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

jmagin · Post by **jmagin** » Wed Aug 16, 2017 8:52 pm

Put this together, didn't do it in one go because I didn't have the right pots on hand. Went smoothly otherwise!

(edit: weird, the picture I had uploaded was strangely corrupted)

oilpanic · Post by **oilpanic** » Fri Mar 23, 2018 6:29 pm

waveglider wrote:Here's two photos of the build I just finished so you have a general idea of what goes where and how it looks.

Hello all.
The above image is making me confused.
It states in the first post that the silkscreen for the lm337 is quote "[SILKSCREEN REVERSED ON V1.2 PCBs]"
This is v1.2 right? So then the 337 is mounted in the "reversed" way, but this still works? I have the 1.3 boards, and there the flat side of the chip is facing the two polarized input caps. Im having issues with this and now I start to think that it is actually V1.3 that have the silkscreen in reverse. That would also explain why Im having trouble calibrating the -6V rail. Me and waveglider cant both be correct, and if Im having issues and Waveglider not, then my silkscreen must be incorrect. But maybe this has been sorted out prior in the thread. Ideas?

sceledra · Post by **sceledra** » Fri Mar 23, 2018 7:27 pm

That's a version 1.2 pcb and from the looks of it you have the 10u cap and 337 oriented incorrectly.

negativspace · Post by **negativspace** » Sat Mar 24, 2018 3:33 pm

The instructions are correct for v1.2. You need to flip the regulator. That will fix your -6V rail problem. (Or should, anyway.) And do make sure to flip the electro cap so the + lead is in the grounded pad, although that probably won't be the source of the issue with calibration.

degeneratedsines · Post by **degeneratedsines** » Sat Mar 24, 2018 6:12 pm

Wait, unless I am mistaken he said that he has 1.3 pcb. In this case oilpanic you don't need to reverse anything, just follow the silkscreen orientation. I just had one built last week with 1.3 pcb and it is working perfectly, no issues during calibration. I will try to post some pictures for reference.
Can you tell a little bit more what your problem is for calibration? IIRC, for me the voltage was not moving at first, despite turning the trimmer. But I insisted and it eventually started moving.

degeneratedsines · Post by **degeneratedsines** » Sat Mar 24, 2018 6:22 pm

On the last picture, I highlighted in red the place I put one of my multimeter probe, and I just put the other one on a ground, e.g. Thonkiconn sleeve
I hope this is helping.

degeneratedsines · Post by **degeneratedsines** » Sat Mar 24, 2018 6:24 pm

Btw do NOT mount the jacks like I did otherwise you will run into another stupid issue

sceledra · Post by **sceledra** » Sat Mar 24, 2018 8:50 pm

degeneratedsines wrote:Wait, unless I am mistaken he said that he has 1.3 pcb. .

His pcb clearly reads v. 1.2.

degeneratedsines · Post by **degeneratedsines** » Sun Mar 25, 2018 5:55 am

Let's wait for him to clarify then, but I read his post again and I think I got it right. The pictures are not showing his build but someone else's. and the description he is giving is coherent with 1.3 pcb:

the flat side of the chip is facing the two polarized input caps.

sceledra · Post by **sceledra** » Sun Mar 25, 2018 8:13 am

You might be right, that's what I get for trying to view this on my phone.

workingklass0 · Post by **workingklass0** » Mon Mar 26, 2018 11:51 pm

Can anyone recommend a high-quality replacement for the two 1N4001 diodes on Mouser? Thanks.

monstrinho · Post by **monstrinho** » Tue Mar 27, 2018 12:00 am

workingklass0 wrote:Can anyone recommend a high-quality replacement for the two 1N4001 diodes on Mouser? Thanks.

Mouser has the 1N4001 in stock. I'm not certain why you're asking about a replacement... As far as quality goes, I generally order Vishay diodes and have never had any problems with them.

degeneratedsines · Post by **degeneratedsines** » Tue Mar 27, 2018 11:47 am

I used 750-1N4001-G I think

oilpanic · Post by **oilpanic** » Sat Mar 31, 2018 8:56 am

So to clarify, The Image I posted is not my own, but wavegliders, posted earlier in this thread. The wave glider board must not have been fully functional, but initially I got the impression that it was a correct installation. I mounted my chip like waveglider, but realized the legs where wrong, flipped it around and got a good -6 v.
But the image had me fooled for a while. Interestingly, it would still function somewhat with the chip backwards, but with the unit distorting pretty badly and the skew of the output all different on the in phase and inverted output.

Crisco_Thunder · Post by **Crisco_Thunder** » Thu May 31, 2018 9:24 pm

Hi-

I just put one of these together and am having a weird issue with the output. I get no sound when the output pot at at noon, but do get sound moving either clockwise or counterclockwise. Like I accidentally made an attenuverter

It's the rev1.3 PCB. System is eurorack. 78L12 is jumpered. The pots I'm using are 3 x A50k for the inputs and 1 x B50k for the output.

I was able to calibrate to -6v no problem and able to get the DC offset to 0, though it seemed like that reading would start slowly increasing after I would adjust it. The volume also seems low.

I appreciate any help. I don't know much about electronics. I just follow directions. Thanks!

negativspace · Post by **negativspace** » Thu May 31, 2018 9:49 pm

That's how it works - all is well.

Rex Coil 7 · Post by **Rex Coil 7** » Thu May 31, 2018 11:05 pm

Crisco_Thunder wrote:Hi-

I just put one of these together and am having a weird issue with the output. I get no sound when the output pot at at noon, but do get sound moving either clockwise or counterclockwise. Like I accidentally made an attenuverter

It's the rev1.3 PCB. System is eurorack. 78L12 is jumpered. The pots I'm using are 3 x A50k for the inputs and 1 x B50k for the output.

I was able to calibrate to -6v no problem and able to get the DC offset to 0, though it seemed like that reading would start slowly increasing after I would adjust it. The volume also seems low.

I appreciate any help. I don't know much about electronics. I just follow directions. Thanks!

Counter clockwise gets you negative output ... clockwise provides positive output ... straight up ~noon~ is zero output.

It is how the R.A. Moog discrete transistor mixer is designed, which is the circuit design that Manhattan Analog has adopted for their DTM.

This information isn't in any DTM build documentation? Huh. That's odd. Or perhaps there isn't documentation (maybe this thread is the documentation for the build?).

Crisco_Thunder · Post by **Crisco_Thunder** » Thu May 31, 2018 11:55 pm

Hahahaha. Well I guess the victory lap for assembling it right cancels out the sheepishness for not understanding how it works. Thank you!

Rex Coil 7 · Post by **Rex Coil 7** » Fri Jun 01, 2018 1:29 am

Crisco_Thunder wrote:Hahahaha. Well I guess the victory lap for assembling it right cancels out the sheepishness for not understanding how it works. Thank you!

Right on man! There's nothing like that ~feeling~ of satisfaction and pride when something you built ... with your own friggin hands ... actually WORKS! Yea?

Even though I've been building ~junk~ for many (many) years, it never fails to produce that same feeling ... you just want to clench your fist, and pull down a solid "yes!" when it powers up, LEDs light up, and sound comes out like it is designed to. It still feels fresh and new, every time!

Go for it dude .......

pppier · Post by **pppier** » Fri Jun 01, 2018 2:50 am

hi all
I have much more fun in running the LM337 at -4,7V
having the squared spike i like
what do you think?

Rex Coil 7 · Post by **Rex Coil 7** » Fri Jun 01, 2018 1:26 pm

pppier wrote:hi all
I have much more fun in running the LM337 at -4,7V
having the squared spike i like
what do you think?

I think (since you've asked) that an audio or video demo would be great! If trimming the DTM makes for a fairly wide set of sound changes, then I believe exploring the idea of bringing that particular trimmer out to the front panel for realtime ~tweeking~ would be worth doing. In other words, replace that particular on-board trimmer with a panel mounted pot.

VCA/CP3 6 channel mixer: As soon as my wife and I look at our monthly budget for this month, I'll be ordering 4 boards. One is already designed in to a 6 channel mixer panel I've designed that uses a VCA on each input channel. So 6 VCAs feeding 6 input channels that sum before hitting the discrete transistor core.

Here's the roughed out panel (it's in 5U) .....

So imagine putting a VCA in front of each input channel, and having 6 channels. That way you can use a joystick or wheels or expression pedal or LFOs or Env Gens (or a combination of all of those) to control the input levels of each single channel on the fly.

MOUSER PROJECT: Also, I've just about completed a Mouser Project for this PCB. When completed I'll be glad to share it. As I type this, I can see I'll need to make two Mouser Projects ... one for 12v and another for 15v. The Project files WILL NOT include the channel pots or the master output pot. I'll leave those to the individual builder to add (since everyone may wish to do their own recipes).

On third thought, I suppose I can make up a Mouser Project that will coincide with the Euro panel that Manhattan Analog offers (which will include the PCB mounted Alpha pots) so that way all a person will have to do is order the PCB and the module panel from Member *negativspace (Manhattan Analog) and then order the Mouser project and wait for it all to show up ... then build the DTM!!!

Rex Coil 7 · Post by **Rex Coil 7** » Thu Jun 07, 2018 6:29 pm

I just ordered (and paid for) 3 PCBs, sent to Yuma, Az. .... this will be fun!

negativspace · Post by **negativspace** » Fri Jun 08, 2018 6:03 am

And I just packed them up.

I'll have them out this afternoon. Thanks.

Rex Coil 7 · Post by **Rex Coil 7** » Mon Jun 11, 2018 2:31 pm

negativspace wrote:And I just packed them up.

I'll have them out this afternoon. Thanks.

3 boards received, all is well.

negativspace · Post by **negativspace** » Mon Jun 11, 2018 8:21 pm

MUFF WIGGLER

MUFF WIGGLER

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