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fitzcarraldo
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Post by fitzcarraldo » Sun Feb 17, 2019 8:43 am

I have finally found the time to complete my Deckard. While it’s alive and making sounds I do have a problem with the second oscillator. It either remains quiet or emits far too loud bursts of either distorted or highly resonant sounds.

Here’s a video, in which I play with Osc B on to start with and then with Osc B switched off:
vimeo.com/317792320

I have removed voice cards and tried one at the time with the same results. Unless I made the same mistake on all 8 voice cards I think they can be ruled out as the culprit.

Any ideas where to look/concentrate my debugging?

Please don’t refer me to Facebook, I have no intentions of joining up. Not even for the sake of this synth.

Thanks!


Edit:
Here’s a second video, that might illustrate the problem better:
vimeo.com/317794397

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Post by jimfowler » Mon Feb 18, 2019 9:37 am

It's been a while but I was able to resolve some similar odd behavior by re-flashing the firmware and re-calibrating.

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Post by mOBiTh » Mon Feb 18, 2019 12:16 pm

jimfowler wrote:It's been a while but I was able to resolve some similar odd behavior by re-flashing the firmware and re-calibrating.
yep, it's important to do the deep calibration, not the shallow one! :hihi:

fitzcarraldo
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Post by fitzcarraldo » Mon Feb 18, 2019 4:48 pm

Thanks for the tip. I did try that however.

I have also tried various versions of the firmware (1.2.5, 1.2.8 and 1.2.9).

Same result every time.

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Post by c0ntr4d1ct10n » Fri Mar 01, 2019 1:49 am

So Ive just read somewhere that the prebuilt version is smaller in depth and lighter than the diy version because it uses more smd components?

Are there smd components on the prebuilt version that are significantly more difficult to solder than what most people are capable of? I'm not trying to be pretentious but i've only been soldering for 6 months and have found that after a number of Mutable Instruments builds, I have gotten over my shaky hand condition and I now much prefer smd soldering than through hole (I hate having to cut the legs each time they get in the way). Maybe I am just a weirdo.

The only things I have trouble soldering by hand are those legless quad pack chips (which I think are meant to be soldered using an oven).

I'm just thinking would an option for the mostly smd pcbs be cheaper to manufacture?

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Post by JanneI » Fri Mar 01, 2019 2:04 am

c0ntr4d1ct10n wrote:So Ive just read somewhere that the prebuilt version is smaller in depth and lighter than the diy version because it uses more smd components?

Are there smd components on the prebuilt version that are significantly more difficult to solder than what most people are capable of? I'm not trying to be pretentious but i've only been soldering for 6 months and have found that after a number of Mutable Instruments builds, I have gotten over my shaky hand condition and I now much prefer smd soldering than through hole (I hate having to cut the legs each time they get in the way). Maybe I am just a weirdo.

The only things I have trouble soldering by hand are those legless quad pack chips (which I think are meant to be soldered using an oven).

I'm just thinking would an option for the mostly smd pcbs be cheaper to manufacture?
There is no SMD diy option, DIY is through-hole only.

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Post by c0ntr4d1ct10n » Fri Mar 01, 2019 10:48 am

JanneI wrote:
c0ntr4d1ct10n wrote:So Ive just read somewhere that the prebuilt version is smaller in depth and lighter than the diy version because it uses more smd components?

Are there smd components on the prebuilt version that are significantly more difficult to solder than what most people are capable of? I'm not trying to be pretentious but i've only been soldering for 6 months and have found that after a number of Mutable Instruments builds, I have gotten over my shaky hand condition and I now much prefer smd soldering than through hole (I hate having to cut the legs each time they get in the way). Maybe I am just a weirdo.

The only things I have trouble soldering by hand are those legless quad pack chips (which I think are meant to be soldered using an oven).

I'm just thinking would an option for the mostly smd pcbs be cheaper to manufacture?
There is no SMD diy option, DIY is through-hole only.
I know that. Just wondering what the reason is for why there is no smd diy option.

fitzcarraldo
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Post by fitzcarraldo » Thu Mar 07, 2019 8:20 am

Sorry for the bump, but does nobody have any ideas what else I could try for my problem above?

Thanks!

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Post by Chrutil » Thu Mar 07, 2019 2:17 pm

fitzcarraldo wrote:Sorry for the bump, but does nobody have any ideas what else I could try for my problem above?

Thanks!
From the videos it's not clear to me if this happens due to some external stimuli, like aftertouch - or if it is random and happens on and off if you just send MIDI note on and let it drone for a while with no other MIDI events.
It is also not clear to me that it happens on all voices. Looks to me like voice 2 is the main culprit, in particlular on the second video you hear the noise as soon as voice 2 is on, but there's not enough video to completely determine that.

An oscilloscope would be very useful tracking this down.
But best is to gather more evidence before even opening up the machine.
You said it happens on all voice cards - does it happen on all slots? The video seems to show it on slot 2 only.
Track this down further, and see if you can figure out if there is a particular control CV that is boosted, like VCF or Level, for example.
One thing I would try is to see if you can monitor the output of a voice card edge connector on the motherboard with an oscilloscope to see if these spikes are present from each voice, or if they are introduced after the voices are mixed - seems like before since it only affects voices B, but who knows. Check the schematics and look at pin 1 and 2 from the edge connector.

I would also monitor VCF-A vs VCF-B on the voice card connector to see if there are spikes in the incoming filter CV, and also look for other CV's that you think could be responsible for causing that sound if they spiked - if it happens to all voice card slots then it's probably either one of the incoming signals that are common to all cards - or after the voice card outputs, but before the A and B channels are mixed.

Somewhere in the signal path this noise is introduced, and tracing it to a CV path or audio path would be a great first step.

Finally, as you know, unfortunately the Black Corporation DIY build discussions seems to be happening on Facebook much more than Muff's.
With Facebook's focus on the "here and now" there is very little archive for the future and even though you may not want to sign up for Facebook I would advice you to sign up anyway.
Remember, you don't have to sign up as yourself, just create a "CompartmentalizedIdentity" or "DeckardsDreamBuilder" user with no friends and sign in with the browser set to 'private' or 'incognito' mode.

Keep us posted!

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Post by fitzcarraldo » Mon Mar 11, 2019 5:59 am

Thanks Chrutil for all the pointers. I don’t think I will have time before the next weekend to start debugging again. I will let you know in any case about progress.

Cheers

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campacasa
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Expander kit

Post by campacasa » Tue Mar 12, 2019 4:17 pm

Communication with Black Corporation seems difficult, not receiving replies to mails I'm sending them through their website's contact form.

Does anyone know more about the Expander kit? Almost one year ago I have ordered one (together with the DDRM kit, which I have received end of last year). The revised version of the Expander built version is visible on the website, the kit still is the old one. But I had understood that the kit also will become like the new version. Then I'm also interested in a BOM for the Expander kit. Still needing to order a number of parts for the DDRM, which I'd like to combine with the Expander.

Thanks,
Peter

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Chrutil
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Re: Expander kit

Post by Chrutil » Tue Mar 12, 2019 5:58 pm

campacasa wrote:Communication with Black Corporation seems difficult, not receiving replies to mails I'm sending them through their website's contact form.

Does anyone know more about the Expander kit? Almost one year ago I have ordered one (together with the DDRM kit, which I have received end of last year). The revised version of the Expander built version is visible on the website, the kit still is the old one. But I had understood that the kit also will become like the new version. Then I'm also interested in a BOM for the Expander kit. Still needing to order a number of parts for the DDRM, which I'd like to combine with the Expander.

Thanks,
Peter
I think you know about as much as anyone else.
I preordered the Expander in January last year and the Kijimi in March last year. Both over a year ago.
The Expander was delayed but now at least the prebuilt seems to be shipping and I do expect the pcb's to show up at some point, hopefully soon, but I haven't seen any information about it.

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Post by sduck » Tue Mar 12, 2019 8:10 pm

The last I heard was that they were going to start shipping the expander PCBs right after NAMM. That was almost 2 months ago, and still nothing.
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Post by JanneI » Wed Mar 13, 2019 4:10 am

They basically stopped sharing info about their schedule before NAMM. Only explanation for this behavior (IMHO) is that there's something wrong with the design or manufacturing process, hence the undetermined delay. I still believe that it's BC's intension to deliver everything eventually, but when that day is, nobody knows. Might take another year, who knows..

One batch of pre-build expanders have been send to customers and at least REV2 users state that expander works fine. REV1 users have been reporting issues. Second batch of expanders are in hold, I think? DIYers don't have BOM, expander enclosures showed up but with mounting holes 5mm off :eek: :mad: :bang: Well, new ones will be sent and while there's no BOM yet this doesn't really matter.

If your fingers itch to build something, don't wait these. My 5 cents..

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campacasa
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Post by campacasa » Wed Mar 13, 2019 3:56 pm

Thanks for the Expander replies. So I'm not alone and it's not just me who may have missed something.

Then I'd better just order the missing parts for my DDRM and will hope that the Expander finally will arrive one day (and order parts again).

- Peter

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campacasa
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Expander kit

Post by campacasa » Thu Mar 14, 2019 4:21 pm

Well, surprise, surprise... Have I been too impatience or is this just coincidence. Today I received a mail from Black Corporation: "The DD Expander DIY kits WILL go out next week. Waiting on Roman for the BOM, which will hopefully also be out by then."

They also mention about a newsletter to come out shortly.

Now I might actually wait a little to make that combined component order.

Best regards,
Peter

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Post by synthcube » Thu Mar 14, 2019 4:30 pm

here's hoping!!
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fitzcarraldo
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Post by fitzcarraldo » Sat Mar 16, 2019 9:57 am

Anyone based in London who would like to help me debug my DDRM build? See the issues I’m having in my previous post here here

I was planning to try it again today, following some of Chrutil’s helpful suggestions, but I realise I simply don’t have the experience and it could potentially take me forever and life’s currently too hectic as it is...

Oh and just to be clear, happy to pay, not expecting anyone to do this as a favour.

Please PM me if you’re up for it.

Thanks!

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Post by ultravox » Sat Mar 16, 2019 11:12 am

fitzcarraldo wrote:Anyone based in London who would like to help me debug my DDRM build? See the issues I’m having in my previous post here here

I was planning to try it again today, following some of Chrutil’s helpful suggestions, but I realise I simply don’t have the experience and it could potentially take me forever and life’s currently too hectic as it is...

Oh and just to be clear, happy to pay, not expecting anyone to do this as a favour.

Please PM me if you’re up for it.

Thanks!
Hi fitzcarraldo,
To my ears this sounds like a reversed IC (possibly a V2164). My first suggestion is leave the voice cards in their current locations and run a full calibration of all 8 cards.

Turn on all four oscillator switches. Move the Mix I / II slider to position "I" then play only single notes (not intervals, or triads). Listen for the distorted sound while watching the OLED to see which oscillator is the culprit. Be sure to cycle through all the voice cards in case there's more than one with an issue.

Then move the Mix slider to position "II" and repeat the above step.

When you find the card(s) with trouble, pull them out and look for reversed or improperly seated IC's. Note: a reversed V2164 needs to be replaced because it will be fried.
This means nothing to me... Oh, Vienna!

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Post by fitzcarraldo » Sun Mar 17, 2019 8:23 am

Thanks ultravox,

It’s definitely not the voice cards.

I did spend some more time after all and am coming closer to the problem. But with my non-existent electronics skills I feel that I’m at the end of what I can do.

The basic problem is that the signal from Osc II is too hot and distorted. Again, if I listen to the raw signal from the card connector it is all fine. Osc I and II have the same volume and are both clean. The voice cards are perfectly fine (well, at least 7 of them are, but that’s a different issue).

I followed the signals and after the two electrolytic caps C288 and C289 both Mix 1 and Mix 2 are similarly strong and sound clean.

Then however after the two resistors (R220 for Mix 1 and R228 for Mix 2) the signal is massively attenuated for Mix 1, but only slightly attenuated for Mix 2. By massively attenuated I mean if you listen to the input signal at R220 at normal volume, you barely hear the output signal.

I have no idea which one of the two is right, Mix I is getting attenuated too drastically I believe, but then again, I am having problems with Mix 2 in the end.Should that 30k resistor really attenuate the signal that much?

By the way, I have swapped out all the ICs on the mother board, one by one to no avail.

If one of you has some more ideas I will give it another try, but I believe at this point I need someone with actual electronics knowledge to look at it.

Thanks, as always!

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Post by Techman » Mon Mar 18, 2019 3:42 pm

fitzcarraldo wrote:
I followed the signals and after the two electrolytic caps C288 and C289 both Mix 1 and Mix 2 are similarly strong and sound clean.

Then however after the two resistors (R220 for Mix 1 and R228 for Mix 2) the signal is massively attenuated for Mix 1, but only slightly attenuated for Mix 2. By massively attenuated I mean if you listen to the input signal at R220 at normal volume, you barely hear the output signal.

I have no idea which one of the two is right, Mix I is getting attenuated too drastically I believe, but then again, I am having problems with Mix 2 in the end.Should that 30k resistor really attenuate the signal that much
I would check your soldering around R228, C325 & R226 and make sure they are the correct values. Also check the soldering to the socket for IC57. If you still have problems then PM me. I’m in Barnet with a working DDRM. I’m sure between us we can sort this.

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Post by Chrutil » Mon Mar 18, 2019 4:06 pm

fitzcarraldo wrote:Thanks ultravox,

The basic problem is that the signal from Osc II is too hot and distorted. Again, if I listen to the raw signal from the card connector it is all fine. Osc I and II have the same volume and are both clean. The voice cards are perfectly fine (well, at least 7 of them are, but that’s a different issue).

I followed the signals and after the two electrolytic caps C288 and C289 both Mix 1 and Mix 2 are similarly strong and sound clean.

Then however after the two resistors (R220 for Mix 1 and R228 for Mix 2) the signal is massively attenuated for Mix 1, but only slightly attenuated for Mix 2. By massively attenuated I mean if you listen to the input signal at R220 at normal volume, you barely hear the output signal.

I have no idea which one of the two is right, Mix I is getting attenuated too drastically I believe, but then again, I am having problems with Mix 2 in the end.Should that 30k resistor really attenuate the signal that much?

By the way, I have swapped out all the ICs on the mother board, one by one to no avail.

If one of you has some more ideas I will give it another try, but I believe at this point I need someone with actual electronics knowledge to look at it.

Thanks, as always!
Here's a fun one that is in a similar area that happened to me after my build.
"Now that my ddrm is up and running and I have spend a little time jammed through the presets I seem to have a bit of a problem. Osc II doesn't work correctly. Square, Saw or Noise is not there, all silent. The Sine works just fine though. It is the same for all four voice cards so perhaps some mix point somewhere."

After some advice I started probing the path in question and found this:

"As soon as I probed pin 14 on IC46 I got sound out of Osc II! Turns out the pin has no connection to the socket sleeve! Elusive as hell, will post a pic. Looks like the inner sleeve of the socket is missing or something. When I put the probe in, it shorts the socket to the pin and it's all good! "

Replacing the socket fixed the problem.
I'm guessing your issue could be similar if a pin only has a sporadic connection.

Thinking about this, I would try to figure out if it happens if Square and Saw are both off and then try to reproduce it with only Sine and then only Noise - since they have a different path and can help isolate the area.

Image

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synthcube
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Post by synthcube » Wed Mar 20, 2019 4:05 pm

Just curious-- with the Expander DIY sets coming out imminently, will Expander build notes and questions remain in this thread or will there be a separate Expander build thread?
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Post by needspeed » Wed Mar 20, 2019 4:08 pm

Unless anyone objects I do not see why not. I can update the first page and place information there.........Steve
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Post by sduck » Wed Mar 20, 2019 10:24 pm

It might be more user friendly to start a new thread for the expander - this current thread is reaching critical mass, where finding info gets hard. Mixing in a lot of new info about the expander might make it even more difficult for someone building the DDRM to find any info needed.
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