Highly Liquid Forum facebook twitter google plus rss feed
  #1  
Old 04-07-2014, 10:11 AM
oldgearguy oldgearguy is offline
Junior Member
 
Join Date: Apr 2014
Posts: 3
Default MPA rev B specs/parts question

Hello - I recently purchased an MPA kit. It seems to be missing the DIP switch. I know I can use the socket and jumper wires to (really) hardcode a MIDI channel, but was it simply missing from my package or was I supposed to supply my own?

Next - if I am installing this board in a synth that already has a regulated +5v line, I should be able to simply wire that +5v line to where the output pin of the on-board regulator would normally be soldered and leave off the rectifier diode, polarized tant, and the regulator itself, correct? I am not planning on using the +5 output from the board.

Finally - how much current does the board draw? If I am only planning on using the logic switches and not the digital potentiometers, I can skip installing those 2 ICs as well, right? Does that make much difference in the current comsumption?

Thanks for any information you can provide.
Reply With Quote
  #2  
Old 04-09-2014, 12:08 AM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Hi Oldgearguy, welcome to the forum.

Quote:
Originally Posted by oldgearguy View Post
Hello - I recently purchased an MPA kit. It seems to be missing the DIP switch. I know I can use the socket and jumper wires to (really) hardcode a MIDI channel, but was it simply missing from my package or was I supposed to supply my own?
Sorry about that. It sounds like the parts were missing. We have already been in touch over email to fix that issue.

Quote:
Next - if I am installing this board in a synth that already has a regulated +5v line, I should be able to simply wire that +5v line to where the output pin of the on-board regulator would normally be soldered and leave off the rectifier diode, polarized tant, and the regulator itself, correct? I am not planning on using the +5 output from the board.
Yes, that would work fine.

Quote:
Finally - how much current does the board draw? If I am only planning on using the logic switches and not the digital potentiometers, I can skip installing those 2 ICs as well, right? Does that make much difference in the current comsumption?
An idle board shouldn't draw much more than 20mA or so. Obviously, this can increase if you are drawing current from the logic outputs.

There is no problem with leaving the digipots uninstalled.
Reply With Quote
  #3  
Old 04-09-2014, 09:52 AM
oldgearguy oldgearguy is offline
Junior Member
 
Join Date: Apr 2014
Posts: 3
Default

Excellent information; thank you for the response. I should get some time this weekend to implement this daughterboard and incorporate it into the synth. I'll drop some pix up here once it is done.

To mimic the physical act of pushing a momentary button, the only thing I need to add is a small relay, right? I'd wire the relay across the switch contacts and then use the logic output+ground across the coil to activate it. The synth already has debounce and isolation logic to handle the switch closure, so it should be a simple mod.

Tom
Reply With Quote
  #4  
Old 04-09-2014, 09:42 PM
John's Avatar
John John is offline
Moderator
 
Join Date: Jan 2009
Posts: 3,007
Default

Quote:
Originally Posted by oldgearguy View Post
Excellent information; thank you for the response. I should get some time this weekend to implement this daughterboard and incorporate it into the synth. I'll drop some pix up here once it is done.

To mimic the physical act of pushing a momentary button, the only thing I need to add is a small relay, right? I'd wire the relay across the switch contacts and then use the logic output+ground across the coil to activate it. The synth already has debounce and isolation logic to handle the switch closure, so it should be a simple mod.

Tom
Hi Tom, yes, that sounds good to me. I recommend a small reed relay with a 5V coil voltage & integrated diode, like COTO 9007-05-01. You can also use a photorelay like TLP222AF. For reference, you might check out the MSA output schematics here:

http://forum.highlyliquid.com/showthread.php?t=1113
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 12:07 PM.


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