208p build thread (papz's PCBs)
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- papz
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208p build thread (papz's PCBs)
FAQ
Buildnotes and calibration
(Build notes for the early "promotional offer" revision)
Parts layout
Schematics
Mouser cart 1
Mouser cart 2
I didn't check the carts content and assume no liability for their accuracy
Happy building !
Buildnotes and calibration
(Build notes for the early "promotional offer" revision)
Parts layout
Schematics
Mouser cart 1
Mouser cart 2
I didn't check the carts content and assume no liability for their accuracy
Happy building !
Last edited by papz on Thu Jun 25, 2020 5:16 pm, edited 15 times in total.
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- the bad producer
- Super Deluxe Wiggler
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4U panels for sale/4U wiring diagrams/4U stuff here: http://www.loudestwarning.co.uk/
And here, http://loudestwarning.tumblr.com/
https://www.instagram.com/loudestwarning/
And here, http://loudestwarning.tumblr.com/
https://www.instagram.com/loudestwarning/
- papz
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I updated the cards pics with components layout and values and the build notes.
The C5 47µF tantalum cap mentioned in the BOM works fine in the CO instead of the 56µF.
R45 100k instead of 20k eases tracking calibration.
The C5 47µF tantalum cap mentioned in the BOM works fine in the CO instead of the 56µF.
R45 100k instead of 20k eases tracking calibration.
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- papz
- Super Deluxe Wiggler
- Posts: 3537
- Joined: Sat May 18, 2013 6:52 pm
- Location: in a suitcase
- Contact:
Me too for sure ! 

Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- beautyofdecay_
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- papz
- Super Deluxe Wiggler
- Posts: 3537
- Joined: Sat May 18, 2013 6:52 pm
- Location: in a suitcase
- Contact:

Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- papz
- Super Deluxe Wiggler
- Posts: 3537
- Joined: Sat May 18, 2013 6:52 pm
- Location: in a suitcase
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Some extra infos added in the build notes.
It's better to match the vactrols on boards 10 and 11, or use dual VTL5C3/2.
Vactrols VT4 and VT2 on board 5 need to be selected on test for proper AM performance.
On board 7, R3 should be selected on test, a value between 3k8 and 12k, depending on the vactrol, to set the desired timbre amplitude. I find 4-5 folding is good, as shown on http://modularsynthesis.com/buchla/208/buchla_208.htm but others prefer more foldings. It's up to the builder to select what best suits his needs.
On board 8 the 2N4399 needs selection on test for proper sine waveshape.
I think this depends not only on the part itself but on the other parts in the circuit as well, therefore I use to select parts on test directly in each circuit.
It's better to match the vactrols on boards 10 and 11, or use dual VTL5C3/2.
Vactrols VT4 and VT2 on board 5 need to be selected on test for proper AM performance.
On board 7, R3 should be selected on test, a value between 3k8 and 12k, depending on the vactrol, to set the desired timbre amplitude. I find 4-5 folding is good, as shown on http://modularsynthesis.com/buchla/208/buchla_208.htm but others prefer more foldings. It's up to the builder to select what best suits his needs.
On board 8 the 2N4399 needs selection on test for proper sine waveshape.
I think this depends not only on the part itself but on the other parts in the circuit as well, therefore I use to select parts on test directly in each circuit.
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- papz
- Super Deluxe Wiggler
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- Joined: Sat May 18, 2013 6:52 pm
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Thanks for the feedback 

Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- papz
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- Joined: Sat May 18, 2013 6:52 pm
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25V is ok for the electrolytics, these are between each +15V/-15V/+10V rails and ground. But higher voltage is ok, I generally use 50V since I mostly stock these, are the same size and price as 25V and can do more. Also, the higher the voltage rating, the longer the life expectancy.
I'd rather use 1/4W resistors.
The DIP10 emplacements are to connect the pA726 to the boards, vertical one to 6 and horizontal one to 7.
I'm not sure the holes are large enough for headers.
I simply use thick components legs, there are much more than needed when building a 208.
"1" shows the µA726's pin 1, "tab" the µA726's tab/pin 10.
The trimpot should be on the same side as the other trimpots, this way you can't be wrong.
More details and pics on http://www.portabellabz.be/pa726.html
I'd rather use 1/4W resistors.
The DIP10 emplacements are to connect the pA726 to the boards, vertical one to 6 and horizontal one to 7.
I'm not sure the holes are large enough for headers.
I simply use thick components legs, there are much more than needed when building a 208.

"1" shows the µA726's pin 1, "tab" the µA726's tab/pin 10.
The trimpot should be on the same side as the other trimpots, this way you can't be wrong.
More details and pics on http://www.portabellabz.be/pa726.html
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- beautyofdecay_
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That's a good idea.papz wrote:Some extra infos added in the build notes.
It's better to match the vactrols on boards 10 and 11, or use dual VTL5C3/2.
I think a VTL5C3/2 should work like this? The vertical blue line is a wire link.

The wires of the original VTL5C3/2 are long enough to connect the vactrol this way. I don't know about the current clones however...
- papz
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Or this way.
Legs can be extended with wire if needed.

Legs can be extended with wire if needed.

- Attachments
-
- 101_0469.JPG (251.17 KiB) Viewed 1157 times
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
-
- Learning to Wiggle
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- Joined: Tue Aug 23, 2016 12:46 am
Hi everyone. I am new at this, so not sure how good it is.
I compiled a Mouser project based on the BOM lists from PDFs. Mouser project has all the components that can be found based on those BOMs, so parts that are rare and cannot be found on mouser, including sliders, pots and hardware parts are not included.
I also included everything needed for pA726 except for CA3046 and two pin header.
In the attachment are all Excel files generated from PDFs, including a compiled mouser cart, where all parts that are not in stock are replaced with other part number. Compiled Excel doesn't include parts needed for pA726.
I hope this will help.
Mouser project 208
I compiled a Mouser project based on the BOM lists from PDFs. Mouser project has all the components that can be found based on those BOMs, so parts that are rare and cannot be found on mouser, including sliders, pots and hardware parts are not included.
I also included everything needed for pA726 except for CA3046 and two pin header.
In the attachment are all Excel files generated from PDFs, including a compiled mouser cart, where all parts that are not in stock are replaced with other part number. Compiled Excel doesn't include parts needed for pA726.
I hope this will help.
Mouser project 208
- Attachments
-
- Buchla 208 boms.rar
- (102.44 KiB) Downloaded 85 times
- beautyofdecay_
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- Location: Netherlands
I think there is a mistake in your BOM (I made the same mistake...
)
You should order CD4016, not CD4066!
The original BOMs from Roman specifies the CD4066. Check the PCB layout pictures from papz (or the original Buchla schematics). There only 4016s are used.
EDIT: checked the datasheets and the 4066 can be used also as it is an updated version of the 4016... Sorry for the confusion!

You should order CD4016, not CD4066!
The original BOMs from Roman specifies the CD4066. Check the PCB layout pictures from papz (or the original Buchla schematics). There only 4016s are used.
EDIT: checked the datasheets and the 4066 can be used also as it is an updated version of the 4016... Sorry for the confusion!
-
- Learning to Wiggle
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- Joined: Tue Aug 23, 2016 12:46 am
- papz
- Super Deluxe Wiggler
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Thank you sanemalkavian
Some 4016 may cause problems indeed, which can be avoided using 4066 instead. I now use 4066 in all my 208 builds.
In case some wonder whether this affects the sound, the answer is no, these ICs are used to voltage control switches.

Some 4016 may cause problems indeed, which can be avoided using 4066 instead. I now use 4066 in all my 208 builds.
In case some wonder whether this affects the sound, the answer is no, these ICs are used to voltage control switches.
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- papz
- Super Deluxe Wiggler
- Posts: 3537
- Joined: Sat May 18, 2013 6:52 pm
- Location: in a suitcase
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Some builders ask me about this on the promo PCBs card 8.

The trace touched the eyelet and was rectified at last minute, but the solder mask wasn't rectified.
So no worries, it is ok and can be used as is.

The trace touched the eyelet and was rectified at last minute, but the solder mask wasn't rectified.
So no worries, it is ok and can be used as is.
- Attachments
-
- card8.jpg (50.39 KiB) Viewed 1159 times
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
- beautyofdecay_
- no maps for this area
- Posts: 336
- Joined: Sun Feb 27, 2011 2:26 pm
- Location: Netherlands
- papz
- Super Deluxe Wiggler
- Posts: 3537
- Joined: Sat May 18, 2013 6:52 pm
- Location: in a suitcase
- Contact:

[video][/video]
Finest EMS gear service and Music Easel/208 goodies
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
I'm not a synths dealer and I'm not aware of an inexpensive Synthi secret market, please don't ask me if I know one for sale.
I don't offer support of any kind to people attempting to build clones of EMS equipment.
Panel files for 208
Since I can't seem to find anyone offering panels for the 208 right now, I was wondering if anyone has drawing files (especially drilling centres) for the 208.
Formats can be .svg .ai .dxf ... anything editable.
I'm not looking to make a clone... I actually want to customize the look of the panel for myself. But of course the locations of the hardware must remain the same.
anybody???
Formats can be .svg .ai .dxf ... anything editable.
I'm not looking to make a clone... I actually want to customize the look of the panel for myself. But of course the locations of the hardware must remain the same.
anybody???
https://electricmusicstore.com should have both panels and a drill sheet