18-channel DIY Stereo Analog Vocoder

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Modulart_JP
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Post by Modulart_JP » Sun Sep 09, 2018 3:36 am

T18 shaft pots that should do the job are available from Mouser.
100K lin single gang:
https://www.mouser.jp/ProductDetail/652 ... -2015KB104

100K log single gang:
https://www.mouser.jp/ProductDetail/652 ... -2015KA104

100K log dual gang:
https://www.mouser.jp/ProductDetail/652-PTD9021015KA104

And it seems they are cheaper.

I'm really interested in this project.
However, I think you should stick to provide only PCBs.
Such a panel made by Schaeffer will be very expensive and many people might prefer to go for a local manufacturer.
Also, the choice of an enclosure not being widely available is not the best, IMO.
Again, with people making their own panel, it is possible to source a suitable enclosure locally at a better price.
I can have a 3U rack enclosure from my local RS for about 35 EUR.
If I buy the panel from you and it is not compatible, I'll have to order the HIFI2000 rack from the few places where it is available for sale and it will end up costing around 100 EUR...ouch.

My 2 Yens... 8-)

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Post by glubsch » Sun Sep 09, 2018 11:33 am

Hi Modulart_JP, your input is worth more than 2¥. the pots you are suggesting seem to fit but do you know of knobs that fit as well and are not wider at the base than the Davies knobs (13 mm)? If there is a viable alternative, I will certainly look into it in more detail. In fact, if there were knobs small enough that covered the whole pot shaft and had a wall thin enough to cover the nuts, we'd have an alternative solution to the panel cavities/recesses.

When I started out this project, I looked for a solution that works for me and that's what I am promoting because I need to start out simple. Please stay tuned for more details.

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Post by glubsch » Sun Sep 09, 2018 11:56 am

tobb the only one fitting at the base at Thonk's are called "small tall". But they are only offered as D type. The one found at Farnell is simply to wide at the base.

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Post by tobb » Sun Sep 09, 2018 12:04 pm

yes,you will not find any knob xtra small with a skirt that cover the nuts

I searched years ago already for a solution when i did a 5U modular with very small panels and knobs...

So if you want to cover the nut,change the design so you can use a larger knob or you will have to stick with the special CNC holes.

Or use a double pot bracket/backplate,but then you will have to move from alu front panel to steel panel because it has to be a very thin front so the knob shafts still can stick far enough to be able to fix the knobs on it.

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Post by Oldstench » Sun Sep 09, 2018 12:48 pm

Stunning work glubsch.

I'm not much more than an advanced beginner in DIY, so this is certainly outside my skillset, but I will certainly be watching this thread with great interest.

Fantastic stuff.
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Post by Jarno » Sun Sep 09, 2018 2:19 pm

tobb wrote: Or use a double pot bracket/backplate,but then you will have to move from alu front panel to steel panel because it has to be a very thin front so the knob shafts still can stick far enough to be able to fix the knobs on it.
I was going to suggest a "false front" for the frontpanel. Pots are fastened on the enclosure, and the frontpanel (with adequately sized holes) is mounted on the enclosure. This is how it is done on a lot of equipment. But usually those use bigger knobs, so nuts will always be covered. Are the higher knobs really that important? It is a lot of machining, and if you make the pockets big enough for the nut (and the tool!) you'll see them unless using larger knobs (or skirted ones).

Also, if the enclosure is stiff enough, you can get away with using a dibond front, which is less expensive (not sure about esthetics, although I do think you can print in photo quality on dibond).

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Post by tobb » Sun Sep 09, 2018 3:51 pm

Jarno wrote:
tobb wrote: Or use a double pot bracket/backplate,but then you will have to move from alu front panel to steel panel because it has to be a very thin front so the knob shafts still can stick far enough to be able to fix the knobs on it.
I was going to suggest a "false front" for the frontpanel. Pots are fastened on the enclosure, and the frontpanel (with adequately sized holes) is mounted on the enclosure. This is how it is done on a lot of equipment.
Its a bad solution and the wrong way for diy

Because then you have to buy the front/enclosure and send them to the metal shop for making the holes..usually its a profiled panel so is extra machine setup costs.

Also the fake front will carry all the weight of the rack,and this can be a bad thing depending how the fake front is attached to the frame..

Best is to find like mentioned before an enclosure where a whole non profiled panel can be fit on it,that way you can simple manufacture a replacement metal (steel) front and a blank backpanel that will hold the pcb assemblies ,the only difficulty will be finding the right size spacers as tall as the nut + washer) and determination of placements of the screwholes on the front that will hold the backplate assembly.

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Post by tobb » Sun Sep 09, 2018 4:56 pm

found, 19'' rack washers!!

it works great!

These looks the same those i have (base need to be flat otherwise washer will split (and also net deep enough anyway))

Could also be used the other way,over the nut ,no tool needed then but it will be loose rotating,not that pro..

https://www.bluearan.co.uk/index.php?id=ADH5620

or these,better imo:

https://www.barenco.co.uk/m6-cup-washer ... lon-805006

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[/img]

looks great with Rogans to!

Image


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Post by paterursus » Sun Sep 09, 2018 6:34 pm

They look good with the black knobs, not so much so with the others. It would be great if they came in other colors.
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Post by glubsch » Mon Sep 10, 2018 12:05 pm

Tobb, thanks for the idea to use these rack washers. Bear in mind though, they'll take up a lot of space. At least enough to cover the scales. The spacing from channel to channel is 17 mm.

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Post by zephyrin » Tue Sep 11, 2018 4:20 am

Hello

Do you have the 12 first builders ? IF not i could be interrested, i have build several Vocoder (Elektor, L1, MFOS, Okita, and JH )

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Post by glubsch » Tue Sep 11, 2018 11:41 am

zephyrin wrote:Hello

Do you have the 12 first builders ? IF not i could be interrested, i have build several Vocoder (Elektor, L1, MFOS, Okita, and JH )
Thanks for your interest. I have more than 12 wigglers showing strong interest but I haven't announced pricing yet. A few things need to get sorted before I can make the announcement. So keep your eyes peeled for more details on this thread.

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Post by glubsch » Tue Sep 18, 2018 1:49 pm

Progress has been a bit slow lately but there's been progress nonetheless.

I've designed a new power supply to give wigglers an alternative and avoid running mains power through the enclosure. It's a solution based on a DC/DC converter using an external tabletop transformer, such as the GST60A12-P1J. This one's quite affordable and runs on all the various household voltages found across the world.

I'll soon update the BOM accordingly and separate out the current power supply that uses the traditional LDO-based solution.

Frankly, the DC/DC converter solution, albeit a bit more expensive, has become my preference because the vocoder output produces less noise. I don't have an audio analyzer so I can't quantify it but the difference is definitely discernible.

Here's the front and the back side. The DC/DC module is actually mounted on the back side of the PCB so that it can later be mounted onto the back panel for additional cooling. That's what the four 3 mm screw holes are meant for close to the module.

Image
Image
Last edited by glubsch on Tue Sep 18, 2018 1:55 pm, edited 2 times in total.

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Post by glubsch » Tue Sep 18, 2018 1:53 pm

Apart from the new power supply, I've made also progress on the assembly guide. I think that one's about 30% done. Since I haven't yet received my package with a handful of LM3916 from China, I've ordered enough from the UK for the first 12 wigglers who are going to sign up for the discounted PCB run. I hope to receive them next week.

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Post by glubsch » Mon Sep 24, 2018 12:58 pm

UPDATE:

Today I've received 36x LM3916, so the VU display driver ICs for the first 12 builders are secured. I've tested three of them and they are working well. :nana:

Based on all the feedback I've received, I'm now preparing some bundling options:
  • First off, there will front panel options:
    • recessed
    • non-recessed
  • There will be the option to either get the power supply PCB for the "traditional" LDO-based supply which will require you to run mains through the enclosure or use the solution based on the DC/DC converter as previously posted.
  • The bundle will also include:
    • The enclosure
    • An assembly template (more about that once I have a photo)
    • A 3D printed socket (only required for the recessed panel option)
    • The potentiometers
    • The 3.5 mm jacks (CL13845G or CL1384, depending on availability)
    • The front panel switches (H8619VBAAA, H8620VBAAA, H8601VBAA)
    • Coax cable (Lapp 2170002, required for the shielded board interconnects)
    • Connecting material (EHR-2, EHR-3, S2B-EH(LF)(SN), S3B-EH(LF)(SN), and SEH-001T-P0.6)
    • IC sockets
    • Tempcos
    • LM3916
    • Fuse holder (HTC-100M), incl. 8 A slow blow fuse (only needed for the DC/DC-converter based solution)
Pricing will finally be announced soon after I hold the panels in my hands.

With the bundling above, you essentially should be able to procure all the remaining material from Mouser or other distributors. I am not planning to add the Davies knobs as I think everyone has their own color preferences.

The assembly guide is now probably about 40% done.

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Post by tobb » Mon Sep 24, 2018 4:33 pm

Nice! :tu:

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Post by paterursus » Mon Sep 24, 2018 5:11 pm

Will there be other bundling options? I already have IC sockets and tempcos, and I just purchased some reliable LM3916 just for this project.
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Post by glubsch » Mon Sep 24, 2018 5:17 pm

paterursus wrote:Will there be other bundling options? I already have IC sockets and tempcos, and I just purchased some reliable LM3916 just for this project.
Yeah, I think I can do that. I don’t mind having some LM3916 left over. I can tailor the need on the sockets and the tempcos.

BTW, how do you define „reliable“? I got my LM3916 from the UK.

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Post by paterursus » Mon Sep 24, 2018 6:21 pm

I ordered mine from Quest components in the US. They specialize in obsolete parts, and I've never had a faulty component from them.
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Post by glubsch » Tue Sep 25, 2018 11:50 am

OK, thanks for that info.

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Preliminary Bundle Pricing

Post by glubsch » Fri Sep 28, 2018 12:57 pm

A Bundle Request Form is now available. Once I have the final panel pricing, I'll update the content.

What you see in there is already a very good price indicator for the discounted run.

Select the options you need for your vocoder and the total price will adjust accordingly.

This weekend I will update the assembly guide with a number of photos and oscilloscope pictures to illustrate expected results during calibration. I hope I can give you a sneak preview Sunday night.

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Assembly Guide Sneak Preview

Post by glubsch » Sun Sep 30, 2018 2:34 pm

I've made quite some progress over the weekend with the assembly guide. A number of Sections are still missing but I wanted to give you a chance to take a sneak preview so that you get an idea about the scope of this project. I suggest you take a look at the Sections about the "Vocoder Build Sequence", the "Cable Assembly", and the build instructions "18 Channel Filter Board Assembly". The latter should give you a pretty good idea how all the other board assembly instructions are going to look like.

Assembly Guide (sneak peek).
Last edited by glubsch on Sun Oct 07, 2018 12:39 pm, edited 2 times in total.

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Feature Comparison Chart Analog Vocoders

Post by glubsch » Sun Sep 30, 2018 2:57 pm

Here are some of the features of the VoIS compared to other DIY and commercial vocoders. No guarantees that there aren't any errors so please let me know if you feel something needs to be corrected.

Image
Last edited by glubsch on Mon Oct 01, 2018 12:51 pm, edited 2 times in total.

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Post by samplebias2 » Sun Sep 30, 2018 5:22 pm

This looks and sounds fantastic! I'm going to look around town and see if I find someone qualified to build this for me, I took electronics in high school 20+ years ago, this is way out of my league. Since only a few EMS 2000's change hands world wide each year, this may be my only option.

I did build the PAIA 8 band vocoder kit with my teacher back then, but it never sounded close to what I wanted (SVC-350) finally got one of those.

Any way to ball-park estimate the total man hours in build time?

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