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DIY - Elektor Vocoder - Project Description
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3 ... 14, 15, 16  Next [all]
Author DIY - Elektor Vocoder - Project Description
Fitchie
Project update:

24/12/2017 - PCB design started (basic version)
03/01/2018 - First batch PCB's ordered (basic version)
16/01/2018 - Front panel design started
25/01/2018 - First batch PCB's received (basic version)
28/01/2018 - 3D printed parts available
30/01/2018 - PCB design started (extended version)
10/02/2018 - In/out module prototype ready
11/02/2018 - Power supply 240 VAC prototype ready
31/03/2018 - All PCB's available for the basic version
01/04/2018 - Backplane prototype ready
12/05/2018 - Filter unit prototypes ready
14/05/2018 - Last batch PCB's ordered (extended version)
30/05/2018 - Official interest list available
03/06/2018 - All PCB's available for the extended version
08/06/2018 - Final front panel design ready
10/06/2018 - Sibilance expansion prototype boards ready
04/07/2018 - Frontpanel prototype ordered
05/07/2018 - Kit-testing by LED-man
14/07/2018 - Frontpanel delivered
17/07/2018 - Redesigned power supply 110/240 VAC
31/07/2018 - First assembly ongoing
18/08/2018 - Filters tested
25/08/2018 - First demo sound (basic version)
01/09/2018 - Irresistible price drop, orders accepted
09/09/2018 - Final assembly and cabling
17/09/2018 - New demo posted
20/09/2018 - Fully assembled and working device
22/09/2018 - Dedicated website launched www.vocoder.eu/index.html
23/09/2018 - Consolidated BOM available www.vocoder.eu/bom.html
30/09/2018 - Interest list closed
03/10/2018 - Batch production 3D printed parts
04/10/2018 - Order forms sent out
12/10/2018 - Production run frontpanels received
25/10/2018 - Production run PCB's received
27/10/2018 - Merging kits
31/10/2018 - First shipments to Europe customers
01/11/2018 - Build thread created
07/11/2018 - Final BOM available
08/11/2018 - First shipments to US & Canada customers

Prototype:



Assembled vocoder:



Sound demos:

[s]https://soundcloud.com/boo-gie-879149310/vocoder-demo1[/s]
[s]https://soundcloud.com/user-590053363/vocoder-demo-1[/s]

Project description:

Hello everyone !

I'm a synth & electronics passionate fan and live in Antwerp, Belgium. In the mid-80s, really young and inexperienced, I decided to build the Elektor 10 channel vocoder.

In those days, board designs were published in magazines, afterwards mirrored and copied on transparent foils, heat transferred to hand drilled boards. And last but not least, ferric chloride dissolved in water was used to etch the PCB's. As you know the original Vocoder is built on a total of 14 PCB's, it was a complex and nasty job to completed all boards.

There also was no internet, no "one day order and delivery" from Mouser or Farnell, so getting all your components was quite complex and labor intensive. But I was convinced to build my own Vocoder and putted al my pocket money in. Months later with the unaffordable help of my best friend, I succeeded to finish the heavily under-estimated build.

Here is a picture from the 35 years old device, still operational, but dusty and abandoned.



For quite a long time, I would like to rebuild this Vocoder, but never had the courage to start this project. The initial idea was to make an exact replica as described in the Dutch Elektor magazine (January & February 1980), but with the unworthy and noxious PCB process in mind, I decided to redraw all PCB's to outsource the production of them.

All the design are exact replica of the original electronic schemes, except the initial published errors and the new PCB's are using old trusted through hole components. As improvement the original 2 parts backplane will be cropped and merged to fit on one large PCB and the power supply will be redesigned to plug in the backplane.

The Vocoder will be build up based on those 5 modules:

- Backplane
- Power supply
- In/out module
- High pass filter
- Low pass filter

Also 8 bandfilters are needed:

- 265 Hz
- 390 Hz
- 550 Hz
- 800 Hz
- 1200 Hz
- 1770 Hz
- 2650 Hz
- 3900 Hz

2 years later Elektor did publish a sibilance expansion, based one those PCB's:

- Noise generator
- Detecting interface
- Switching module

The last month I did draft the global approach of this project and already designed the new backplane and power supply. And at the moment I'm finishing the layout of the PCB's and hope to order a first (test) batch beginning next year.

For clarification one can see below the block diagram of the entire vocoder:



As you might except and if you are interested, this will be a DIY project and I will offer PCB's, BOM's and a 19" frontpanel so that everyone can build his own Vocoder. I'm really enthusiastic to expose this project to all of you, and especially on Muff Wiggler where I was till now only a lurker.

I'm glad to hear from you!
Jarno
Nice project!

With respect to components, I wouldn't be too afraid to use SMT IC's as they save a lot of room, and were there any "weird" components in this? IMHO, a lot of the Elektor projects sometimes had overly complex circuits or components that were hard to get, even when in production.

Do you have some pictures from your boards?
Fitchie
Hi Jarno,


We all known Elektor for their designs based on rare components they got from manufacturers to build a project around, so I did investigate the original components list as well and can inform you there are no "hard to get" components used.

Short overview of the used semiconductors:

- BC547x (20 pcs)
- TL084 (20 pcs)
- 741 (10 pcs)
- CA3080 (10 pcs)
- TDA1034 (5 pcs)
- LM308 (1 pc)
- 78xx (2 pcs)
- 79xx (2 pcs)

Below you'll find some pictures of the original boards I built in the mid-80s. Left side is the in/out module, right side is one of the filter units:

Haralds:Werk
Great project! Keep going. For inspiration or adaption you might look here: http://www.haraldswerk.de/PP_Vocoder/PP_Vocoder.html
I considered building a Elektor Vocoder as well but then decided to go another road.
Jarno
TDA1034 = NE5534
And replace the 3080's with LM13700? CA3080 is expensive and often faked.

Any reason for specifying so many different opamps? (741, TDA1034, LM308, TL084) Maybe just settle on one throughout?
goodrevdoc
I've wanted to build one of these forever, but never had the gumption to make boards based on the scans on the net. Super interested and thanks for the legwork.
-justin
stringsthings
This project looks very interesting!

I do have a question about some of the parts:
Fitchie wrote:


Short overview of the used semiconductors:

- BC547x (20 pcs)
- TL084 (20 pcs)
- 741 (10 pcs)
- CA3080 (10 pcs)
- TDA1034 (5 pcs)
- LM308 (1 pc)
- 78xx (2 pcs)
- 79xx (2 pcs)


As mentioned by Jarno, the CA3080 is expensive/obsolete, and could be replaced by the LM13700.

And the TDA1034 was replaced by the NE5534 it seems.

Although the 741 is still widely available, there are lots of equivalent op-amps that are superior.
yan6
Looking good and interested
minime123
we may be interested in one for our studio vocoder arsenal.
mini
Fitchie
All,


Thanks for your great feedback and suggestions for replacement components. This is really appreciated !
Meanwhile the redesigned backplane is ready and triple checked. Next one will be the power supply.

Component side backplane (380 mm x 72 mm):



Solder side backplane:

minime123
thanks for labelling the pcb. i just stuffed a buchla 259r and it was a major pain in the ass without proper labelling.
mini
Fitchie
To become a bit nostalgic, I added the original Elektor PCB's.
This is 35 years of history !

Fitchie
PWM
stringsthings wrote:
Although the 741 is still widely available, there are lots of equivalent op-amps that are superior.



Superior is not the correct word, imo. There are opamps that have a faster slew rate and a better n/s ratio but that doesn't make them superior per se.
They're different and can be better in different applications. I like 741, 1458 and 4558s in my modules and or sound processing equipment. Take Jurgen Haible's Kroutrock Phaser for instance. This thing sounds amezing and is packed with 1458s!
sanders
I hope I'm not too far off topic here-- but I've often wondered, what are the difficulties in achieving the level of speech articulation that one finds with vintage commercial vocoders like EMS, Moog, and even the Roland and Korg?

Most of the audio I've heard from the current crop of diy projects seem to be on par with the Paia Vocoder. The effect is decent for sure, but speech comes across vague, and not well defined.

Is it unrealistic to expect the level of articulated speech one hears on Kraftwerk or Giorgio Moroder records from a DIY project (which probably makes some design concessions in favor of ease of assembly)?
KSS
sanders wrote:
I hope I'm not too far off topic here-- but I've often wondered, what are the difficulties in achieving the level of speech articulation that one finds with vintage commercial vocoders like EMS, Moog, and even the Roland and Korg?

A very good question. Have a look at Harald's vocoder link to see the extras required for the results you're looking for.

Quote:
Most of the audio I've heard from the current crop of diy projects seem to be on par with the Paia Vocoder. The effect is decent for sure, but speech comes across vague, and not well defined.

Not meaning to throw water on the fire in the OP's efforts, but this one is likely similar to the PAIA. PAIA is much improved with Scott's clarifying mod.

Quote:
Is it unrealistic to expect the level of articulated speech one hears on Kraftwerk or Giorgio Moroder records from a DIY project (which probably makes some design concessions in favor of ease of assembly)?

In a word, Yes. Again, see all the extras beyond input, output and filters at Haralds excellent site. Again, not wanting to diss this project at all. There is room for all types of sounds in what we do.

@ Fitchie: Great project! Those buss connectors remind me of the expensive unobtainium connectors which seem to be a mainstay of 70's UK synth magazine projects. Were I in your shoes, they would be the very first thing to go. Exchanged for either typical dual row 2.54 headers or maybe a 156 molex like the Buchla easel.
Haralds:Werk
sanders wrote:
I hope I'm not too far off topic here-- but I've often wondered, what are the difficulties in achieving the level of speech articulation that one finds with vintage commercial vocoders like EMS, Moog, and even the Roland and Korg?

Most of the audio I've heard from the current crop of diy projects seem to be on par with the Paia Vocoder. The effect is decent for sure, but speech comes across vague, and not well defined.

Is it unrealistic to expect the level of articulated speech one hears on Kraftwerk or Giorgio Moroder records from a DIY project (which probably makes some design concessions in favor of ease of assembly)?


No not necessarily. To operate a analog vocoder correctly it needs a lot of practice and experimenting. You need to know what exciter to use and how to articulate your words and how to set the tone controls of the speech input. And how to set the band controls and the limiter and .... In short it need s experience and more time experimenting than building it.
Most of the diy vocoders are on the qualitative low side though. Only a few filter bands, crappy filters, wrongly spaced, badly build. Go for at least 20 filter banks with 48dB filters.
Haralds:Werk
The connectors are industrial standard. DIN41617
Search for "Federlesite 21L" at www.reichelt.de

But if memory serves the capacitor values used in the filters are uncommon today. You might need to recalculate them. And have a look at Dirk Lindhofs work. He already build one and sells them. http://synthlab.de/elektor-vocoder.html
Fitchie
KSS wrote:
Those buss connectors remind me of the expensive unobtainium connectors which seem to be a mainstay of 70's UK synth magazine projects. Were I in your shoes, they would be the very first thing to go. Exchanged for either typical dual row 2.54 headers or maybe a 156 molex like the Buchla easel.

Conec is still producing those nostalgic connectors:

- 21 pin male : 101E10099X
- 21 pin female : 102E10079X





Take care not to order the L (solder lugs) version, this one will not fit in the backplane.
For full datasheets please see below attachments.
efexor
Haralds:Werk wrote:
Great project! Keep going. For inspiration or adaption you might look here: http://www.haraldswerk.de/PP_Vocoder/PP_Vocoder.html
I considered building a Elektor Vocoder as well but then decided to go another road.


Your Vocoder project is awesome.
Wish i had the skills to built it one day.

I own 5 Elektor formant Systems,but they all need work,but this is in progress.

Had the chance to buy that Elektor Vocoder a few times but missed it very frustrating
efexor
@ Fitchie
So cool you still own this after 35 years.
Fitchie
As promised, here is the new designed power supply. In contrast to the original layout, all importants parts are on the main PCB:

- transformer
- fuse
- 7805 & 7815
- 7905 & 7915

As a result the previous published backplane is lean & mean and does not contain active components anymore.

Component side (172 mm x 72 mm):



Solder side:

Fitchie
The original Elektor print is shown below for comparison:

KSS
Thank you for the education on those connectors. Very nice!

You may want to re-configure the power supply board by roatating the 4 Vregs as a group 90 degrees. Heat rises. Right now the top Vreg gets all the heat rising from those below. Adding to the problem, heatsinks are typically aligned to work against the orientation you have here.

The synthlab.de website has a good picture of the right way to do a eurocard power supply in the PDF for Dirk's 808 and 909 Drum clones.
The capacitors will likely need rotating also to make room. The graphics area changes, but I'd say long lasting and readily convectively cooled power is more important. I imagine the heatsinks on your original are rotated this way too. It's worth the effort to make it right.
KSS
I see now the original is the same orientation but only see two Vregs? At a minimum you could add some decent PCB-based heatsinking traces and pours as is seen on many power PCBs using SMD. You have the clean open areas available to do this. Done well, these PCB trace and via-based cooling techniques can make a big difference.
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