Behringer US600 - Harmonizer modification

[mercury1]

Earlier this year I picked up a behringer us600 intelligent harmonizer. I was surprised how well it worked in my configuration (harmonizer on separate input of amp 100% wet). The only problem is changing keys on the fly. There is a potentiometer (15k I believe) that selects the key, I think this works as a voltage divider but schematics are unavailable . My idea is to remove the pot and replace it with a stereo 1/8th jack and make an extention pedal out of a volume pedal with a 12 position dual pole rotary switch wired as a pot using a resistor ladder, one set of poles for the circuit and another for a battery and set of led's to let me know what key I'm in. This is a very low-tech approach but I think it will work. What I would rather have is an up and down momentary switch to select the key using a digipot or something but the step size is too small
I need 12 steps and most are 60+. Also how could the led key indicators work (comparator?)
.I have only got $50 in the pedal so no major loss if i kill it trying to make something worthwhile. If anyone has any ideas or knowledge of this kind of circuit your input would be greatly appreciated

[gumtown]

In the golden olden days of analog, you used to get all sorts of electromechanical doodads, up/down push buttons that turned a pot CW/CCW with waxed string.

There was also thumb wheel BCD and Decade dials with up/down pushbuttons, where you added your own resistors for the 10 or 16 positions.

Maybe a modified Expression pedal (or sewing machine treddle) with the pot replaced with a 12 position indent rotary switch and the indication leds as you described.

[Elantric]

Here's the manual
http://www.behringer.com/assets/US600_P0532_M_EN.pdf

The existing External Expression pedal input can be used to change the pitch

Some perspective on Mods are  here
http://www.freestompboxes.org/viewtopic.php?f=1&t=16647

t turns out that the US600 is in the "RSM" range of Behringer pedals. This stands for "Real Soud Modelling", and means they are copies of Line6 pedals, not Boss. Therefore they use a Freescale DSP (a 56364), not the V1000, not a BlackFin either (those are in EHX products).

I have a BSY600 open on the bench right now, and i plan to trace (some of) it. There is still an Atmega for "user interface", but i don't know yet where the DSP code is stored. If it's inside the Atmega and its lock bits are set, it might be tricky to dump it.

Detailed gutshots of any RSM pedal are welcome !
If you're ready to loose the original program, it might be a low-cost alternative to the ToneCore DSP.

http://freestompboxes.org/viewtopic.php?f=11&t=8175&p=145390&hilit=us600#p145390



Heres a circuit bending hack site from Russia

http://vtol.cc/filter/fx
circuit bending the Behringer US600
http://vtol.cc/filter/fx/Behringer-US-600

https://vimeo.com/26545242#at=3



The similar DR600 schematic is attached

The only problem is changing keys on the fly. There is a potentiometer (15k I believe) that selects the key, I think this works as a voltage divider but schematics are unavailable . My idea is to remove the pot and replace it with a stereo 1/8th jack and make an extention pedal out of a volume pedal with a 12 position dual pole rotary switch wired as a pot using a resistor ladder, one set of poles for the circuit and another for a battery and set of led's to let me know what key I'm in. This is a very low-tech approach but I think it will work. What I would rather have is an up and down momentary switch to select the key using a digipot or something but the step size is too small

50K linear Pot in an external expression pedal should do it 

[mercury1]

Thanks for the info, I guess I should go with the low-tech option. The expression pedal does vary the pitch even in harmonizer mode but that's useless for changing the key as it changes the dry to wet pitch relationship not the scale. Too bad they didn't make it that way from the factory. I find it curious they labeled the input "exp/ctl" as if it was intended then later rejected for whatever reason. I watched a cool youtube clip on digipot circuits by Jeri Ellsworth but no mention of changing the step size . Thanks for the help and ideas, I'll post some pics if I have any success.

[mercury1]

I finally got around to preparing the pedal for the potentiometer bypass. I chose a stereo narmalled (switching) 1/8" mini jack. The pot removed, I then wired jumpers from the board to jack and back to the pot. The jack lifts the tip and ring when active, bypassing the internal pot by lifting both ends of the pot (wiper is used as com). With the leads straightened and insulated so as not to touch the board, I then re soldered the pot case back to the board. With a 50k pot exp pedal I should be able to vary the key remotely. Of course I will mod the exp with a 12 position rotary switch with a resistor. Ladder to replicate the action of the pot. Here are some pics

[mercury1]

 I did a test run with 50k pot in expression pedal as suggested ,it works changing keys through my 1/8 potentiometer bypass but it is very hard to find the desired key without indicators (leds) . Good enough to say it functions without hum or other anomalies . I will order the double pole 12 position switch for the final build. Here is pic and video

[The Rover]

Have you managed to finish the project?

What do you think, is it possible to replace the internal pot with a 12 step switch?

[mercury1]

I haven't finished the project but if you made it this far. The pot would be replaced with a dual 12 step rotary switch with one 1 stage having a resistor ladder ( 11 divided into total resistance = 4500-4600 ohms per step) and the other stage having a battery and leds for each step . Also leds must have a resistor in series corresponding to their color to eliminate burn out. The switch must be true Dual 12 step so the circuit voltages of the stages don't short together. The pedal works well as it is for changing the key before the song starts but impossible to find the key during the song without led indicators. The reason I didn't finish is; song material requiring these abilities got dropped so I never got back to it. Its a worthwhile project though as a stompbox harmonizer with on the fly key change ability has yet to be produced. That's kind of silly seeing most material with harmonies shift between Ionian major and mixolydian or aeolian minor and dorian or modulate requiring key change.

[admin]

another Behringer pedal mod
https://www.thegearpage.net/board/index.php?threads/behringer-uv300-vibrato-modded-and-rehoused.547140/


While perusing some forums I ran across several recommendations for the Behringer UV300 vibrato, especially when a new one can be had for about $30. Well worthwhile if you want to get a vibrato but not spend a lot of money. I also ran across a post to modify the rate to slow it down, sounded interesting so I bought one. The stock UV300 does sound quite good, very nice vibrato. I can see the desire to have a slower rate though. Using it on bass, I like to have the rate sloowwww with high depth. It adds a bit of dimension, the same for chorus for me. A few other things with the stock UV300 is that it is not true bypass, if that matters to some, and the housing is rather unattractive and plastic. Although it would probably hold up, as I have had an old Arion plastic pedal that shows no wear. Nevertheless, I decided to do a few modifications and rehousing. Thanks to Uma Floresta for the info on which capacitors control the rate. Sure saved me time tracing through the schematic and investigating the layout.
The mods:
I added a foot switch to place in parallel with the rate modulation capacitor C15 so they would slow the rate down considerably in one position and stock rate in the other. I removed the pc mount pots in place of chassis mount pots. Values are Rise 250k (a) audio, Rate 250k (c) reverse log, Depth 50k (B) linear. You could use the existing pots, however with the rehouse and using a larger box it seemed best to space the controls out a bit. The stock jacks could be used also; I opted to replace with new chassis mount. I added a true bypass switch. The stock pedal has a mode switch to switch between latch (typical step on pedal once effect is on, step on pedal effect is off), bypass (no vibrato), unlatched (effect is only active when you press the pedal). I put the mode in unlatch, added the true bypass, and shorted across the stock effect pedal footswitch. If anyone looks to mod a UV300 a few things to consider: The rise really doesn’t seem to have much effect, you could set and forget and only have the rate and depth as accessible controls. The input jack needs to be a stereo switch type jack with the tip switched. If the tip is not switched, when the unit is powered and you plug in, there will be oscillation that can only be rid of by power cycling. These are simple mods and rehouse to make the pedal attractive and more usable. In the pics you see several wires jumpered to C15 and C12. In the end I only placed a cap in parallel with c15, the black/red wires. I decided upon having footswitch place in parallel with c15 a 0.37 mf cap. This yields a very slow rate at the ccw position, to a moderate speed at cw position. The speed readily switches between the fast/slow speeds with the footswitch. I cut the pcb a bit to fit the new box. And that’s the finished modded, rehoused UV300+*. The graphics were created on the computer, printed onto decal paper, applied and shot with several coats of gloss lacquer.
Here a few pics of the build: the modded caps, shortened pcb, completed, completed in use.
Enjoy…… Lapicide