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marvkaye
Joined: Mar 14, 2011
Posts: 225
Location: Fla
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 Posted: Tue Oct 18, 2011 6:33 am Post subject:
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| TheProf wrote: |
If anyone knows of a good cheap source for the 'Tefzel' wore that will work in my 'Strip 'n Wrap' bit, (the ordinary 'Kynar' has problems, I'd be very happy.
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Cheap...Tefzel... two words that don't often collide in the same sentence, almost an oxymoron. Just the same, what gauge(s) are you looking for?? I have a great electronics surplus place in Orlando where I buy almost all of my wire... I suspect they may have what you need.
<marv> |
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moonagedaydream
Joined: Sep 28, 2011
Posts: 17
Location: Waco, TX
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| Posted: Mon Oct 31, 2011 12:53 pm Post subject:
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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.  are you guys talking about additional mods? or are these things that are marked on the panel that shouldnt be there... |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 1:28 pm Post subject:
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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!) |
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moonagedaydream
Joined: Sep 28, 2011
Posts: 17
Location: Waco, TX
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| Posted: Mon Oct 31, 2011 1:42 pm Post subject:
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| 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? |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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| Posted: Mon Oct 31, 2011 1:45 pm Post subject:
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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.
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What makes a space ours, is what we put there, and what we do there. |
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moonagedaydream
Joined: Sep 28, 2011
Posts: 17
Location: Waco, TX
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| Posted: Mon Oct 31, 2011 1:50 pm Post subject:
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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? |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 2:00 pm Post subject:
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| Uncle Krunkus wrote: | | Thomas didn't take it out of his design, it was never there. |
Sorry, yes, thanks for the clarification.
| Quote: | | I don't know what CVs are referred to on your panel. In Thomas' original design there were NO external CVs at all. |
There's a Shell CV towards the bottom right of Sheet 3 of the schematics. But there's no Noise or Impact CV in the schematics.
-Jim |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 2:06 pm Post subject:
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| moonagedaydream wrote: | | honestly i am kinda confused as to what the send and receive jacks are for, i hope the sends are not all cv inputs. |
See Sheet 4 of the schematics. The idea is that you can process each voice (impact, shell, noise) separately before mixing them in the MPS. The design calls for switching jacks on the receiving end so that your signals bypass their respective send/receive jacks unless you have something plugged in.
A lot of people seem to have ignored these. Since panel space is not an issue for you, they seem useful enough to me to keep. |
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moonagedaydream
Joined: Sep 28, 2011
Posts: 17
Location: Waco, TX
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| Posted: Mon Oct 31, 2011 2:24 pm Post subject:
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| well, looks like everything is cleared up for me. Thanks again guys! |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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| Posted: Mon Oct 31, 2011 3:52 pm Post subject:
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| jumunius wrote: | There's a Shell CV towards the bottom right of Sheet 3 of the schematics. But there's no Noise or Impact CV in the schematics.
-Jim |
Even the shell CV is a switch which controls whether the impact or noise sections are going to modulate it. It is not meant to be used as an external CV input.
I think Thomas put the send/recieve jacks there so you could send your CVs to an external VCA, VCF etc. and thereby have CV control of all three sections. Which, by the way, is a pretty good idea. As long as you have some external VCAs, VCFs, etc. to patch in.
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What makes a space ours, is what we put there, and what we do there. |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 4:54 pm Post subject:
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| Uncle Krunkus wrote: | | Even the shell CV is a switch which controls whether the impact or noise sections are going to modulate it. It is not meant to be used as an external CV input. |
Hmm, but there's a switching jack (J7) depicted on Sheet 3 of the schematics (and also listed as one of 4 switching jacks in the BOM). |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 4:58 pm Post subject:
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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." |
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Uncle Krunkus
Moderator
Joined: Jul 11, 2005
Posts: 4761
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1
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| Posted: Mon Oct 31, 2011 6:15 pm Post subject:
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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!  )
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.
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What makes a space ours, is what we put there, and what we do there. |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Mon Oct 31, 2011 8:36 pm Post subject:
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| Uncle Krunkus wrote: | 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! )
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. |
Indeed, I think most people would have trouble remembering how to use the finished 18-knob module in a period of a couple years; if I wasn't working on this 2 weeks ago I wouldn't have much hope of remembering the schematics.  |
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moonagedaydream
Joined: Sep 28, 2011
Posts: 17
Location: Waco, TX
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| Posted: Tue Nov 29, 2011 1:04 pm Post subject:
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| 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? |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Tue Nov 29, 2011 2:37 pm Post subject:
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| moonagedaydream wrote: | | 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? |
Only the sleeve terminal should go to ground if you want it to do anything. If you want to add the jack, you should do something more like connecting the noise CV jack (tip) to the diode, and the cathode end of your diode to the noise CV summing point (I think it's the junction around R64 but I may be misremembering -- the noise frequency pot connects here via resistor). The idea would be to prevent negative voltages from getting through. The result will be that the lower swings of CVs (like the bottom half of a sine LFO) gets flattened.
Don't know about the NTE109 specifically.
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netpusher
Joined: Sep 08, 2010
Posts: 10
Location: Northern California
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| Posted: Sun Jun 10, 2012 9:19 pm Post subject:
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| 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? |
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jumunius
Joined: Apr 19, 2010
Posts: 346
Location: San Francisco, CA
Audio files: 13
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| Posted: Sun Jun 10, 2012 10:47 pm Post subject:
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| netpusher wrote: | | 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? |
Probably just an intermittent wiring connection, header issue, etc. LED and impact are fairly exclusive. I'd check all your wiring first. Easiest thing to do is to lightly fiddle with your impact wires while powered on and see if that makes a difference, then go from there.
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-Jim |
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netpusher
Joined: Sep 08, 2010
Posts: 10
Location: Northern California
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| Posted: Sun Jun 10, 2012 11:06 pm Post subject:
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| Thanks Jim, I will give that try. |
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netpusher
Joined: Sep 08, 2010
Posts: 10
Location: Northern California
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| Posted: Mon Jun 18, 2012 11:46 pm Post subject:
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| 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? |
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