Roland DP-8 / DP-10 / RPU-3 "half" Damper CC pedals - compatible with EV-5?

Started by CodeSmart, May 05, 2018, 10:12:23 AM

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Markwaaron@icloud.com

That would be great if you figure out how to make the RPU-3 work. It could be I was doing something wrong. Unfortunately, my limited electronics knowledge makes most of that link incomprehensible to me. Please let me know your findings. Someone who is tech-savvy like you may be able to get it to work.

admin

Quote from:  philjynx on May 31, 2018, 01:26:24 PM
Are there two Steve's? Or does Mr Conrad have THREE IDs here? Hard to keep up....


I got tired of PM messages inquiring on how to install Sustainiacs ( those questions should be forwarded to Mr. Hoover here
http://www.sustainiac.com/

So today only 2

Elantric

Admin - when I'm on my LG V20 phone ( which is 80% of the time.

Elantric

Quote from: Markwaaron@icloud.com on May 31, 2018, 01:40:43 PMThat would be great if you figure out how to make the RPU-3 work. It could be I was doing something wrong. Unfortunately, my limited electronics knowledge makes most of that link incomprehensible to me. Please let me know your findings. Someone who is tech-savvy like you may be able to get it to work.


Roland RPU-3 Inside





Roland RPU-3 Rotary Pot (ABS) 3K Linear


Roland RPU-3 Schematic  -  three circuits similar to Roland EV-5 Expression pedal, but uses  3K Linear Potentiometers
( they actually measure 3.2k with my ohm meters )

Drawn with female TRS Stereo jacks -
The real RPU-3 uses a 2 meter cable with Three TRS 1/4" Phone plugs labeled L, C, R 


compare with Roland EV-5 - uses 10K linear pot
https://www.vguitarforums.com/smf/index.php?topic=33.0

gumbo

Read slower!!!   ....I'm typing as fast as I can...

Markwaaron@icloud.com

Thank you so much for the detailed write-up on this. This forum is fantastic! Are you getting any response at all from the GP-10? I am considering taking my RPU-3 to a local music shop. They do great work on guitars and amps, and I'm guessing they could order me some 10k pots and install them. Does it look like it would be difficult or problematic for experienced guitar techs to do so? I really like the look, feel, and stability of the RPU-3, so I'd prefer to get a few of them to work rather than dealing with a bunch of separate DP-10 units.

Elantric

There are hurdles

Apparently some Roland/ Boss gear's external expression control jacks  will respond to external controllers with only a 3.2K ohm resistance - instead of the EV-5 10K resistance

Also many competing brands allow you to re-calibrate for different resistance value external expression pedals ( older Digitech GSP-2101)   

The big issue is most available potentiometers operate with a wiper that moves across a 270 degree circular rotation.

The RPU-3 uses a proprietary  potentiometer assembly ( labeled ABS) with a wiper that moves full excursion across a 90 degree rotation.

Big reveal to me is the RPU-3 custom 90 degree pots appear useful as the basis of a custom DIY drop down whammy bar controler more useful than the virtual Jeff

so have your tech locate a 10K ohm version of this



In the meantime, it may be interesting to form a list of MFX gear that could work with a 3.2K ohm pot wired like this:



and if a specific piece of gear works with a 3.2K pot, then it should be compatible with the RPU-3


There is an old trick:


Modify a pot's current resistance value to make it appear as a lower resistance pot, by soldering a new parallel resistor across Pot's contacts.


So to convert a 10K pot value in half,  solder a separate 10K resistor across Pot's contacts   = 5K pot

We can calculate the required parallel resistor value to convert a 10K pot into a 3K pot



- or use an online parallel resistance calculator  - and discover what MFX gear works with
"3.2K ohm expression pedal, but taking an  EV-5" type expression pedal with its existing 10K pot, then solder  a 4.7K resistor in parallel -  will convert it to 3.2K ohm expression pedal

- same measured 3.2K ohm resistance value as the stock RPU-3 pot




http://sound.whsites.net/pots.htm

Markwaaron@icloud.com

It would be interesting to see the inside of a DP-10. I would almost suspect it has a similarly rotating potentiometer inside, but 10k. If so, DP-10 replacement parts might do the trick.

Elantric

EUREKA





google searched on >ABS<

https://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=throttle+position+sensor
Discovered strange  RPU-3 3.2kohm  90 degree rotation pot is actually an

Automotive "Anti-Braking System component

I suspect its a ABS Throttle Position Sensor



^ inside Typical 90 degree Throttle Position Sensor potentiometer


https://en.wikipedia.org/wiki/Anti-lock_braking_system



further search shall reveal manufacturer / model type
https://www.alibaba.com/trade/search?fsb=y&IndexArea=product_en&CatId=&SearchText=throttle+position+sensor

http://bfy.tw/IWOp

similar ABS Throttle Position Sensor

These make good parts source for DIY expression pedal  / whammy bar controller

- and appear to be "beer proof"




https://www.ebay.com/itm/Accelerator-Pedal-Throttle-Position-Sensor-For-Nissan-Infiniti-18919-AM810-HY3/202211249829?hash=item2f14bacea5:g:DYkAAOSwcN1acZNC

But most are "smart" digital CAN bus (  Controller Area Network)  - uses on all vehicles these days
https://en.wikipedia.org/wiki/CAN_bus
http://www.pugaddicts.co.uk/2015/02/guide-toyota-yaris-14d4d-pedal-position.html


https://medium.com/@alexandreblin/can-bus-reverse-engineering-with-arduino-and-ios-5627f2b1709a

http://www.zlg.com/can/article/detail/id/198.html



Using MIDI over Automotive CAN ( Controller Area Network) bus
https://www.vguitarforums.com/smf/index.php?topic=23792.msg172778#msg172778


admin

Quote from: Markwaaron@icloud.com on June 08, 2018, 06:40:50 AM
Thank you so much for the detailed write-up on this. This forum is fantastic! Are you getting any response at all from the GP-10? I am considering taking my RPU-3 to a local music shop. They do great work on guitars and amps, and I'm guessing they could order me some 10k pots and install them. Does it look like it would be difficult or problematic for experienced guitar techs to do so? I really like the look, feel, and stability of the RPU-3, so I'd prefer to get a few of them to work rather than dealing with a bunch of separate DP-10 units.
http://forums.musicplayer.com/ubbthreads.php/topics/2581404/CP5_can_a_Roland_sustain_pedal
Well, it is polarity as the + and - are reversed depending on brand of pedal, sorry to argue the point.So called "half-pedals" which are really a "continuous controller" rather than a simple open/closed circuit design.

The Roland DP-10 can have the three terminals + - and earth re-configured to run in the Yamaha format.

The Roland DP-10 can have the three terminals + - and earth(sleeve) re-configured to run in the Yamaha format.

Picture is of the modified DP-10 for the Yamaha



The original Roland connection is from left to right white, black and red.
In the picture it is red,white and black (the Yamaha wiring)
Before - After
white - red
black - white
red - black

The Roland cable colour code is:
Tip is WHITE (wiper of the pot)
Ring is RED (+)
Sleeve is BLACK (Gnd)

admin

http://forum.pianoworld.com/ubbthreads.php/topics/2220211/Re:_VPC1_sustain_pedal_(F-30)_.html

http://www.joflaherty.org/VPC1/images/thumbs.html

http://forums.musicplayer.com/ubbthreads.php/topics/2155410/How_to_switch_the_polarity_of_
Fatar makes the Pro Mega triple pedal. They make it in several different configurations


The linkage is tied to a POT, 10K if I remember right. The TipRingSleve works like an adjustable voltage divider. When connected correctly a variable voltage is read and in a simplified explanation the release is varied accordingly. It gets more complicated with the drake system, Pianotec Ivory etc...


https://www.thomann.de/gb/fatar_sustain_pedals.html

https://www.thomann.de/gb/fatar_vfp315_sustainpedal_3fach.htm?sid=15c87065b489de6a8afdc6f66e75acab



admin

http://www.fatar.com/pages/VFP3.htm

VFP3-2D: Dynamic Control Pedal. Gold or Nichel finish commae. Rubber Contact open at rest on the central side and potentiometer control on the right and left side. Supplied with cable and stereo jack plug. Natural sigle box

VFP3: Switch Control Pedal. Gold or Nichel finish, Rubber Contact open at rest. Supplied with cable and stereo jack plug. Natural single box.

VFP3-D: Dynamic Control Pedal. Gold or Nichel finish, Rubber Contact open at rest on the central and left side and potentiometer control on the right side. Supplied with cable and stereo jack plug. Natural sigle box.

VFP3-2D: Dynamic Control Pedal. Gold or Nichel finish, Rubber Contact open at rest on the central side and potentiometer control on the right and left side. Supplied with cable and stereo jack plug. Natural sigle box.

^^ VERY TOUGH TO FIND THIS FATAR MODEL# VFP3-2D

--
Yamaha FC3A - Piano Style Continuous Sustain Pedal
https://www.bhphotovideo.com/c/product/1130920-REG/yamaha_fc3a_piano_style.html
http://www.brainspawn.com/forum/viewtopic.php?t=4272
http://forums.musicplayer.com/ubbthreads.php/topics/2881904/3

https://docs.google.com/spreadsheets/d/1ueDY9We68ywmSWTJRo8d61rNnBKRtSLAJDnOUllbd1s/edit#gid=0

Markwaaron@icloud.com

#37
Takeaway point for me. Dp-10 units should work for my application (bend string pedal steel style on six separate gp-10 boxes controlled by the same hex pickup). It sounds like the foreign supplier makes a triple damper unit that may use 10k pots as are needed to continuous control a gp-10 through the exp 2 in. A midi solutions $130 box might allow you to do any kind of potentiometer, but that becomes cost prohibitive when you want 1 per string. Dp-10 units ordered. I will keep you informed of how well they work for this application.
A friend says you can do a similar trick to increase resistance by running in series rather than parallel, but I think it makes the most sense to just use the DP-10 units that already have 10k pots if the application is on a GP-10 or other Roland box that is compatible with an EV-5

gumbo

Read slower!!!   ....I'm typing as fast as I can...

CrisOliveira

Hello.
I signed up for this forum just to ask if anyone has a copy of or a link for the Roland RPU-3 schematic, which is now offline in this thread's post.


Elantric




Its essentially three of these, with three TRS cables
Roland RPU-3 Schematic  -  three circuits similar to Roland EV-5 Expression pedal, but uses  3K Linear throttle position sensor Potentiometers
( they actually measure 3.2k with my ohm meters )


The real RPU-3 uses a 2 meter cable with Three TRS 1/4" Phone plugs labeled L, C, R


gumbo

I love the way we are still messing with this stuff!!
...soooo easy to hack!

Thanks Steve...I started looking for this in my pile of bits but you beat me to the punch.  ;D
Read slower!!!   ....I'm typing as fast as I can...

CrisOliveira

Thank you!
EDIT: Do you happen to know if the RPU-3 and the KDP-70 are the same thing, only with different connection?

Elantric



gumbo

Can't find anything (written) yet about the KDP-70 that gives an indication of the pedal actuation, but it's worth noting, at least from my previous digging into keyboard pedal units that 'some' multi-pedal units do NOT have potentiometers on every individual pedal.

Frequently the centre pedal was simply an On-Off circuit....sometimes one can glean more information by finding out what actual keyboards are suitable for these multi-pedal assemblies, and researching what those KEYBOARDS expect as individual remote switching circuits...that's how I ended up approaching this, many years back...

Digging into the remote pedal circuitry of the Roland FP-30 digital piano might get you some answers..

HTH

Cheers,
Peter
Read slower!!!   ....I'm typing as fast as I can...

Hammerhands

I've used the DP-10 as an expression pedal.  I've got two of them, I rewired one of them so the polarity is reversed.  I also created an adaptor that reverses the polarity, so I can have either or both using either polarity.

I took some pictures of the inside of the DP-10, probably before I rewired it?  Now how do I post them...

The little board with the pot is labelled DP-8.

I created the adaptor using Neutrik modules, it is rather big and heavy.