MOTM

Howdy folks,

I just wanted to drop a line about something I found out after the fact. As
you know, I started my MOTM system recently. For my Midi to CV solution, I
ended up choosing the Encore Expressionist. It turns out that there is a
compatibility issue with the MOTM-800s to be aware of. I'm posting this for
those of you who haven't made a decision yet, so that your decision can be
an informed one.

Turns out the Expressionist sends only gates, not separate gates and
triggers as I'm informed the Kentons do. This means I won't be able to get
true ADSR response out of a stock MOTM-800 when hooked to the Expressionist.
FYI, the Expressionist handles "multi triggering" by forcing the gate off
momentarily when it gets a new MIDI note on the same output channel.

I'm not terribly disappointed, since I still think the Expressionist's 8
full CV/Gate channels and 3 synchable LFOs win against the Kentons feature
for feature. Also, Tony sez he's adding a 4th LFO and real time LFO freq.
control in the next software rev!

I'm planning (when I get the time) to stick a little daughterboard on my
800s with a 555 one shot, to derive a trigger signal from the incoming gate.
The trigger output will connect to the normalling lug of the trigger jack,
so that it is defeated if you plug an external trigger signal in. Also, I'm
pretty sure I'll stick a transistor driver on this board for a gate lamp. I
just can't live without my gate lamps! If I get really ambitious, I may add
a small circuit to support a manual gate pushbutton, with some debouncing.

This will give full ADSR capabilities from my Expressionist, but also if I
gate from any external signal like a sequencer stage output, an LFO, etc.
BTW, Paul tells me that all this stuff is already built in to the new VC EG
he's planning.

I may post the mod when complete if there is interest - just don't expect
anything for a few weeks.

So, be aware of this issue if you consider an Expressionist.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

Dave Bradley wrote:

>
> From: "Dave Bradley" <daveb@...>
>
> Howdy folks,
>
> I just wanted to drop a line about something I found out after
> the fact. As you know, I started my MOTM system recently. For
> my Midi to CV solution, I ended up choosing the Encore
> Expressionist. It turns out that there is a compatibility issue
> with the MOTM-800s to be aware of. I'm posting this for those of
> you who haven't made a decision yet, so that your decision can
> be an informed one.
>
> Turns out the Expressionist sends only gates, not separate gates
> and triggers as I'm informed the Kentons do. This means I won't
> be able to get true ADSR response out of a stock MOTM-800 when
> hooked to the Expressionist.

I just assigned 2 voices to each midi channel, and used an
s-trigger on the second voice. This works.

Regards,

Roy Tate
roytate@...
http://www.ionet.net/~roytate

> I just assigned 2 voices to each midi channel, and used an
> s-trigger on the second voice. This works.
>
> Regards,
>
> Roy Tate

Thanks for the tip - I'll try it! I'll probably still do the mod, but this
would sure make it less urgent. Once I get up into 8 oscillator territory,
I'll want to free those channels up.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

Some time ago I encountered the same problem with my MIDI-CV and fixed it as outlined below. I posted the message below on 2-10-99.

-----Original Message-----
From: John Speth [mailto:johns@...]
Sent: Wednesday, February 10, 1999 9:35 AM
To: MOTM List
Subject: MOTM modifications suggestions...


I'd like to share a couple of MOTM modifications that I found useful. Both are simple and useful.

M120: Socket U3 (74HC08 quad AND) and experiment with using a 74HC86 (quad XOR) instead. The two devices are pin compatible. Just make sure you use a 74HC86. I used a 74HCT86 from Radio Shack and it worked fine. The reason for the change was that I was sometimes bothered by the fact that, for low frequency signals on one of the inputs, the counter would sometimes (1 in 16 chances) come to rest at all 0s and, therefore, completely silence the output. Using an XOR assures this can't happen. The sound is definitely not as complex as with using AND gates but it does have a different character.

M800: Solder a wire from the collector of Q1 to the unused pin of the trigger jack. I tack soldered a wire from R1 on the component side to J2 and tie-wrapped it down. This allows the EG to function as a complete ADSR with only a gate signal and no trigger. It will function as shipped when a trigger plug is inserted. I'm surprised this wasn't designed in. I wonder if it might be better to use a series resistor of about 5K in this wire to protect against transients when inserting and removing a trigger plug.

Does anybody else have any useful mods?

John Speth
Object Engineering, Inc
mailto:johns@...

Another comment on this subject ...

I have an inverter module in my ARF/DIY modular collection, and
if I patch a gate through the inverter first, it triggers just
fine. No good for 4 or 8 voice polyphonic work, but great for
single note stuff.

So there are two non-invasive solutions to the gate/trigger
dilemma:

1) Program every other voice on the Encore Expressionist
as a s-trigger with maybe a modulation CV instead of note info.

2) Run the gate through an inverter and then into the trigger

I would love a hardware solution, but John Speth's mod didn't
work for me. (Sorry John!) Maybe I just fumbled the mod ...
Perhaps a line drawing would help. If someone would send me
a drawing of their modification, I'd put it up on my web page
and post it here. (To avoid attaching images to mailing list
traffic).

Regards,

Roy Tate
roytate@...
http://www.ionet.net/~roytate

I tried the S-trigger trick last night, works fine for me!

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> -----Original Message-----
> From: Roy Tate [mailto:roytate@...]
> Sent: Wednesday, March 24, 1999 11:06 PM
> To: motm@onelist.com
> Subject: [motm] Re: Encore Expressionist compatibility with MOTM/
> MOTM-800 mods
>
>
> From: Roy Tate <roytate@...>
>
> Another comment on this subject ...
>
> I have an inverter module in my ARF/DIY modular collection, and
> if I patch a gate through the inverter first, it triggers just
> fine. No good for 4 or 8 voice polyphonic work, but great for
> single note stuff.
>
> So there are two non-invasive solutions to the gate/trigger
> dilemma:
>
> 1) Program every other voice on the Encore Expressionist
> as a s-trigger with maybe a modulation CV instead of note info.
>
> 2) Run the gate through an inverter and then into the trigger
>
> I would love a hardware solution, but John Speth's mod didn't
> work for me. (Sorry John!) Maybe I just fumbled the mod ...
> Perhaps a line drawing would help. If someone would send me
> a drawing of their modification, I'd put it up on my web page
> and post it here. (To avoid attaching images to mailing list
> traffic).
>
> Regards,
>
> Roy Tate
> roytate@...
> http://www.ionet.net/~roytate
>
> ------------------------------------------------------------------------
> We are proud as punch of our new web site!
> http://www.onelist.com
> Onelist: The leading provider of free email community services
>

> 1) Program every other voice on the Encore Expressionist
> as a s-trigger with maybe a modulation CV instead of note info.
>
> 2) Run the gate through an inverter and then into the trigger
>
> I would love a hardware solution, but John Speth's mod didn't
> work for me. (Sorry John!) Maybe I just fumbled the mod ...
> Perhaps a line drawing would help. If someone would send me
> a drawing of their modification, I'd put it up on my web page
> and post it here. (To avoid attaching images to mailing list
> traffic).
>
> Regards,
>
> Roy Tate

So my mod didn't work, huh? That's strange. I analyzed and tested this thoroughly.

My analysis (and confirmed through testing) showed that it's actually the falling edge of a short trigger pulse (normally at logic 0V) that will trigger the 555 timer. The rising edge has no effect. So that's why inverting the gate and running the output to the trigger will work. If you look at the circuit diagram, the first transistor (Q1) at the gate input just inverts the gate which is exactly what you need and exactly what you confirmed to work. The trigger input cap "pulsifies" the gate and makes it look like a trigger pulse.

There's no sense in using an outboard inverter when there's one built in. You musta "fumbled the mod".

Note that you have to make the trigger pulse sufficiently short so that your ear can't tell the difference in timing between the rising edge and the falling edge.

John Speth
Object Engineering, Inc
mailto:johns@...