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Modcan Quad Env + Klee
MUFF WIGGLER Forum Index -> 5U Format Modules Goto page 1, 2  Next [all]
Author Modcan Quad Env + Klee
haricots
I'm not sure if this should be in 5U or SDIY.

I just received a Modcan Quad Envelope today. Before I bought it I asked Bruce if the Quad Env would work with a Klee which outputs 10v gates. He said it would be fine. However, it seems that the gate from the Klee doesn't always fire off the envelopes. Almost as if the pulses aren't wide enough. seriously, i just don't get it

Interestingly enough, I have better luck using the trigger outs on the Klee. I'm using my Machinedrum to clock the Klee so I'm wondering if this is where the problem lies. Any ideas?
babysealclub
Does the problem only occur when clocking from the Machinedrum? Will it happen if you clock the Klee with the Step button?
haricots
Hi Todd. Will try that next. It does however gate fine with the MOTM-650 and a SA Tetra MAPS. I'll try sending a pulse from something other than the Machinedrum. I've always thought the pulses from the MD were a little weak (judging by the intensity of the gate LEDs). My (now since sold) analogue EG's seem to not care.
sduck
While the klee produces gates and triggers when you press the step button, I think that once you patch in a clock signal of whatever type that overrides the built in gate/trig. So if the machinedrum has a low clock output, you'll get a low output from the gates and triggers on the klee.

It looks like the 60b will trigger at around 4v, which is kind of high - is there a setting on it which will reduce the amount of trig/gate voltage required? Or alternately there might be a way to kick up the MD clock signal before it reaches the klee - I've used a VCS for this, and a motm 510.
bar|none
> I think that once you patch in a clock signal of whatever type that overrides the built in gate/trig.

Yes, the length of the gate that you provide into the clock IN is the gate length coming out. Which is actually super cool, since if you have a clock like the Flame clockworks, you can vary the gate length on the clock for a gate effect.

Juts read the KLEE manual cover to cover so this is fresh in my mind.
haricots
babysealclub wrote:
Does the problem only occur when clocking from the Machinedrum? Will it happen if you clock the Klee with the Step button?


Ok, so the problem still exists when pressing the Step button. Maybe the MD clock input is still interferring. I will have to try again tonight.

Using the trigger outs instead of the gates works perfectly.

Gates from my Tetra MAPS or my MOTM-650 works perfectly.

So either the MD is a crappy clock source, or the Klee and the Quad Env don't like each other.

I'll try different clock sources, boosting/reducing gate levels and see what happens.
Scott Stites
The gate outputs should stay high as long as the manual step switch is pressed. The trigger outputs, however, don't and are pretty dang narrow (1 ms or so). Did you build the Klee yourself? I can show you how to widen out the pulses if you'd like. It's just a matter of changing capacitor values.

Cheers,
Scott
Scott Stites
Oh - OK, just re-read and the trigger outputs are working for you. I'll have to think about what the gate prob could be a bit more.....
haricots
yeah, strange that a narrower pulse works more reliably. Let me restate that I never had this problem with my MOTM or Oakley EG's. My Klee (built by Todd F) is configured for 10V gates. Could this be the issue?
Scott Stites
OK, I'm thinking the MD clock pulses may be too thin for using the gate out.

Bar None is right - the gate output will only stay high as long as the clock input is high. The trigger is a one shot that will stay high for 1 ms as long as it sees a high coming into the clock input past the internal threshold of around 2V (12V operation) or 2.5V (15V operation). If the input signal exceeds that level, the gate/trigger levels should be at the level the Klee was built for.

Still wouldn't explain why manual step gate out doesn't play nice with the EG, though.
Scott Stites
haricots wrote:
yeah, strange that a narrower pulse works more reliably. Let me restate that I never had this problem with my MOTM or Oakley EG's. My Klee (built by Todd F) is configured for 10V gates. Could this be the issue?


Maybe(?) - I guess the easiest way would be to try attenuating the output of the gates to see if that makes a difference.
haricots
The threshold of the Modcan Quad Env is 4v. The MOTM-800 is 1.5v.

I'll have to play around again tonight without the MD as the clock source.
haricots
Ok, a couple of important discoveries. Both are leading me to believe it may be a grounding issue. Every time I've had bizarre problems it's come down to the fact that my Modcan modules are not grounded. So before I ask - How the hell do I ground them properly.

The dropped gates only happen when using my Klee. I do not however think there is anything wrong with the Klee. Even when a gate does not trigger, the LED blinks (the 60b gate LED does not turn on however). If I have only one gate going out to the 60b it works fine. As soon as I supply gate number 2 (which ever bus, it doesn't matter) it will start playing erratically.

The MD impulse trigger seem not to matter because I get the same results using a LFO as a clock source.

Could it be a grounding problem afterall? I've seen people put tinfoil on the rail beneath Modcan modules. Is this all I have to do to ground it?
sduck
How are you powering the modcan?
haricots
MOTM-900. The Klee is powered on a MOTM-950.
sduck
I just saw that other thread that you posted to - and yes, there may well be a ground issue.
drewtoothpaste
So is it pretty commonplace that people add additional grounds to Modcan modules?

My Miniwave acts weird (goes out of tune) if I don't have it patched to anything and it just occurred to me that this might be a grounding issue as well.
haricots
Help me understand. If I cover the rail which is common to all my Modcan modules in tinfoil, then solder a wire from one modules ground (I'm assuming there an unused ground hole somewhere to solder to) and attach the other end of the wire to a jack or the screw where the pcb attaches to the plate I should be ok?

Drew, my VCDO does the same thing. It's my only digital VCO and it is the only one that is never in tune when I turn everything on.
sandyb
haricots wrote:
Help me understand. If I cover the rail which is common to all my Modcan modules in tinfoil, then solder a wire from one modules ground (I'm assuming there an unused ground hole somewhere to solder to) and attach the other end of the wire to a jack or the screw where the pcb attaches to the plate I should be ok?

Drew, my VCDO does the same thing. It's my only digital VCO and it is the only one that is never in tune when I turn everything on.


i have my modcan modules on bridechamber rails. i've run a wire from the power supply ground point to one of the rails. i never really had any major issues not grounding the rails but doing this did sort out the odd time when something weird seemed to happen. usually this was when i was patching the modcan with my euro system.

edit: meant to say - conductive foil of some sort over wooden rails would do fine instead of metal rails.

sandy
haricots
very frustrating The main gate out on the Klee seems to be the only one that fires of gates properly with the 60b. For example if I have the main gate out to the 60b it works fine. If I plug in Gate 1,2 or 3 from the Klee to another gate input on the 60b 1,2 or 3 will not fire off consistently. Trigger out on the Klee fire of the gates properly on the 60b. Are the trigger outs 5v. hmmm.....

I'm starting to think that the 60b can't handle two or more 10v gate signals.

If I send gates from my MOTM-730 the 60b works fine.
theglyph
Do you have your Merge switches on?
drewtoothpaste
You know what? I was just messing around this morning and my VCDO does the same thing. If I don't patch a CV into it from another module, it flops around in pitch for no apparent reason. I'm gonna ground it when I get a chance and when I figure out where it should be connected to.
drewtoothpaste
I think the Modcan modules might expect the faceplates to be grounded and they're not in my wooden case - thus the reliable behavior once I patch them to another module and tie the faceplate to ground?
robotmakers
In my (very) mixed system of Moog, MOTM, Dotcom and (one) Modcan module, I've had considerable difficulty getting the Modcan Dual VCADSR to trigger with anything but the most "ideal" triggers. In fact, I'm in the midst of constructing a little amplifying opamp circuit to boost and buffer the gates generated by a particularly dodgy sequencer gating scheme I seem to have settled on. The fact that the Modcan envelopes have the "feature" of going high when nothing is plugged into the gate input MIGHT make them more sensitive to the output impedance of whatever is plugged into them, but that's just a guess.
haricots
drewtoothpaste wrote:
You know what? I was just messing around this morning and my VCDO does the same thing. If I don't patch a CV into it from another module, it flops around in pitch for no apparent reason. I'm gonna ground it when I get a chance and when I figure out where it should be connected to.


If and when I figure out how to do this I'll post it here. Last night I went through the bother of wrapping aluminum foil around the two rails that are common to my Modcan stuff. I was hoping (stupidly) that this would magically fix it ... but it didn't make difference. Tonight I might try soldering a wire from a modules ground and place the other end in between a face plate and the foil. Todd Fletcher suggest that I make sure I'm not overloading one of my power supplies (which I might very well be).
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