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  #1  
Old 10-22-2012, 09:05 AM
mr.chifly mr.chifly is offline
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Default Midi controlled wah + expression pedal

Hello:
I'm doing a project similar to this post

http://forum.highlyliquid.com/showthread.php?t=384

The target is to activate a wah wah when loading a program on my Midi foot controller (FCB 1010) and disabled when loading another without the CC number ( with the same type of ' relay bypass circuit'). I also want to use other pot as an expression pedal when loading another different program. This must to be 50Kohm aprox. ( between 25 Kohm and 50 Kohm according to the manual). Would it be right a configuration as below to activate and control the wah wah? ( Pot 1 controls the wah and logic output 1 activates the relay). Would it be enough put a 50kokm resistor in parallel to the pot 2, to control the expression pedal?


F0 00 01 5D 01

00 02 40
00 02 41
00 02 42
00 02 43

00

10 40
10 41
10 42
10 43
10 44
10 45
10 46
10 47

7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7

Name:  rmtsw3.gif
Views: 1189
Size:  4.6 KB


Thank you in advance

P.D.: I apologize for my English. I don't know if it's written correctly. I hope you understand the query.
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  #2  
Old 10-25-2012, 08:14 PM
John's Avatar
John John is offline
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Hi Mr. Chifly, welcome and thank you for your patience.

Quote:
Originally Posted by mr.chifly View Post
Hello:
I'm doing a project similar to this post

http://forum.highlyliquid.com/showthread.php?t=384

The target is to activate a wah wah when loading a program on my Midi foot controller (FCB 1010) and disabled when loading another without the CC number ( with the same type of ' relay bypass circuit'). I also want to use other pot as an expression pedal when loading another different program. This must to be 50Kohm aprox. ( between 25 Kohm and 50 Kohm according to the manual). Would it be right a configuration as below to activate and control the wah wah? ( Pot 1 controls the wah and logic output 1 activates the relay).
Ok. I will comment on the code below.

Quote:
Would it be enough put a 50kokm resistor in parallel to the pot 2, to control the expression pedal?
It's not possible to give a complete answer to this question without seeing the application schematic. Regardless, my best answer would be to experiment. You'll get the best result by simply listening to the output of the circuit with different resistances in place.

If you want a resistance between 25k and 50k, and you need to use a variable resistor that goes from 0 to 100k (such as an MPA output), you can use a 33k resistor in parallel with the variable 100k. Now your variable resistor goes from 0-25k. Then, add a 25k resistor in series to move the range to 25k-50k.

You can use a parallel resistance calculator like this one to help:

http://www.1728.org/resistrs.htm

Note that adding parallel resistances will alter the "curve" or "taper" of the variable resistor.

It should also be noted that MPA potentiometer outputs have a loose tolerance of 30%, so finding the exact values for your circuit will probably require some trial-and-error.

Quote:
F0 00 01 5D 01

00 02 40
00 02 41
00 02 42
00 02 43
This looks good to me. The MPA potentiometer outputs 0-3 will respond to CC #s 64-67 (40h-43h).

Quote:
00
10 40
10 41
10 42
10 43
10 44
10 45
10 46
10 47
For the above, logic output 0 will be "on" if a CC #64 with value > 63 is received. It will go "off" when CC #64 with value < 64 is received. Is that what you want?

If you want the logic outputs to respond to program change messages instead, you can use modes 03h to 09h.

Quote:
7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7
The rest is fine.

Quote:
Thank you in advance

P.D.: I apologize for my English. I don't know if it's written correctly. I hope you understand the query.
Your English seems excellent to me.

Please let me know if I have answered your questions. I'd be glad to continue the conversation.
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  #3  
Old 10-25-2012, 09:54 PM
mr.chifly mr.chifly is offline
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Hello again:
First, thanks for your answer.
Now I understand that the logic output not only obeys the CC number; also to its value. As I said, the foot controller that I will use is a FCB 1010. It is assumed that multiple controllers can transmit at a time (' # 2 expression pedals with freely assignable MIDI channel, controller number and range
# Simultaneous transmission of five MIDI program change commands and two MIDI controllers per preset' it's read in behringer's website). I think I will set it to in the same preset, send one controller for the potentiometer and one for output logic. Something like this:

F0 00 01 5D 01

00 02 00
00 02 01
00 02 02
00 02 03

00

10 04
10 05
10 06
10 07
10 08
10 09
10 10
10 11

7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7

The preset in that the wah runs CC's# 00 and 04 ( this one with value 64) are sent. This would work, isn't it?.

Thank you again.
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  #4  
Old 10-26-2012, 12:49 PM
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John John is offline
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Yes, I think your approach will work.

One other thing: make sure to send CC #4 / Value 0 with the other presets where you want the wah to be "off".

Let us know about your results!
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  #5  
Old 01-10-2013, 10:19 AM
mr.chifly mr.chifly is offline
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Quote:
Originally Posted by John View Post
Yes, I think your approach will work.

One other thing: make sure to send CC #4 / Value 0 with the other presets where you want the wah to be "off".

Let us know about your results!
Hi again:

I'm trying to program the MPA with one MiDI interface ( photo below) and I can't get. It Keeps with the factory configuration ( I've checked with the foot controller and works with that configuration). I've tryed with mac an PC, with sysex librarian and Bome's sendsx software. The steps that I follow are:
- Power on Mpa unit
- Connect Midi out interface to Midi In MPA
- Run program
- Send syx file

The led of Interface blinks but anything happens in MPA. What am I doing wrong?.

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Last edited by mr.chifly; 01-10-2013 at 10:22 AM.
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  #6  
Old 01-10-2013, 12:27 PM
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Let's make sure that the MIDI interface is successfully sending the sysex.

You can perform a loopback test. Connect the MIDI Out of the USB MIDI interface directly to the MIDI In of the MIDI interface. If you select both in SendSX, can you see the exact MIDI message in the "Midi In" pane that you send out from the "Midi Out" pane?

You might want to read this thread regarding the MIDI interface that you have:

http://forum.highlyliquid.com/showthread.php?t=738

Some of them are very buggy and will not send SysEx properly.
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  #7  
Old 01-10-2013, 04:10 PM
mr.chifly mr.chifly is offline
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Quote:
Originally Posted by John View Post
Let's make sure that the MIDI interface is successfully sending the sysex.

You can perform a loopback test. Connect the MIDI Out of the USB MIDI interface directly to the MIDI In of the MIDI interface. If you select both in SendSX, can you see the exact MIDI message in the "Midi In" pane that you send out from the "Midi Out" pane?

You might want to read this thread regarding the MIDI interface that you have:

http://forum.highlyliquid.com/showthread.php?t=738

Some of them are very buggy and will not send SysEx properly.
I've performed the loopback test right now. When I send this file:

F0 00 01 5D 01

00 02 00
00 02 01
00 02 02
00 02 03

00

10 04
10 05
10 06
10 07
10 08
10 09
10 10
10 11

7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7

I've received this:

90 00 01
F0 00 00 02 00 00 02 00 00 02 00 00 02 00 00 00 00 00 00 00 00 00 01 00 00 F7

???

Then, I suppose that the Midi interface don't works fine... Isn't it?

Thank you again
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  #8  
Old 01-15-2013, 01:49 AM
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John John is offline
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Quote:
Originally Posted by mr.chifly View Post
I've performed the loopback test right now. When I send this file:

F0 00 01 5D 01

00 02 00
00 02 01
00 02 02
00 02 03

00

10 04
10 05
10 06
10 07
10 08
10 09
10 10
10 11

7F 7F 7F 7F

00 00 00 00 00 00 00 00

F7

I've received this:

90 00 01
F0 00 00 02 00 00 02 00 00 02 00 00 02 00 00 00 00 00 00 00 00 00 01 00 00 F7

???

Then, I suppose that the Midi interface don't works fine... Isn't it?

Thank you again
The received sysex message should be identical to the one that was sent. (There is just a cable connecting the output back to the input! ) The format of the sysex message that you are sending looks ok, but clearly something is wrong with either the sending or receiving of it. Do you have a different USB MIDI interface you can try?
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  #9  
Old 01-16-2013, 08:56 AM
mr.chifly mr.chifly is offline
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Quote:
Originally Posted by John View Post
The received sysex message should be identical to the one that was sent. (There is just a cable connecting the output back to the input! ) The format of the sysex message that you are sending looks ok, but clearly something is wrong with either the sending or receiving of it. Do you have a different USB MIDI interface you can try?
I finally managed to make it works!! I've used my MIDI keyboard as an interface!. Works fine with that configuration and behringer foot controller. Now the rest of assembly ( wah, expression, relay circuit...)

Thanks
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