 times)

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ponce

Behringer FX 600 reverb mod?
« on: November 30, 2017, 05:46:16 PM »
Is there a way to reprogram the Coolaudio V1000 in this pedal to get the reverb instead one of the existing effects?

ponce

Re: Behringer FX 600 reverb mod?
« Reply #1 on: November 30, 2017, 06:33:58 PM »

Mark Hammer

Re: Behringer FX 600 reverb mod?
« Reply #2 on: December 02, 2017, 01:12:07 PM »
According to the datasheet, or at least my understanding of it, all the reverb effects have the most significant bit - set by a positive or ground connection on pin 8 of the chip - set to ground.  This could be confirmed by reading the DC voltage from pin 8.  If I'm right, then it remains at +5V, no matter what the FX switch is set to.  IN other words, that rotary switch seems to select across the 3 least significant bits, and leaves the most significant bit alone.

Assuming you have the chops and tools to do the appropriate surgery, and the relevant traces are visible and accessible, the answer to your question would seem to be installing a SPDT mini-toggle to select pin 8's voltage between +5V and ground, selecting between the upper and lower 8 effects, respectively.

Could be tricky.

ponce

Re: Behringer FX 600 reverb mod?
« Reply #3 on: December 02, 2017, 04:21:04 PM »
I have some experience in building analog pedals, last being a Boss CE-2 clone, but I have no knowledge in computing and binary code applications.
 I understand that lifting some of the chip's pins sets it in the internal mode but then it's isolated from the rest of the circuit/controls, giving only wet signal. I'd like to be able to get at least one of the reverbs stored in the chip and when possible, retain the controls function.
I'm not sure I understand how to connect the switch - lift the lug 8 and short it to ground via SPDT? It would be great if this mod worked.
« Last Edit: December 02, 2017, 04:59:59 PM by ponce »

Mark Hammer

Re: Behringer FX 600 reverb mod?
« Reply #4 on: December 02, 2017, 05:34:26 PM »
Without getting into too much detail, the chip has 16 built-in programs.  Sixteen = 2x2x2x2, or 4 bits that can be 0 (gnd) or 1 (+5v).  The "least significant bit" (LSB) is the one on the far right, asnd the "most significant bit" (MSB( is the one on the far left.  So a digital code of 0001 sets the LSB to 1 (+5V), and the other three to 0.  The switch in the pedal changes the three lower bits, but doesn't touch the MSB.  To take advantage of the reverb effects, and retain the built-in ones, one would have to use an additional switch to select or deselect the MSB.

Make sense?

Judging from the chip's default built-in programs, compared to what the pedal offers, it appears the pedal uses external programs for at least some of what it offers.  So, the flanger, chorus and phaser effects may be what comes built in to the chip, while the pitch-shift and tremolo are clearly part of an external program.  It may be that Behringer simply ported those first three effects to whatever external memory chip the pedal uses, or else the rotary switch selects both pin 2 for internal/external programs, in addition to pins 5/6/7 for the specific programs to be used.  I have no idea, but the switch would need to be more complex if it opted for some internal and some external.

To mod the pedal and make use of the 8 reverb programs built into the chip, you'd need to be able to both deselect the external memory chip AND set the MSB to 0.  That would require a DPDT toggle.  Those can be gotten fairly small, so as to fit the available space.  Identifying HOW to do the mod, in a physical sense, is another matter.

ponce

Re: Behringer FX 600 reverb mod?
« Reply #5 on: December 02, 2017, 06:35:47 PM »
From this site:

http://www.noystoise.com

DD600 uses a CoolAudio V1000 chip which is basically an Alesis knock-off. The V1000 is being controlled by a little micro-controller with custom Behringer programs to generate the lackluster reverbs and delays. However, the V1000 has 16 of its own effects programs that can be accessed pretty easily by simply disconnecting the appropriate pins on the board, and adding a 4 bit switch to select all of the programs. Of course this renders the controls of the pedal useless,  so you have to build your own wet/dry mix control. The other thing i like to do with this chip is replace the V1000's timing crystal with a VCO. Sweeping the frequency of the VCO changes the sample rate of the V1000 and causes a really great swooshing pitch bend. The effect sounds a little bit different in each of the 16 programs.


ponce

Re: Behringer FX 600 reverb mod?
« Reply #6 on: December 02, 2017, 06:41:23 PM »
Maybe I don't need the controls for start.I have a 4 bit dip switch in my stash, maybe I should try a brainless circuit bending method, but is there a risk of frying the chip?

ponce

Re: Behringer FX 600 reverb mod?
« Reply #7 on: December 02, 2017, 07:34:35 PM »
Would lifting the pin 2 and installing  the switch to temporarily enter the internal mode and placing the 4 bit dip between the 4 program lugs and the board contacts do the trick? Then just dialing on the dip sw. according to the list to get the corresponding effects?