EMS Synthi- Keyboard Alternatives

Discussing some incredible modules that don't quite fit into the other forum categories.

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nick_s666
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EMS Synthi- Keyboard Alternatives

Post by nick_s666 » Sun Aug 11, 2019 5:05 pm

Just received my Synthi A from Robin after the traditional loooong wait- Deep Joy, and much 'You Sunk My Battleship!' patching is afoot.

Obviously I'd love a DK1/2 or a KS, but since I'll be living on baked beans for the next year or two to pay for this fella that ain't happening..

So- any Top Tips on an affordable keyboard [and/or sequencer] that will cope with the EMS eccentricity?

Added info: I don't have any Eurorack gear, and would prefer keys to a pressure pad/membrane controller.
Also, something without a 7 year waiting list would be grand.

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Post by papz » Sun Aug 11, 2019 6:11 pm

Any CV-gate keyboard, sequencer or midi to CV-gate converter works with a cable like this https://www.kentonuk.com/products/items/leads/ems.shtml
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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.

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Post by nick_s666 » Sun Aug 11, 2019 7:36 pm

Thanks Papz [I have your excellent S+H module fitted to the Synthi BTW]

I thought the Synthis were 0.3 V/Octave, so problematic with 'modern' 1V/octave business?

papz wrote:Any CV-gate keyboard, sequencer or midi to CV-gate converter works with a cable like this https://www.kentonuk.com/products/items/leads/ems.shtml

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aethyr
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Post by aethyr » Sun Aug 11, 2019 8:41 pm

elektron analog 4 mkII should do it. not only would you get CV gate sequencing but also a 4 voice synth.

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Post by Portabella » Mon Aug 12, 2019 3:31 am

Arturia Keystep

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Post by papz » Mon Aug 12, 2019 9:07 am

The incoming CV is scaled with the input level knob.
Even the CV coming from an EMS keyboard needs scaling.

Thanks for the kind words about the S&H, looks like it's becoming a standard feature of the new Cornwall units :tu:
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I don't offer support of any kind to people attempting to build clones of EMS equipment.

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Post by chriscarter » Sat Aug 17, 2019 8:25 am

yes another vote for the Arturia Keystep

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Post by nick_s666 » Sat Aug 17, 2019 10:30 am

Lovely job- thanks all!

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Post by ersatzplanet » Sat Aug 17, 2019 12:46 pm

This is the only instance where input scaling is available on a Synthi and you are i'm sure learning. I used to own a pair of AKS and a VCS3 with a Crickelwood keyboard and the scaling for those was on the keyboards themselves. Get ready to rescale every time you add another pin on the CV path to the VCOs. With the standard Keyboards, I sometimes reached a point where it could no longer be scalable. Hopefully with a 1v/oct keyboard as a starting point, through the input jacks (which have gain IIRC) this will not be a problem.
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Post by ndkent » Sat Aug 17, 2019 2:35 pm

for what it's worth, I have a vintage AKS. I send voltage in the external input and trim it until it tracks. My unit was modified for a 5v gate. Alternately there are third party connectors to the multipin on the AKS. I've found when I trim for one VCO, if I send to the other the voltage droops if I pin the second one, so I always patch to two before trimming and turn the amplitude down if I'm not using the second one initially.

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Post by MindMachine » Sat Aug 17, 2019 9:21 pm

Thanks to the OP and papz for the link. I never knew such a cable existed!

:hail:
FS: Pedals and Euro modules, Delta Labs
viewtopic.php?f=74&t=233636&p=3287718&h ... e#p3287718

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Post by alexosm » Sun Aug 18, 2019 4:53 pm

You can also look at the digitana interfaces if you want to use midi or more complex control.

http://www.synthi.co.uk/

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Post by papz » Mon Aug 19, 2019 10:29 am

Pairing any Arturia device with an original EMS instrument would be shameful and disrespectful. :rage:
viewtopic.php?t=210623&highlight=
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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.

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Post by Umcorps » Mon Aug 19, 2019 3:26 pm

:tu:

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Post by blw » Mon Aug 19, 2019 5:38 pm

MindMachine wrote:Thanks to the OP and papz for the link. I never knew such a cable existed!

:hail:
There was an old Graham Hinton post on this topic cautioning against using the Jones plug for purposes like these, which I quoted below. Does anyone know if the Kenton cable has the 'correct circuitry' he suggests it needs?

Graham Hinton wrote:
Juanjocov wrote:But then Graham Hinton says that "the internal Key is not a voltage and injecting an external voltage to that point can destroy the FET in the Envelope". Are you talking about the 8 pin Jones jack keyboard input?
The Key input on the Jones plug is directly connected to the FET gate and other internal circuitry. There is no protection so should NOT be used as a general input that anything may be patched to. Especially if it can exceed the Synthi +12V/-9V power rails.
I saw that Kenton make EMS leads to connect their MIDI to CV interfaces to an EMS. This cables are 3x3.5 mono jacks to 8 pin Jones. Are these safe to use? I also saw a couple of youtube videos where they are using a MIDI to CV interface connecting it to the 8 pin keyboard input for cv and gate.
It could be done with the correct circuitry, but then you cannot use a DK or KS at the same time. It is not safe to assume that because something exists that it is done correctly, apart from EMS peripherals. Show me the circuit and I'll tell you whether it is or not, but never assume.
Which would be the best and safest way to use a MIDI to CV interface with a Synthi A?. I'm about to buy one from a friend, which by they way, according to him has a modification where the gate input was moved from the keyboard input to the control OUTPUT ch2.
That sounds like somebody doesn't know what they are talking about.
Graham, you said that is better to modify the EMS to conform to standard 1v/oct and Gate voltages. Is this modification something that SHOULD be done by you or Robin Wood? Or can be done by a good synth technician?.
All the information on my modifications site is provided precisely so that neither international shipping nor myself need be involved. Any competent technician should be able to follow the circuits and if not then don't let them touch it.
So, from what I understood from REwire and Makaton responses, if I want for example to modulate the Synthi filter with an Euro LFO, I just patch the LFO to the matrix or to the input 1/2 with a custom cable?
Connect the LFO to, say, Input 2 high level input and then patch Input 2 to Filter Freq on the matrix.
I guess with that modification plus the custom Euro to pin cables (or the ones from EMS with 100k resistor) I'll be all set, right?
You only need 3.5mm to 1/4" jack cables. The input amplifiers are really discrete inverting op amps with 100k (5%) feedback resistors, i.e. not very precise. There are 47k (5%) input resistors on the high level input jacks giving a gain of about 2. These could be changed for any other ratio. The pins of the Jones socket go to the nodes so putting 100k resistors in the cable just forms a unity gain inverter. You still need a fine adjustment if it is going to be used for a pitch CV.

Avoid going directly into the matrix with special pins, they are too rare and easily broken, so is the Prestopatch socket. Avoid special cables, you will lose it or use another by mistake.

The low level (mic) inputs are just fixed x200 (+46dB) gain and this is not the best way to make a microphone amplifier. Removing the capacitor from the jack sockets frees up two 1/4" jacks for use as CV and Gate inputs. This is the easiest and safest way to interface.
felixer wrote:BUT: do not expect any vcs3/synthi to be in tune at any time ... just sayin' ...
just sayin' out your backside...

The whole point about my mods is that any Synthi can easily be altered to be stable and track well over 7 octaves and plenty have been. Some Euro VCOs cannot do that...

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Post by Portabella » Tue Aug 20, 2019 4:21 am

papz wrote:Pairing any Arturia device with an original EMS instrument would be shameful and disrespectful. :rage:
viewtopic.php?t=210623&highlight=
I know about your story with Arturia and I compromise and dislike them for that. Neither do I like their synths. But after all I gotta say that the Keystep and Beatstep are great little bits of pieces for a great price that work very well with any equipment, apart from any consideration of being unethical

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Post by papz » Tue Aug 20, 2019 10:28 am

It's not "my" story only but a typical behaviour of Arturia that they consider normal.
Each one is free to put their ethical boundaries wherever they like of course.
I stopped using my Keystep despite it's good stuff for the price, see the Arturia logo printed on it made me want to throw up.
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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.

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Post by papz » Wed Aug 21, 2019 10:22 am

blw wrote:Does anyone know if the Kenton cable has the 'correct circuitry' he suggests it needs?
I've used and seen these Kenton cables and built similar ones myself, Digitana used to offer some in the past as well.
Many people use them and I never heard of any problem they may have caused. They are safe.
Inside the Jones plug are the 100k resistors in series with the CV input channels needed to prevent input amp saturation and a diode or transistor for the gate input.
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.

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Post by Scot Solida » Thu Aug 22, 2019 7:40 am

Despite having a DK2, I often use the Elektron Analog Keys to play (and sequence) my VCS3. It is an ideal companion for the Synthi. I usually use one of the AK’s CV outputs for triggers/gates (Papz’ sustained transient/external gate mod makes this even more useful), another for pitch, and another for other stuff I want to modulate. It can be great fun to set up a sequence like this, with the third AK CV output generating triggers to clock Papz’ S+H mod. I often run one or both of the VCS3’s outputs into the Analog Keys’ inputs for sync’ed delays or reverb.

The Analog Keys is a terrific controller for any old (or new) CV synth. The gates/triggers/CV are totally scalable and very flexible. It pains me that Elektron has discontinued it. Fortunately, you can get all the CV stuff from the desktop versions of the Analog Four.

My other favorite controller for the VCS3 is a Haken Continuum with the CVC box. This, too, is totally user-scalable using the Eaganmatrix software.

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Post by blw » Tue Sep 03, 2019 10:05 pm

papz wrote:Inside the Jones plug are the 100k resistors in series with the CV input channels needed to prevent input amp saturation and a diode or transistor for the gate input.
Thanks for the info! This sounds similar to Robin's recommendation for cv cables, and possibly the diode on the gate input is the gate mod he offers?

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Post by blw » Tue Sep 03, 2019 10:08 pm

Scot Solida wrote: The Analog Keys is a terrific controller for any old (or new) CV synth

My other favorite controller for the VCS3 is a Haken Continuum with the CVC box.
I'm going to need to look into both of these. Are you scaling the pitch cv on these devices instead of attenuating on the VCS3? Does it feel repeatable or do you need to calibrate each session? I've found pitch calibration on the Synthi to be a bit tedious for me. I would love another solution.

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Post by papz » Wed Sep 04, 2019 7:21 am

I modified many Synthis with precalibrated CV and gate inputs using the existing jack sockets, it's plug and play (and switchable to the original inputs), you just have to set the input level pot to 10 and use selected patch pins. I can also add buffers to prevent pitch drift when more pins are added into a row or column.
Feel free to pm me if you want me to do this on your Synthi, I'm located in Belgium.
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.

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Post by Scot Solida » Wed Sep 04, 2019 7:37 am

blw wrote:
Scot Solida wrote: The Analog Keys is a terrific controller for any old (or new) CV synth

My other favorite controller for the VCS3 is a Haken Continuum with the CVC box.
I'm going to need to look into both of these. Are you scaling the pitch cv on these devices instead of attenuating on the VCS3? Does it feel repeatable or do you need to calibrate each session? I've found pitch calibration on the Synthi to be a bit tedious for me. I would love another solution.
In the case of the Analog Keys/Analog Four, I usually tweak the scaling on the Elektron. When using the Continuum/CVC, I’ve made a preset patch with the desired voltage output and I fine-tune the scaling on the VCS3 itself. I don’t find either method to be tedious or difficult. But then I’ve never found the VCS3 to be as difficult to scale and tune as it’s reputation would suggest. Both of the above methods are as ‘repeatable’ as scaling the VCS3 for use with the DK2. It isn’t entirely ‘set and forget’ and it never will be, but it takes only a few minutes and then it behaves as it should with a few occasional tuning tweaks to allow for temperature changes over the session, etc

For clarification, I am only talking about tweaking the tuning of the oscillators and the input scaling. I don’t actually open the back up and re-calibrate the VCS3 before each session. Mine is internally calibrated quite nicely, and that only needs to be done very occasionally (usually when I have serviced or modified something).

EDIT: as Papz suggests, it’s easiest to get something like repeatable results with external scaling if you crank the VCS3’s Input level you’re using to to 10 and use selected pins. I actually have two of my red pins marked so that I know which ones to use for Osc 1 and Osc 2, respectively.

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Post by blw » Fri Sep 06, 2019 10:39 am

Great info, guys, thanks! I was planning to send my Synthi back to Robin for some additional mods. I'll get in touch with you papz when I am ready to do so to see if an additional stop on its holiday abroad can be arranged or if perhaps you can do everything I want anyway. I was judicious in my mod selection when I ordered. Now I pretty much just want them all.

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Post by MindMachine » Sun Sep 08, 2019 2:11 am

Received my Kenton convertor cable. Plan on trying ARP 3620 keyboard first and then Roland CSQ-600 sequencer.

Looks like I will need to be patient tuning it in with each use. Thanks all and will revisit this thread as reference.
FS: Pedals and Euro modules, Delta Labs
viewtopic.php?f=74&t=233636&p=3287718&h ... e#p3287718

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