MPS wiring diagram for the Bridechamber Panel Layout

moonagedaydream · Joined: Sep 28, 2011 Posts: 17 Location: Waco, TX

Ok, so I got my panel in the mail today. I'm a little confused about which cv inputs to leave out to keep from killing my mps. Question

are you guys talking about additional mods? or are these things that are marked on the panel that shouldnt be there...

jumunius · Posted: Mon Oct 31, 2011 1:28 pm Post subject:

The Noise CV is not supposed to be used, and in fact was left off the board.

But some people have added it without problems. I just added it to my build and didn't break anything yet. (Well, I did fry one chip but I think it fried due to a short.)

To add Noise CV, I just added a diode in series with the Noise CV signal to remove any negative voltages. This seems to work well for adding external percussive envelopes or square wave lfos, but works poorly for other LFO shapes since you lose the bottom half of the waveform.

I was also thinking that the better way to do this would involve putting the diode between the sum of CVs (frequency knob + sweep knob + noise CV input) and the pin of the 13700 that the cvs feed into. But I'm kind of a dilettante; people like Uncle Krunkus probably have a much clearer understanding of what would work best there. (I mean, if Thomas Henry took it out of his design there must have been good reason!)

moonagedaydream · Joined: Sep 28, 2011 Posts: 17 Location: Waco, TX

ok, thats what i thought from what i've read in the other thread. thank you. now this is the unmarked jack above impact, correct? so i also will not need the noise filter cv pot?

Uncle Krunkus · Posted: Mon Oct 31, 2011 1:45 pm Post subject:

Thomas didn't take it out of his design, it was never there.
The pads which give you the option of connecting to the summing point are just that. Pads which have been added at that point. Thomas never entertained the idea of adding these CV inputs, as he knew it could create problems.

I don't know what CVs are referred to on your panel. In Thomas' original design there were NO external CVs at all.

moonagedaydream · Joined: Sep 28, 2011 Posts: 17 Location: Waco, TX

http://www.bridechamber.com/Mega_Percussive_Synth.html

that is the panel i have. honestly i am kinda confused as to what the send and receive jacks are for, i hope the sends are not all cv inputs. does this mean i should leave off the shell cv, is it unsafe as well?

jumunius · Posted: Mon Oct 31, 2011 2:00 pm Post subject:

jumunius · Posted: Mon Oct 31, 2011 2:06 pm Post subject:

moonagedaydream · Joined: Sep 28, 2011 Posts: 17 Location: Waco, TX

well, looks like everything is cleared up for me. Thanks again guys!

Uncle Krunkus · Posted: Mon Oct 31, 2011 3:52 pm Post subject:

jumunius · Posted: Mon Oct 31, 2011 4:54 pm Post subject:

jumunius · Posted: Mon Oct 31, 2011 4:58 pm Post subject:

Also a direct quote from Thomas's write-up at Scott Stites' page:

"Note too that an external control voltage can be added in via J7."

Uncle Krunkus · Posted: Mon Oct 31, 2011 6:15 pm Post subject:

Sorry, yes, you're right.
(I haven't studied these schems since I laid out the PCB, but it's all coming back to me now! Laughing

)
It was the fact that this one simply went to the summing node that made us think an option for the other two summing nodes would be okay. Thomas, however, was adamant that it was a different story for the other summing nodes.

jumunius · Posted: Mon Oct 31, 2011 8:36 pm Post subject:

moonagedaydream · Joined: Sep 28, 2011 Posts: 17 Location: Waco, TX

well, i've decided to add the extra noise cv, and just try remember not to use it. i couldn't stand the empty hole on the panel. so if i'm wiring in a diode, it should go from the noise cv jack, to ground, cathode facing ground? is this correct? and i'm assuming a NTE109 would work fine?

jumunius · Posted: Tue Nov 29, 2011 2:37 pm Post subject:

netpusher · Posted: Sun Jun 10, 2012 9:19 pm Post subject:

Thanks for posting this! I used it to finally finish up my MPS. Though I am not sure why but the Impact section and LED stopped working. Possibly one of my IC's got damaged?

jumunius · Posted: Sun Jun 10, 2012 10:47 pm Post subject:

netpusher · Posted: Sun Jun 10, 2012 11:06 pm Post subject:

Thanks Jim, I will give that try.

netpusher · Posted: Mon Jun 18, 2012 11:46 pm Post subject:

So I finally got a chance to do some trouble shooting on my MPS tonight. I am noticing that my IC4 (4046) is getting really hot! I am wondering if my R88 200K resistor might be bad. Anyone know if that might cause the 4046 to heat up or not?