EML 101/200/etc : Converters or Modifications for CV Control

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hellohihowareyou
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EML 101/200/etc : Converters or Modifications for CV Control

Post by hellohihowareyou » Sun Feb 27, 2011 11:31 am

Another topic surprisingly untouched...!

1. Does anyone know of a midi-cv converter that can output the 1.2v/oct scale that the EML series runs on?

2. Does anyone know of a techs that will modify the scaling to 1v/oct?
(I know they're out there because posters have mentioned it)

3. What other modifications have been done to the EML series?
(inverting the envelopes and adding a breakout box of additional patch points are both good ideas)

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Post by fluxmonkey » Sun Feb 27, 2011 11:39 am

george matteson is doing a massive EML refurbish, and i think has a pretty extensive knowledge of their guts, might check in w/ him
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Post by sandyb » Sun Feb 27, 2011 4:24 pm

iirc people here have mentioned that kenton midi-cv units can do 1.2v/oct

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Post by ndkent » Sun Feb 27, 2011 4:54 pm

Nope regarding Kenton for me, I had a pro Solo and still have a pro4 and neither quite got there. Some other brands like Encore will or maybe a model I didn't have. But if you have a voltage mixer on your modular you can use 2 mixer channels, one at 100% the other can be adjusted to get it to track.

The 101 was made over a bunch of years with some changes. Just mentioning that because the interfacing details might not be the same. The 200, which I don't have but doesn't seem that big a deal once you have something that can do 1.2v/oct. (Unless of course it's not actually 1.2v/oct?) The 101 seems trickier at least with the one I have. The envelope trigger responds properly to gate but as I recall only triggers one envelope. Also there is a Seq in - but as I recall it just went to half the VCOS though I could be wrong since it took me a while to decipher the voltage routing. FWIW I think some units don't have the SEQ IN, but I'm not sure. About 10 years ago I did mess around with the keyboard connector (some have 4 pins some more) and successfully got everything to track and play.
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Post by SMS303 » Sun Feb 27, 2011 5:20 pm

fluxmonkey wrote:george matteson is doing a massive EML refurbish, and i think has a pretty extensive knowledge of their guts, might check in w/ him
Mr. George Mattson is imo mr. EML :)

He helped me very friendly and really fast with the EML circuit VCA & VCF pcb's. problems i had :tu:
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Post by mmm » Sun Feb 27, 2011 6:44 pm

SMS303 wrote:
fluxmonkey wrote:george matteson is doing a massive EML refurbish, and i think has a pretty extensive knowledge of their guts, might check in w/ him
Mr. George Mattson is imo mr. EML :)

He helped me very friendly and really fast with the EML circuit VCA & VCF pcb's. problems i had :tu:
That's because I had the documents you needed :)

I had to turn him down. I never modified either my 200 or my 101. Yes, I know their design logic well but, I don't consider myself an expert. I can make suggestions on what to do but, I really don't have the time and the space to actually do the mods for anybody. Besides, if I fry my gear, shame on me. I don't know if I can handle the shame if I fry someone elses gear.

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Post by dslocum » Tue Mar 15, 2011 4:52 pm

I might be able to help. I was EML's New Jersey Sales & Service rep way WAY back when in the 70's. I've modified several 101's for folks.

I LOVE those machines. Lots of fine memories

Getting the 1.2v/Oct output is not a big deal - the question is if you want to modify the 101 (down-grading it's value) or use an external box.
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Post by PrimateSynthesis » Thu Mar 17, 2011 7:13 pm

It's easy to build a circuit that can go from 1V/Oct to 1.2V/Oct, or vice versa, for Buchla, EML, etc. It was a popular mod to add better CV control to the Mini Moog. It's basically just a dual op-amp (an LT1013 would be an excellent choice) and and a couple of multi-turn trimpots (one to adjust the offset, the other to adjust the scaling).

These were great for building them:
http://www.cgs.synth.net/modules/cgs70_mix.html
but for some inexplicable reason it says they are discontinued.

But you could still just use a little piece of perfboard.

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Re: EML 101/200/etc : Converters or Modifications for CV Con

Post by noobyscooby » Wed Jun 22, 2011 7:14 pm

hellohihowareyou wrote:Another topic surprisingly untouched...!

1. Does anyone know of a midi-cv converter that can output the 1.2v/oct scale that the EML series runs on?

2. Does anyone know of a techs that will modify the scaling to 1v/oct?
(I know they're out there because posters have mentioned it)

3. What other modifications have been done to the EML series?
(inverting the envelopes and adding a breakout box of additional patch points are both good ideas)
1) I have a Philip Rees that I've always loved but love it even more once I found out that it works like a charm with my newly acquired EML 100. The highest you can go is 1.2 so you crank it to the right and you're good. At least sounds good to me. Will have to try and Soundcloud something soon. Maybe with the Tetra Maps... Kyle Jarger might make you one of his boxes if you are really nice to him. I asked when my EML 100 was on the way and he said he still had enough parts to build one if I really wanted one. I believe he built and EML specific one for Cornutt. Much more than your average MIDI/CV convertor but I am happy with my Phillip Rees for now and in a studio where I have too much crap the footprint is nice.

2) Unless it involves mangling the hell out of the keyboard mechanism and/or the keyboard attachment plug I haven't seen one. I would never want my plug or keyboard bothered with. For me the keyboard controls and how it interacts with the synth is one of the best things about the 100.

3) I have two very useful ones for my 100 that were done when the previous owner had restorations done. On a 101, the filter sweeps from -1 to +3. On a 100, it only sweeps -1 to +1 but there is a filter octave switch that goes an additional -1 to +1, so -2 to +2 total. My filter was opened up to go another octave lower and another octave higher so mine's -3 to +3 now. The octave lower comes in really handy at smoothing things out.

The other mod is that on a 100, there is pink and white noise with seperate outputs and a knob that sweeps to either one. On mine now it sweeps from white to OSC 1 output instead of pink. Very useful as now you don't have to patch OSC 1 into the filter mixer and can use something else externally as on the 100, the external input on the filter mixer is paired with OSC 4. The pink output jack is also now an additional OSC 1 which can be quite handy given its LFO capabilities.

I have only had my 100 a few weeks but am really enjoying it. Glad I took the plunge into EML land. I don't care about its phatness or the 1.2v/oct business as I'm sure most EML people don't. I have other much more conventional synths to do conventional things with.

Dslocum! What are all the mods you have done/seen? If I ever have the nerve to put it in the mail it would be cool to know what some other things could be possible. The modulator I can compensate with patching and don't mind using an external S&H but would be cool to know what other things were possible.

Awesome site and history by the way. A lifetime in synths.

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Post by jkjelec » Tue Jun 28, 2011 8:34 am

Thanks for your kind words noobyscooby! One correction; no one needs to be nice to me to get a JKJ MIDI/CV converter...they just need to send money and wait a month or so!

I had an EML101 a few years ago; when I had first received it and was playing with it, all of a sudden I thought I heard reverb...a little further exploration, and I found taht this unit had a reverb tank added in! I think it used the external input knobs/jacks. I had heard the EML had lots of factory mods/customizations available; this mod was incredible (and not labeled/well hidden)!

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Post by AntManBee » Tue Jun 28, 2011 9:14 am

I contacted Kenton when I first got my 101 and John thought that he could build a MIDI to CV converter in that would work with the 1.2v/oct. In the end I realised I had no interest in MIDI and left my 101 as it was, not least because it's in very good original condition.

There are other significant issues if you try to control the 101 from an external CV/Gate source, most significantly, that not all the VCOs can be controlled unless you build an interface which uses the (obsolete) keyboard socket.

It's worth joining the EML Yahoo Group although, as you might imagine, it's not very active, but there is archived information there which might be of interest. Also Dave Cornutt's page on the 101 is interesting and informative: http://home.hiwaay.net/~cornutt/Music/W ... e/EML.html

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Post by noobyscooby » Tue Jun 28, 2011 6:13 pm

Couldnt you just control them all by setting the oscillator controls to mix or /mix then feeding the cv into the osc control and adjusting the osc4/ext pot in the osc control section?

I have a 100 though not a 101 so things are a little different. For instance there's a mix option for each osc control so they can be ganged.

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Post by REwire » Sat Jul 02, 2011 8:40 am

The only input on the 101 that controls all four oscs is not 1.2v/oct but actually 3.2v/oct in use. Amping up CV to that level could be dangerous s o I never tried it. Did try to do midi multiplication in my sequencer to get an octave or so of tuning.

Modification is the only way to do it and I know it's been done but I'd rather just keep it original.

Dan

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Post by blz » Wed Jul 06, 2011 5:14 pm

i got a mod done by ed miller that makes it work with 1 volt per octave
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Post by woodteeth » Thu Jul 07, 2011 9:53 am

inaresing stuff on this thread. my 200 defs doesn't appear to track at 1.2 volts per octave with my kenton pro-solo set properly.
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Post by daindain » Thu Jul 07, 2011 7:49 pm

I don't know if my memory serves me well. But when I had my MS20 I remember that tracking correctly with the 200. I could be remembering that wrong though. :hmm:

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Re: EML 101/200/etc : Converters or Modifications for CV Con

Post by kaoss » Sun Jul 10, 2011 12:59 am

hellohihowareyou wrote:Another topic surprisingly untouched...!

1. Does anyone know of a midi-cv converter that can output the 1.2v/oct scale that the EML series runs on?
Kenton Pro 2000 MK2 can do 1V/Oct, Hz/V and 1.2V/Oct
hellohihowareyou wrote:2. Does anyone know of a techs that will modify the scaling to 1v/oct?
(I know they're out there because posters have mentioned it)
Dean Batute in Toronto did this mod on my 101s. (t's easily reversible back to 1.2V/Oct)

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Post by kaoss » Sun Jul 10, 2011 1:11 am

ndkent wrote:FWIW I think some units don't have the SEQ IN, but I'm not sure.
You're correct, some don't - there's CM3 Output instead (Control Mode 3)

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Post by belltones » Wed Aug 07, 2019 10:24 am

I know this is an old thread but in case anyone is ever looking for this again--
My workshop now sell PCBs and kits of a circuit we designed to do this conversion that anyone who can solder can easily install in any EML-101 or 100. Either the Sequencer input jack or what was previously the CM3 output jack (depending on the version)becomes a 1V/Octave input to control voice 2 (Oscillators 3 and 4).

It does not require any new holes to be drilled or a switch to be added, and allows voice 2/Oscs 3 and 4 to function 100% normally when no external CV is plugged in.

Details here: http://www.belltonesynthworks.com/blog/ ... available/

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