Minimoog/Kenton Pro II

[Dave Bryce]

I have a Kenton Pro II CV to MIDI converter doing nothing in one of my drawers. Had it for the Macbeth M5 I sold a few years back, and just put it away. Now that the Mini is fully functional again, time to break out the Kenton...

 

I need an S-trig to 1/4 mono cable, but I found that easily - it'll be here next week. I have a question about the Aux1 control, though. I might want to try routing velocity from my controller keyboard to control the filter instead of the loudness.

 

Does anyone have a Mini/Kenton combo? If so, have you tried using the Aux to control either loudness or filter?

 

dB

[Markyboard]

Don't have the Kenton Dave but it should be straight forward. I do similar with my small modular midi-cv converter and it works great. You might find this link of use if you have problems.

 

 

[Dave Bryce]

Don't have the Kenton Dave but it should be straight forward.

It appears to be. The big trick is apparently setting the Kenton so it knows the zero note is an F, not a C.

 

The Kenton lets me set upper and lower ranges, as well as a reset value. Should really be more a matter of dialing it in on the Mini's end, I think.

 

dB

[Markyboard]

Don't have the Kenton Dave but it should be straight forward.

It appears to be. The big trick is apparently setting the Kenton so it knows the zero note is an F, not a C.

 

The Kenton lets me set upper and lower ranges, as well as a reset value. Should really be more a matter of dialing it in on the Mini's end, I think.

dB

 

 

Then again why else would midi controllers have transpose functions? :idk

 

[The Real MC]

There's two problems with using a conventional MIDI->CV converter with the Minimoog. One, you must periodically press a key on the Minimoog keyboard; the reason is the keyboard has its own sample & hold that doesn't hold the pitch CV forever, it actually discharges slowly, resulting in off-pitch MIDI notes that go flatter with time. Not a fault, it's a consequence of the original design. So you have to "refresh" the S&H by pressing a key on the Minimoog keyboard. Actually this is true of any analog keyboard that employs a S&H to hold the pitch CV.

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

The Lintronics Minimoog MIDI retrofit solves all of these problems. I've had one in my RAM since 1996.

[Dave Bryce]

There's two problems with using a conventional MIDI->CV converter with the Minimoog. One, you must periodically press a key on the Minimoog keyboard; the reason is the keyboard has its own sample & hold that doesn't hold the pitch CV forever, it actually discharges slowly, resulting in off-pitch MIDI notes that go flatter with time. Not a fault, it's a consequence of the original design. So you have to "refresh" the S&H by pressing a key on the Minimoog keyboard. Actually this is true of any analog keyboard that employs a S&H to hold the pitch CV.

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

The Lintronics Minimoog MIDI retrofit solves all of these problems. I've had one in my RAM since 1996.

I guess I'll find out soon enough. The advantge of the Kenton is that I already have it.

 

dB

[Markyboard]

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

 

Unless you tie your CV into the Keyboard Pitch Bus input, i.e. the same place the mini's keyboard ties into .

[Markyboard]

Also doesn't the Kenton have it's own glide function?

[Dave Bryce]

Also doesn't the Kenton have it's own glide function?

Yes, I believe it does.

 

dB

[RABid]

There's two problems with using a conventional MIDI->CV converter with the Minimoog. One, you must periodically press a key on the Minimoog keyboard; the reason is the keyboard has its own sample & hold that doesn't hold the pitch CV forever, it actually discharges slowly, resulting in off-pitch MIDI notes that go flatter with time. Not a fault, it's a consequence of the original design. So you have to "refresh" the S&H by pressing a key on the Minimoog keyboard. Actually this is true of any analog keyboard that employs a S&H to hold the pitch CV.

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

The Lintronics Minimoog MIDI retrofit solves all of these problems. I've had one in my RAM since 1996.

 

This is one reason I like this forum. You never know when you are going to learn something interesting.

[Dave Bryce]

This is one reason I like this forum. You never know when you are going to learn something interesting.

..and why it's usually a pretty good idea to ask even really specific questions to which no one may know the answer.

 

It never ceases to amze me how much combined knowledge exists here.

 

dB

[Markyboard]

Well there's also a down side. I'm seriously gassing for a Pro 2000 mk II now. Thanks.

[The Real MC]

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

 

Unless you tie your CV into the Keyboard Pitch Bus input, i.e. the same place the mini's keyboard ties into .

 

A better solution is to re-design the rear panel pitch CV jack so that the keyboard CV is normalled to the VCOs, then if you plug a converter the keyboard CV is disconnected. If I recall, the rear panel pitch CV is not quite 1V/oct, which can be remedied if the converter's output can be scaled.

 

Also doesn't the Kenton have it's own glide function?

Yes, I believe it does.

 

dB

 

It may have on-board glide but the Minimoog glide circuit is peculiar. Besides its not-quite-linear glide rate, the rates between up and down are different. That contributes to its unique expression.

[Markyboard]

 

The biggest problem is the CV from the converter is NOT processed by the glide processor.

 

 

Unless you tie your CV into the Keyboard Pitch Bus input, i.e. the same place the mini's keyboard ties into .

 

A better solution is to re-design the rear panel pitch CV jack so that the keyboard CV is normalled to the VCOs, then if you plug a converter the keyboard CV is disconnected. If I recall, the rear panel pitch CV is not quite 1V/oct, which can be remedied if the converter's output can be scaled.

 

Exactly - I didn't want to re-hash all that detail but I posted on it here last year.

[Dave Bryce]

Well there's also a down side. I'm seriously gassing for a Pro 2000 mk II now. Thanks.

I cannot be held responsible for your geeky tendencies.

 

dB

[Markyboard]

Well there's also a down side. I'm seriously gassing for a Pro 2000 mk II now. Thanks.

I cannot be held responsible for your geeky tendencies.

 

dB

 

Damn, the search continues.

[The Real MC]

Well there's also a down side. I'm seriously gassing for a Pro 2000 mk II now. Thanks.

I cannot be held responsible for your geeky tendencies.

 

dB

 

Damn, the search continues.

 

Your mother always warned you about hanging around bad influences...

[analogholic]

I use the Kenton Pro Solo mkII with my Mini D.

I route aux so it controls filter and/or amp via velocity.

Works like a charm.

 

[Dave Bryce]

I use the Kenton Pro Solo mkII with my Mini D.

I route aux so it controls filter and/or amp via velocity.

Works like a charm.

Way cool.

 

Which is more fun, filter or loudness?

 

dB

[Al Coda]

 

The Lintronics Minimoog MIDI retrofit solves all of these problems. I've had one in my RAM since 1996.

 

I want one, but the kits seem to be out of stock unfortunately.

 

I got several of the issues described eliminated by other mods on my Mini, but the "lack of Glide" issue is still present when using my Roland MPU-101.

 

A.C.

[Markyboard]

Well there's also a down side. I'm seriously gassing for a Pro 2000 mk II now. Thanks.

I cannot be held responsible for your geeky tendencies.

 

dB

 

Damn, the search continues.

 

Your mother always warned you about hanging around bad influences...

 

She did indeed...Michael.

[Markyboard]

I got several of the issues described eliminated by other mods on my Mini, but the "lack of Glide" issue is still present when using my Roland MPU-101.

 

A.C.

 

I'm fairly certain you lose the filter keyboard tracking as well when using the standard Oscillator CV input.

[Al Coda]

I got several of the issues described eliminated by other mods on my Mini, but the "lack of Glide" issue is still present when using my Roland MPU-101.

 

A.C.

 

I'm fairly certain you lose the filter keyboard tracking as well when using the standard Oscillator CV input.

 

Mine is modded and here´s how:

 

Since the MPU-101 offered dedicated CV outputs for,-

 

1.) Pitch, 2.) Dynamics (velocity), 3.) Gate

 

per voice,- it has 4 MIDI/CV channels ...

 

and global controller output CVs:

 

a) Bender, b) Modulation, c) After Touch, d) Volume

 

I needed more inputs on the Minimoog D !

 

I got dedicated Pitch-CV and Gate Ins and Outs and a dedicated "modulation" CV input in addition to the stock Pitch-, Filter-Cutoff and Loudness CV inputs.

 

That way I´m able to connect Pitch-CV and Gate from MPU-101 to the "dedicated"/ custom CV and Gate (+5V instead switch trigger) inputs on the Minimoog D.

In addition, a rotary-switch mounted to the left-hand-controller and where originally the "decay" ft-sw. connector is located, allows realtime toggle switching between keyboard operation and back panel Pitch-CV/Gate control on the fly.

(For "Decay" I now use the rocker switch only !)

 

So, the MPU-101 can be connected always as also receive MIDI and output CVs while that toggle switch decides what´s been used actually.

 

The "lowest key voltage note interpretation issue" (0 volts = C or F) is eliminated in my Minimoog D and I also don´t have to retrigger keys as described for non-modded Minimoogs above.

 

For the custom Pitch-CV and Gate I/Os, there´s some circuitry inside the Mini allowing separate tuning/scaling to incoming MIDI, so the (independent) tuning/calibration for original keyboard CV and CVs generated by the MPU-101 is very close, even not 100%, when calibrated correctly.

But now it´s all aged a bit, changes over time and needs calibration more often.

I got those mods already in the 80s.

 

Now, when the original CV inputs are still free, I connect MPU-101 "modulation" to the custom/dedicated "modulation" CV input on my Mini, "Bender" to the stock Pitch CV input and at least "Dynamics" to the Cutoff or Loudness CV inputs.

 

Since I use MOOG 1120 CV pedals, I prefer connecting one to the "Cutoff CV" input and leave "Dynamics" from MPU-101 for "Loudness" remotely controlling the Minimoogs overall volume over MIDI when playing it from a different keyboard.

 

There are different scenarios though and all can be re-patched on demand.

I rarely connect the channel AT CV output to the Mini since I disliked the curve.

I´d like to get some CV-mixer to connect multiple CVs to one modulation target, p.ex. "dynamics" and AT-CV from MPU-101 as well as a MOOG 1120 pedal to "cutoff" CV-Input on the MOOG, but needed some instructions to build one correctly.

 

Since I moved, my Mini is in it´s case, but AFAIR, my filter tracking rocker switches work when I remotely control the Mini over MIDI (and I know that´s not normal and possibly the result of the mods I already have).

 

The Glide doesn´t ...

But I will show my tech the mods I found here in the forum and I believe we can fix that too, since I´ve seen your mod defeats the keyboard when there´s a plug in the Pitch-CV input,- and that is what my rotary switch mentioned above does too.

So, there might be a different wireing trick you did and I don´t have.

 

But since the MPU-101 is long in it´s teeth, I´d prefer getting the Lintronics interface and don´t think about the Minimoog´s keyboard contact springs condition, bussbars alignment and cleaning for some time.

In fact I´d like to make it a keyboardless fully working expander, nonetheless keeping the keyboard, refurb it separately when there´s enough time available and have the keyboard w/ LH-controller it in a separate case and some multicore cable for connectivity.

 

A.C.

[Markyboard]

Shewww - had to go through that twice! Very cool Peter.

 

Having independent tuning for your custom pitch CV input is awesome. As you may have seen I implemented Michael's (The Real MC's) mod to have the mini's own keyboard operate at 1V/Octave. This way the scaling is common to most midi-cv inputs working to that standard. I never resolved the key 0 offset between internal keys and external but it's easy to transpose my incoming midi. I actually do this on the Reaper track dedicated to the mini's midi channel as opposed to the controller itself.

 

 

Now you mentioned wanting a CV mixer and the Linntronics midi module. I'm wondering what this gives you over a small Eurorack module with a midi interface and CV mixer, VCAs etc or a Kenton interface which gives you many CVs to play with. What else does the Linntronics do?

[The Real MC]

 

The Lintronics Minimoog MIDI retrofit solves all of these problems. I've had one in my RAM since 1996.

 

I want one, but the kits seem to be out of stock unfortunately.

 

Why is it always the good stuff that is out of production?!?

 

What else does the Linntronics do?

 

- Can play the Minimoog from its own keyboard or over MIDI without previous CVs affecting the pitch.

- Five plus octave range over MIDI.

- MIDI notes are processed by Minimoog glide.

- Filter can track MIDI notes through the switches.

- Dedicated LFO with waveforms (including reverse ramp, S&H, and negative polarity) and rate configured over MIDI.

- Available MIDI controls for modulation to filter and/or volume: note velocity, mono AT, breath controller, foot controller.

- MIDI note assignment & note priority configurable w/MIDI (even inverted keyboard tracking)

- MIDI CC for volume, filter cutoff, glide on/off, sustain pedal, pitch bend (configurable bend ranges), mod wheel (THE wheel itself!).

- No new holes needed for the front panel. Rear panel requires installation of a MIDI IN jack and switch to toggle between noise or dedicated LFO. This is then routed to the front panel modulation mix, where you can still use VCO3 as a modulator mixable with noise or LFO.

- Multiple Lintronic-equipped Minimoogs can be configured as a polyphonic system.

 

One minor con: on bootup it defaults to MIDI ch#1, but this can be reconfigured over MIDI.

 

I *love* routing MIDI note velocity to filter cutoff and playing from a weighted action MIDI controller.

 

Oops I'm playing the bad influence again

[Dave Bryce]

Remember, mine's not a stock unit - it's got a whole set of mods that had even Ken Rich scratching his head a bit (mainly the two switches that reroute the filter contour to oscs 2/3).

 

http://i5.photobucket.com/albums/y172/davebryce/MiniClose.jpg

 

Apparently Ron Rivera did some interesting rewiring to get those all to work Will be interesting to see what happens when I add the Kenton.

 

...and for those of you who may not have seen my Mini before...yes, that signature is authentic.

 

http://i5.photobucket.com/albums/y172/davebryce/Mini.jpg

 

dB

[Markyboard]

Interesting - thanks for the Linntronics run-down. Somehow this escaped me in its hey day. The low/high note priority is cool. Otherwise I've grown fond of talking to Sarah when I need a connection patched.

 

[Markyboard]

...and for those of you who may not have seen my Mini before...yes, that signature is authentic.

 

http://i5.photobucket.com/albums/y172/davebryce/Mini.jpg

 

dB

 

Clone that...Beotch!

[Dave Bryce]

Clone that...Beotch!

Not today, bud...

 

dB

[Al Coda]

Having independent tuning for your custom pitch CV input is awesome.

 

It has a "price" !

Since I have it, the Mini´s master tune control must be set somewhere between 10 and 11:00h instead ideally being set to 12:00h for A-440.

 

As you may have seen I implemented Michael's (The Real MC's) mod to have the mini's own keyboard operate at 1V/Octave. This way the scaling is common to most midi-cv inputs working to that standard.

 

Yes, that´s very interesting and I hope I can add that to my Mini near future.

Up to now, what I have is all kind of compromize calibration/tuning to get the balance between CV produced by keyboard and CV produced by ext. interface.

 

I never resolved the key 0 offset between internal keys and external but it's easy to transpose my incoming midi. I actually do this on the Reaper track dedicated to the mini's midi channel as opposed to the controller itself.

 

In the past, when we started modding my 3 Minimoogs, there were no DAWs, only little analog step sequencers.

When MIDI appeared and there was MIDI/CV conversion available, that was it for me and I experimented w/ all kind of synth combinations and the MPU-101, which had interesting voice assignment and trigger modes.

B.t.w., on my MPU-101, the pitchbend range, normally fixed value +/- 1Oct., is continuously variable (+/- 0-12 semitones).

 

According to the key 0 offset, I dunno exactly how it´s realized in my Mini.

1st, I had a simple switch. It´s still there but deactivated because I wanted it automatic, which I got.

I think it came w/ that "scaling-compensation" circuit for the additional CV/Gate inputs.

 

Now you mentioned wanting a CV mixer and the Linntronics midi module. I'm wondering what this gives you over a small Eurorack module with a midi interface and CV mixer, VCAs etc or a Kenton interface which gives you many CVs to play with. What else does the Linntronics do?

 

Well, some simple passive "CV-mixer" (3 inputs max./ 1 out) I´d want for the Minimoog alone as long as I don´t have a chance to get the Lintronics LMC.

I think about a little box w/ four 1/4" jacks and 3 pots, but it should not do anything unexpected or negative to the Mini´s behaviour.

 

Unfortunately the LMC is not only out of stock, it´s out of production!

 

In fact, the LMC would make a lot of my aged mods obsolete and I´m pretty sure it allowed connecting a CV pedal to the stock filter cutoff input while velocity (and probably AT too) affect the cutoff simultaneously.

 

But w/ the MPU-101, it´s a different story because there´s the CV-cable snake and all the connectors vs. a MIDI cable only w/ the LMC built in and internally connected.

 

The Kenton has advantages over the MPU-101, but it´s also external.

 

For me, the real advantage would be to have the interface internal.

The LMC (you already got the details in a post above) would be ideal and I´m a idiot not buying one earlier when it was easily available in the 90s.

 

A.C.