[IN STOCK] DTM: Moog CP3-type discrete mixer PCB, Euro panel

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Rex Coil 7
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Post by Rex Coil 7 » Tue Jun 12, 2018 7:42 am

I'm building all three boards for use in a 15v system. I think I had read somewhere amongst the 30-odd pages of this thread (which I've read twice now) that the ferrite beads are not required, and that they may be replaced ... can't recall if their replacements are resistors or solid wire links.

Anyhow, if they may be replaced with links or resistors, what is the beads' purpose in the first place? I'm not a highly educated or experienced person when it comes to electronic design (relatively speaking).

Thank you.
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Post by negativspace » Tue Jun 12, 2018 9:57 am

The purpose there is to filter out high frequency noise on the power rails... small resistors (~10 ohm) should serve a similar purpose. Wire links obviously won't, but that may or may not even be a problem depending on your individual environment.

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Post by Rex Coil 7 » Tue Jun 12, 2018 10:23 am

negativspace wrote:The purpose there is to filter out high frequency noise on the power rails... small resistors (~10 ohm) should serve a similar purpose. Wire links obviously won't, but that may or may not even be a problem depending on your individual environment.
Ok, thanks. Hmmm .... choosing beads is a bit of a challenge, as Mouser offers various "amperage" ratings for the same package (and I've no clue which one to select).

Power? I'm using a bus bar system with a dedicated ground bus bar (different from the 0v bar). So I have a "five bar system" (pos, neg, 5 volt, 0v, and ground). The custom chassis (panels) and jack shields are tied straight to the ground bar ...the ground bar is connected directly to Earth on the primary side of the transformer where the ground wire in the mains power cable is connected. Module panels have their jack shields tied as well.

It may not be the ~perfect~ set up but it's the best I know how to do within my budget, education, and skill set. So hopefully I've done what I can to keep the noise, cross talk, and functionality as optimal as practical. At least as much so within the design confines given to us with our unbalanced synthesizers.

Maybe I'll use sockets to install wire links on the boards, if that doesn't work out I can exchange the resistors for resistors, and if that doesn't work out I can swap the resistors out for the ferrite beads .... soldering in whichever solution works out best for a permanent installation.

Or .... I can just go with the stinkin' ferrite beads from the git-go
... if I can figure out which part number to buy!!

:despair:

Image

Image

Image
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Post by negativspace » Tue Jun 12, 2018 10:26 am

These are the ones I use. (Mouser)

623-2743001112LF

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Post by Rex Coil 7 » Tue Jun 12, 2018 1:51 pm

negativspace wrote:These are the ones I use. (Mouser)

623-2743001112LF
WHAT!!! SERIOUSLY?? Those are THIRTEEN CENTS EACH!!! And each board needs TWO of them! SHEES!!! I mean, c'mon man!

Ok, forget it ... I'm sending the boards back ... this is just gonna cost too much to build. :roll:

:lol: :party: :tu:

Goofballing aside, thanks a lot for the link ... really helpful! Between working out Mouser projects for these boards and the Oakley Dual VCA boards (I'm using four of those) I got my Ps & Qs all afunk ... I'll be posting the Mouser project here in this thread after I get it all smoothed out. I'll PM you with it first so you can give it a look. I'm sure some folks will find it helpful.

Or not. :despair:

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Post by Made In Machines » Mon Oct 01, 2018 4:10 am

Please could someone provide a fool proof BOM I can just copy and paste into something like the mouser BOM tool. I'm never to all of this and unfamiliar with electronics parts. Thanks

https://www.mouser.co.uk/Bom/CopyPaste

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Post by negativspace » Wed Oct 03, 2018 5:03 am

Rex Coil 7 wrote:
negativspace wrote:These are the ones I use. (Mouser)

623-2743001112LF
WHAT!!! SERIOUSLY?? Those are THIRTEEN CENTS EACH!!! And each board needs TWO of them! SHEES!!! I mean, c'mon man!
:omg:

Kidding aside... you can replace them with very low-value resistors (10 Ohm) or even wire links if the spirit moves you, or if you're literally using every last penny to your name to build this module and can't scare up another quarter. :hihi:

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Post by Sleipnir » Thu Oct 11, 2018 4:05 am

Thought I’d put up a pic of a finished (and working) DTM V1.3 board, built using the Synthcube kit.
It was a bit confusing, since the 1.3 pcb doesn’t have any of the electrolytic capacitors labeled except the optional one (and SynthCube supplies a 10nF cap for the non-power filter cap).
Do love the DTMs. Much prefer the layout to the S&TG .MIX :sb:
Image
I don’t know if it was because the kits had sat in my todo pile for a few months, or the way they were stored previously, but both kits were really hard to solder. The pads were black, and I thought it was some kind of fancy new material, but turned out to be oxidation. Had to hit it with some 2000 grit sandpaper and lay on a ton of extra flux.

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Post by negativspace » Thu Oct 11, 2018 6:04 am

Yeah, the ROHS silver-finished boards will tarnish after a while.

Best storage procedure is to keep them in air-tight sealed containers (tupperware/similar, or even a good zip bag, bonus points for using silica packets) and if they do tarnish, a bit of Tarn-X or your (grandmother's) preferred silver tarnish remover will bring them back around in a matter of seconds.

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Post by BananaPlug » Thu Oct 11, 2018 7:28 am

The green scrubby stuff, sold near sponges, is good for lightly removing oxidation on pcbs.

I love the DTM in my small portable system. What’s working well is to patch the output to an attenuator and patch that to my output module for line out. Adjusting attenuator lets me tweak how much crunch goes into the mix. Lower mix plus less attenuation is clean. Higher mix with attenuation for more “character” at same overall level.
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Post by Rex Coil 7 » Thu Oct 11, 2018 9:26 am

Sleipnir wrote: ...I don’t know if it was because the kits had sat in my todo pile for a few months, or the way they were stored previously, but both kits were really hard to solder. The pads were black, and I thought it was some kind of fancy new material, but turned out to be oxidation. Had to hit it with some 2000 grit sandpaper and lay on a ton of extra flux.
Sand paper leaves grit embedded in the soft traces and pads. Even crocus clothe will leave grit behind. Sand paper uses glue to adhere the grit to the paper (the glue sticks to the grit as well), so that leaves grit and glue embedded into the traces and pads.
negativspace wrote:Yeah, the ROHS silver-finished boards will tarnish after a while.

Best storage procedure is to keep them in air-tight sealed containers (tupperware/similar, or even a good zip bag, bonus points for using silica packets) and if they do tarnish, a bit of Tarn-X or your (grandmother's) preferred silver tarnish remover will bring them back around in a matter of seconds.
BananaPlug wrote:The green scrubby stuff, sold near sponges, is good for lightly removing oxidation on pcbs.
I use pencil erasers. The rectangular ones that are a funny shade of pink/red. Pencil erasers are abrasive and work very well for cleaning off PCB traces and pads.

For the through holes, I use these little round brushes made for flossing between your teeth. They have wound-wire in the center with brush hairs spiraling out, just like a bottle brush or any other brush made that same way. Those "flossing" brushes are small enough to fit into through holes and work well enough. They're not abrasive, but they work better than using nothing at all, that's for damned sure!

Maybe some of gramma's silver polish or pre-tinning paste or soldering flux applied to the flossing brush may make it more effective.
BananaPlug wrote:I love the DTM in my small portable system. What’s working well is to patch the output to an attenuator and patch that to my output module for line out. Adjusting attenuator lets me tweak how much crunch goes into the mix. Lower mix plus less attenuation is clean. Higher mix with attenuation for more “character” at same overall level.
I've purchased several Oakley Dual VCA boards (3) which are to be used as input channel VCAs for the DTM. I'll be modifying the basic layout to create a six channel input stage of the DTM which will be fed signals from the six Oakley VCAs. This way I can use automated or manual means to control the amount of distortion on each input channel. The output is sent to the filter array. Then the filter array output is sent to another 4 channel Oakley VCA/DTM ensemble used as a pre-output-VCA mixer. Ultimately the signal exits the synth from there.

Here's a screenshot of the Front Panel Express panel I have worked up. It's about 98% finished. The orange graphics are "military orange", the same as the instrument cluster backlighting that is used in military fighter jets, helicopters, and strategic aircraft. The US Military has done many studies regarding attention span, depth of focus, and eye fatigue which produced this orange color for their lighted instruments and computer heads-up-displays. This screenshot does not do the panel any justice at all, the orange graphics are a much brighter hue of orange than this image depicts!

Image

This panel houses 3 Oakley Dual VCA boards (total of six VCAs), one 6ch DTM board, and one CGS "Real Ring Modulator" board that I've customized by using 3mm blue water clear LEDs in the diode ring.

:tu:
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Post by Sleipnir » Thu Oct 11, 2018 11:21 am

Damn, I didn’t even think of silver polish. Next time (or the eraser trick).
They were shrink wrapped in the Synthcube boxes, but I guess not sealed enough.
Rex: I gave them a nice isopropyl bath after, so hopefully no grit/glue. The 2000 grit is so fine, I couldn’t see anything under 40x magnification.

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Post by Rex Coil 7 » Thu Oct 11, 2018 12:19 pm

Sleipnir wrote:Damn, I didn’t even think of silver polish. Next time (or the eraser trick).
:tu:
Sleipnir wrote:Rex: I gave them a nice isopropyl bath after, so hopefully no grit/glue. The 2000 grit is so fine, I couldn’t see anything under 40x magnification.
:tu:

Actually, the grit doesn't pose a mechanical problem or challenge, it's more about how it contaminates the surface making it difficult to solder ... which is something you confirmed was happening (presented below) .....
Sleipnir wrote:I don’t know if it was because the kits had sat in my todo pile for a few months, or the way they were stored previously, but both kits were really hard to solder. The pads were black, and I thought it was some kind of fancy new material, but turned out to be oxidation. Had to hit it with some 2000 grit sandpaper and (still) lay on a ton of extra flux.
Note that I added the red colored word "still" to emphasize my point.

:despair:
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Guide?

Post by defalut » Fri Jan 04, 2019 4:30 pm

Hi,
Is there a build instruction somewhere for this module or is it self-explaining even for a n00b?
Got the pcb+panel and the components are on the way.. :banana:

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Re: Guide?

Post by Rex Coil 7 » Fri Jan 04, 2019 5:57 pm

defalut wrote:Hi,
Is there a build instruction somewhere for this module or is it self-explaining even for a n00b?
Got the pcb+panel and the components are on the way.. :banana:
I can't recall if there are actually step by step build instructions. But if there are not any, it's no different than building any small circuit board.

** Start by sorting the parts and making sure everything matches the bill of materials (aka "BOM").
** Begin with soldering the lowest parts on the board. By "lowest" I mean the parts that lay the lowest against the board. Usually those are the resistors.
** Then work your way up with taller parts .... the ones that stick up farther. These are usually the capacitors, and any chip sockets you may decide to use.

Just continue plogging away at it. Lastly solder any wires that go to pots and jacks.

Obviously you'll need to drill any holes in whatever panel you're using, as well as mount any panel-mounted parts (pots, switches, jacks).

So you build the board first. Mount any panel mounted controls to the panel. Then lastly wire the board to the panel.


That's pretty much the general method of building most any of this stuff. There are countless videos and websites that cover this type of construction found all over the internet. Everyone develops their own methods and styles of construction after they've built a few things. I certainly have my own ways of doing things, that's for sure.

As far as a 1, 2, 3, ... etc ... step by step build document dedicated to this exact device ... I'm not sure if one exists. Perhaps someone else will come along here and provide better information for you than I have.

:tu:
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Post by synthetek » Fri Jan 04, 2019 9:49 pm

Read through this thread, it is the build doc. There are some screen print errors on some pcbs , there may be a trace cut necessary? or that might have been on the VCA? Read this thread before you start.

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Post by Rex Coil 7 » Fri Jan 04, 2019 11:38 pm

synthetek wrote:Read through this thread, it is the build doc. There are some screen print errors on some pcbs , there may be a trace cut necessary? or that might have been on the VCA? Read this thread before you start.
Well, I have to wonder if that poster wasn't actually looking for a few pages of instructions rather than THIRTY TWO PAGES OF THIS THREAD ... which is at 791 posts if this one by me is included.

:tu:
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Post by defalut » Sat Jan 05, 2019 1:19 am

Rex Coil 7 wrote:
synthetek wrote:Read through this thread, it is the build doc. There are some screen print errors on some pcbs , there may be a trace cut necessary? or that might have been on the VCA? Read this thread before you start.
Well, I have to wonder if that poster wasn't actually looking for a few pages of instructions rather than THIRTY TWO PAGES OF THIS THREAD ... which is at 791 posts if this one by me is included.

:tu:
That is correct. :oops:
I tried to read the whole thread, i really did. But suffering from sleep deprivation due to added family members and so on and so forth, i did not manage to get very far. I also tried to search for it.

Thanks for the summary, that helps a lot!
For the rest of my build i will try to find answers in the thread. I´ve managed to find the mouser cart and what to replace a missing 1n401 (or something) with, so the rest should be no problem. Cheers!

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Post by synthetek » Sat Jan 05, 2019 7:07 am

Rex Coil 7 wrote:
synthetek wrote:Well, I have to wonder if that poster wasn't actually looking for a few pages of instructions rather than THIRTY TWO PAGES OF THIS THREAD ... which is at 791 posts if this one by me is included.

:tu:
He probably was looking for a build doc like a lot modules have but for this one the official build doc happens to be this thread. Since there are some errors on some PCB revisions and other useful info it's advisable to read it or at least search the thread if you are in doubt about anything.

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Post by defalut » Sat Jan 05, 2019 4:41 pm

synthetek wrote:
Rex Coil 7 wrote:
synthetek wrote:Well, I have to wonder if that poster wasn't actually looking for a few pages of instructions rather than THIRTY TWO PAGES OF THIS THREAD ... which is at 791 posts if this one by me is included.

:tu:
He probably was looking for a build doc like a lot modules have but for this one the official build doc happens to be this thread. Since there are some errors on some PCB revisions and other useful info it's advisable to read it or at least search the thread if you are in doubt about anything.
Yes, that´s true aswell. I found a few very nice and detailed instructions with other Manhattan modules, so i figured (or hoped, rather) that i could find a similar one. But i will manage, with the summary recieved and a few images collected it´s going to be alright. I´ll skim though the thread before i start the build and take notes too.. Thanks guys. :)

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Post by defalut » Thu Mar 21, 2019 7:21 pm

Hey,
Looked and searched but it's Hard to find how to trim the dtm properly.

What i did was set inputs 1-3 to max, ant output to the middle.

Then i put a cable in output 1, measured, and tweaked the blue small pots till i got 5volts. Repeated w 2+3 w same resultat.

Is that enough, or did i fudge it Up?

If false, how should i do?

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Post by woodster » Sat Mar 23, 2019 11:44 am

For calibration, Have a look at the bottom of the first post in this thread.

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Post by defalut » Sat Mar 23, 2019 3:02 pm

woodster wrote:For calibration, Have a look at the bottom of the first post in this thread.
Of course! How could i have missed that? Thanks!
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Post by raccoonboy » Thu Apr 11, 2019 3:51 am

Thinking of doing this as a DIY.

From previous posts, I found this mouser cart.

https://eu.mouser.com/ProjectManager/Pr ... ee01d1e641

The Ferrite beads are obsolete, apparently I can use a resistor or something instead but is there a similar ferrite bead I can use instead? I tried searching but no idea how to use mouser or what I'm looking for.

Also, item 512-1N4001 is missing and I have no idea what it was :\

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Post by Agawell » Thu Apr 11, 2019 3:55 am

1N4001 is a diode, for both this and the ferrite beads go to the actual product page that's missing and there should be a show similar button - compare the datasheets - if they match you are good to go

if they don't try to find the closest and check back here

quick hint on searching - only search on the last bit of the code - the first part is a mouser category code

I found quite a few variations of "1n4001"
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