18-channel DIY Stereo Analog Vocoder

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Dr Gris
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Post by Dr Gris » Wed Aug 01, 2018 5:39 pm

Holy shit!!!
Impressive :woah: :woah: :woah:

//M

Grooverman
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Post by Grooverman » Thu Aug 02, 2018 2:54 am

glubsch wrote:In general I am thinking of selling a combo of PCBs and the front panel, probably starting out with a limited run of 12 sets (PCB + front panel) to get this going.

Does this mean You're going to make "pre-run" of 12 sets and then a bigger "production-run" or will it be more limited to the first 12 set? I would really like to get in on this but I feel that I'm not that well suited to "beta-test" or help ironing out faults…


But really nice sound in this, and it looks awesome!!! Great job!

Grooverman
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Post by Grooverman » Thu Aug 02, 2018 2:55 am

glubsch wrote:In general I am thinking of selling a combo of PCBs and the front panel, probably starting out with a limited run of 12 sets (PCB + front panel) to get this going.

Does this mean You're going to make "pre-run" of 12 sets and then a bigger "production-run" or will it be more limited to the first 12 set? I would really like to get in on this but I feel that I'm not that well suited to "beta-test" or help ironing out faults…


But really nice sound in this, and it looks awesome!!! Great job!

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audiohawk
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Post by audiohawk » Thu Aug 02, 2018 12:30 pm

Awesome!
When the time comes, count me in for one set.
Thank you for your work :hail:

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glubsch
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Post by glubsch » Thu Aug 02, 2018 12:36 pm

First off, thanks for all the kudos. All the feedback through this forum and email is very encouraging.

Grooverman, The first twelve wigglers would get a discount. After that, I'd sell the PCB+front panel combo at a regular price. Instead of calling it limited run, let me use your wording and call it "discounted pre-run". The idea is to get this off the ground quickly, and while I think there's no need to beta test the hardware, I would count on the first 12 wigglers to help work out the kinks from the documentation. For those who join the first 12, I would provide intense support as I really don't want anyone to be disappointed with this project.

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glubsch
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Front panel design

Post by glubsch » Thu Aug 02, 2018 12:57 pm

So here's the front panel, adjusted for size (width 483 mm, height 132.5 mm, depth 3 mm). It contains screw holes that fit the rack from Hifi2000 ("Slim Line 03/230 3U") and screw holes for handles from Schroff (catalog number 20860-258).

This panel and the PCBs would be part of the discounted pre-run.

Image

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HighLordFixer
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Post by HighLordFixer » Thu Aug 02, 2018 1:43 pm

looks completely fabulous!
throw some prices at use when you do more math
so we can then do some math
so the cv ins/outs functions like the bode/moog vocoder?
Image

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glubsch
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Post by glubsch » Thu Aug 02, 2018 2:28 pm

HighLordFixer
I haven't checked the CV in/outs from the Bode/Moog vocoder series.

You can get that information from Technical Details section of the brochure. In essence: the CV controls for the internal excitation sections are 1 V/oct, allowing you to control from 0...10 V (though using the associated frequency range (10 octaves) doesn't make a lot of sense in a vocoder). The CV in/outs from the patch bay work from 0...5 V. I couldn't let it go all the way to 10 V as it essentially wouldn't leave any headroom for the envelope followers (The operating voltage of the vocoder is +/-12 V). The LED peak indicators are configured to have the LEDs fully illuminate at 5 V.

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glubsch
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Post by glubsch » Sat Aug 04, 2018 7:44 am

I am in the middle of preparing a document with general information about the BOM and sourcing parts. While preparing, I shot this photo. It shows you the recessed placement of the pots in the front panel. As you can see, this helps placing the Davies knobs very close to the surface of the front panel, making it look much more professional.

Image

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Leverkusen
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Post by Leverkusen » Sat Aug 04, 2018 8:56 am

Looks great indeed! But I can't figure out how the pots are attached to the frontplate, or aren't they?

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glubsch
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Post by glubsch » Sat Aug 04, 2018 12:17 pm

Leverkusen wrote:Looks great indeed! But I can't figure out how the pots are attached to the frontplate, or aren't they?
Take another close look at the picture above, it's the nut that comes with the pot. As a regular wrench will not fit in the whole, I had someone create a custom socket with a 3D printer. I will include this custom socket for each panel. I didn't want to create a wider recess as it otherwise wouldn't be covered by the slim Davies knobs.

The socket in the picture has some stains from its frequent use. I hope it is not too hard to see what it actually looks like.

Image

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needspeed
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Post by needspeed » Sat Aug 04, 2018 12:38 pm

i am in for sure after building 7 Deckards Dreams I need a change of pace Hee hee hee...... Steve
To a never ending journey of exploring all noise that may or may not be music to someone or anyone.

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glubsch
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Post by glubsch » Sat Aug 04, 2018 1:23 pm

needspeed wrote:i am in for sure after building 7 Deckards Dreams I need a change of pace Hee hee hee...... Steve
Uh, ok... I had to look this up as I didn't know what Deckard's Dream actually is. You must have some special permissions or something as they are on preorder, right?

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tjs
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Post by tjs » Sat Aug 04, 2018 1:48 pm

It never stops... Impressive!

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needspeed
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Post by needspeed » Sat Aug 04, 2018 2:14 pm

glubsch wrote:
needspeed wrote:i am in for sure after building 7 Deckards Dreams I need a change of pace Hee hee hee...... Steve
Uh, ok... I had to look this up as I didn't know what Deckard's Dream actually is. You must have some special permissions or something as they are on preorder, right?
DDRM Kit here and also can be ordered pre-built here: DDRM Kit

No U do not need permission for new runs. The locked ones are closed runs that are yet to be completed.

They are on rev 2 now so that is in pre-order I have build all Rev 1s so far.....Steve
To a never ending journey of exploring all noise that may or may not be music to someone or anyone.

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glubsch
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Post by glubsch » Sun Aug 05, 2018 1:45 pm

Back on topic: would wigglers expect using their own power supplies? The vocoder requires +/-12 V at about 1.2 A each polarity. To give it some reserve, I'd suggest 1.5 A per polarity at a minimum. I've designed a supply that dissipates surprisingly little heat if a +/-12 V transformer is used.

I'm wondering though if it is more economic (and also safer to the end user) to use a commercially available supply, maybe an SMPS. I've had little luck finding such a power supply online. Who can give me some leads?

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Thalassa
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Post by Thalassa » Sun Aug 05, 2018 2:20 pm

And what about using an external psu and an internal DC / DC converter ?

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glubsch
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Post by glubsch » Sun Aug 05, 2018 2:38 pm

Thalassa wrote:And what about using an external psu and an internal DC / DC converter ?
Can you give me a hint what this would actually look like? A specific example?

Edited to say: I've just looked it up and I don't see how this could be an economical solution. The DC/DC converter would have to be supplied by an external power supply providing DC voltage, right? At a power rating of ~40 W, the DC/DC converter alone is about 50€. I am looking at the JCK4012D12. It appears to be a buck/boost converter as it allows 9 V as minimum input voltage.

I will keep investigating...

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Thalassa
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Post by Thalassa » Sun Aug 05, 2018 3:21 pm

It's the typical external transformer like on the laptops . The input is 110-240v and output for example 24V DC. Inside of the vocoder will be a DC /DC converter that will transform the 24Vdc in +/- 12V .

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Thalassa
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Post by Thalassa » Sun Aug 05, 2018 3:33 pm

glubsch wrote:I've just looked it up and I don't see how this could be an economical solution. The DC/DC converter would have to be supplied by an external power supply providing DC voltage, right? At a power rating of ~40 W, the DC/DC converter alone is about 50€. I am looking at the JCK4012D12. It appears to be a buck/boost converter as it allows 9 V as minimum input voltage.

I will keep investigating...
It's a safe solution because no dangerous voltages are present inside of the vocoder but as you said is not cheap.

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julian
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Post by julian » Sun Aug 05, 2018 3:47 pm

Is there a problem with having a power board that the end builder wires their toroidal to?

A project like this is hardly a beginners build, and i would have thought that any constructor would be competent to include mains voltages / earthing etc within their unit.
.



_________

For stocked euro / buchla / midibox see - http://thebeast.co.uk/?post_type=product

For custom cnc engraved panels see - http://thebeast.co.uk/?page_id=21

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Thalassa
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Post by Thalassa » Sun Aug 05, 2018 3:53 pm

BTW how your prototype version is powered? Can't you use it in the final design?. As Julian said this is not a begginners project :)

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paterursus
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Post by paterursus » Sun Aug 05, 2018 4:03 pm

Just one person's opinion here - if there is room inside the case I would prefer a linear PSU inside with an IEC connector outside. It's tidier and more professional-looking. If you found standard parts you could create a shield for the dangerous mains side.
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glubsch
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Post by glubsch » Sun Aug 05, 2018 4:07 pm

Thalassa wrote:
glubsch wrote:I've just looked it up and I don't see how this could be an economical solution. The DC/DC converter would have to be supplied by an external power supply providing DC voltage, right? At a power rating of ~40 W, the DC/DC converter alone is about 50€. I am looking at the JCK4012D12. It appears to be a buck/boost converter as it allows 9 V as minimum input voltage.

I will keep investigating...
It's a safe solution because no dangerous voltages are present inside of the vocoder but as you said is not cheap.
OK, you just gave me an important hint. I didn't realize that the DC/DC converters don't need dual input supply for delivering dual output. According to the datasheet for the JCK4012D12, A 12 VDC supply providing up to 3.7 A will suffice. A simple 12 VDC switching table top supply delivering 5 A is about 20...30€. The required 68 µH choke is only a couple of Euros.

I'm not sure how to interpret the maximum capacitive load of the JCK4012D12 (+/-1200 µF). Need to investigate further...

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glubsch
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Post by glubsch » Sun Aug 05, 2018 4:21 pm

OK, I see more posts have come up in the meantime while I was preparing my previous post. To answer them all: yes, my current power supply concept uses a toroidal transformer inside the rack, followed by a linear PSU based on the MIC29300-12WT and Schottky diodes (combined with some beefy electrolytic caps). The toroidal is just 2x 12 V, therefore the power dissipation is quite acceptable. Hardly any ripple at the PSU output (I had to put major effort in a clean PCB design to ensure this). The caveat: There's mains power inside the rack.

BTW, here's a picture of the power board:

Image

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