Highly Liquid Forum facebook twitter google plus rss feed

Go Back   Highly Liquid Forum > Discontinued Products > MPA

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 09-18-2010, 06:23 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default MPA Replacing Wah potentiometer

Hello,
I've just ordered MPA-100K to replace the potentiometer in my guitar wah so I can control the wah with one of the expression pedals on my Behringer FCB1010.

I've also purchased a 9V small signal relay to replace the stomp switch in the wah for remote bypass following the post on how to drive a small signal relay from the logic outputs.

My question is this:
Can I configure the MPA to control a potentiometer and logic output with the same CC#, AND have the logic output respond to a value of 127 for off and 126-0 for on?

I essentially want the wah on as soon as I move the expression pedal downward, and off when I return it to full up position.

I figure this is much more convienent then having to to trigger the bypass out, move my foot to the wah, then move my foot again to trigger the bypass in.

Thanks in advance,
Dom
Reply With Quote
  #2  
Old 09-18-2010, 10:51 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Hi Dom,

Quote:
Originally Posted by domct203 View Post
Can I configure the MPA to control a potentiometer and logic output with the same CC#, AND have the logic output respond to a value of 127 for off and 126-0 for on?

I essentially want the wah on as soon as I move the expression pedal downward, and off when I return it to full up position.
I understand what you're saying. Yes, you can configure an MPA pot and logic output to respond to the same CC--but unfortunately, the logic CC mode is 0-63 = "off" and 64-127 = "on".

Now--since you're using a relay, it's easy to invert this to "0-63 = on, 64-127 = off". But not the exact values you want.

Is it possible to configure the expression pedal to send an additional message along with the CC value?
Reply With Quote
  #3  
Old 09-19-2010, 02:00 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

John,
Thanks for the quick response.

Unfortunately, the expression pedal is unable to send any other message.

Dom
Reply With Quote
  #4  
Old 09-25-2010, 03:33 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Sent a private message about this.
Reply With Quote
  #5  
Old 09-25-2010, 10:56 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Talking

Reply Sent!
Reply With Quote
  #6  
Old 09-29-2010, 04:14 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Here's your config request:

Quote:
All Potentiometers and Logic Outputs MIDI Channel set by DIP Switch.

Potentiometer 0, CC#20
Potentiometer 1, CC#21
Potentiometer 2, CC#22
Potentiometer 3, CC#23

Logic Output 0, CC#20
Logic Output 1, CC#21
Logic Output 2, CC#22
Logic Output 3, CC#23
Logic Output 4, CC#24
Logic Output 5, CC#25
Logic Output 6, CC#26
Logic Output 7, CC#27

Potentiometer 0-3 Power-Up Position=127
Logic Output 0-7 Power-Up State "Off" (0V)
And the SysEx to achieve it:

Code:
F0 00 01 5D 01

00 02 14
00 02 15
00 02 16
00 02 17

00

10 14
10 15
10 16
10 17
10 18
10 19
10 1A
10 1B

7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7
I'm also attaching the code as a binary .syx file.
Attached Files
File Type: syx mpa-dom.syx (47 Bytes, 356 views)
Reply With Quote
  #7  
Old 09-29-2010, 04:55 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

Thanks again John, I really appreciate all the help with this project.

Your customer service is AAA+++.

Dom
Reply With Quote
  #8  
Old 10-20-2010, 02:51 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Dom, glad to help out. I hope you'll post some project photos or a demo video of the MIDI wah.
Reply With Quote
  #9  
Old 10-21-2010, 11:15 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

Hi John,
I've been real busy these past couple of weeks so I'm a little behind schedule. Here's what I have done so far:

Here are all the PCB's.

MPA 100K completed:


BYOC Wah Board:


DIY Relay Board (Inspired by RG Keen):


DIY LED Board:
Reply With Quote
  #10  
Old 10-21-2010, 11:16 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

Here are some shots of me preping and etching the Relay and LED Boards. I made two of everything just in case:



I used plastic wire ties as handles. It also works as a great way to keep the boards off the bottom of the etching container.

Reply With Quote
  #11  
Old 10-21-2010, 11:18 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

I placed the main etching container inside a second container to form a "double boiler" type setup. I put very hot water in the bottom container to heat the etchant and speed up etching time. I completely etched the Relay Board in about 7-8 min this way.


Here's the freshly etched boards:


And the Relay Board as I start to populate it:
Reply With Quote
  #12  
Old 10-21-2010, 11:22 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

Here are some shots of the finished rack mount chassis. The paint is Krylon Metal-Coat Red. As you can see, I really love Waterslide Decals LOL.

Here's the front:



Reply With Quote
  #13  
Old 10-21-2010, 11:23 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

And the rear of the chassis:


Reply With Quote
  #14  
Old 10-21-2010, 11:30 PM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

I'm super happy with how everything is coming out so far. If it sounds half as good as it looks I'll be stoked!

Here's the Circuit I used for the Relay Board, and the parts needed:


I improvised a design I found at Geofex.com by RG Keen.

I did the PCB design in Pad2Pad. What a great FREE piece of software.

Oh, and yes I noticed I have the square solder pads as the + and the round as -, whoops! Oh well LOL

I'll post more when the project is complete, and if possible a video or some sound samples.

Dom

Last edited by domct203; 10-21-2010 at 11:34 PM. Reason: Spelling
Reply With Quote
  #15  
Old 10-22-2010, 02:59 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Looks awesome. Once it's complete, this will be a blog post for sure...

Thank you for posting the photos.
Reply With Quote
  #16  
Old 10-29-2010, 02:38 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

I just finished assembling the unit and thought I would share some more pics.

Everything works electricly, but it's too late to check how it sounds.

Thanks for all your help John, the SysEx works flawlessly.







I used Radio Shack 10mm insulated standoffs for all the PCB's:


Last edited by domct203; 10-29-2010 at 02:43 AM.
Reply With Quote
  #17  
Old 10-29-2010, 02:42 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default







Reply With Quote
  #18  
Old 10-29-2010, 02:45 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default

Here's some closeups:



Reply With Quote
  #19  
Old 10-29-2010, 02:47 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default







Reply With Quote
  #20  
Old 10-29-2010, 02:48 AM
domct203 domct203 is offline
Junior Member
 
Join Date: Sep 2010
Posts: 20
Default





Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 10:24 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.