positive and negative gates

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pristak
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positive and negative gates

Post by pristak » Tue Feb 10, 2009 9:16 am

I have a Mobius and it has a switch on it for positive and negative gates.

Using Doepfer ADSR's instead of leaving the gate on the Mobius positive I switched it to negative one day. And where the rhythm had been a bit straight and almost boring, it suddenly had a swing and a groove to it.

I think the Doepfer expects a positive gate. So, what would account for this?

This is probably a simple observation and question, but I'm bored at work and these are things I ponder when I should be doing something else.

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futuresoundsystems
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Post by futuresoundsystems » Tue Feb 10, 2009 1:38 pm

Could it be that the envelope is now triggering half a step off as the negative gate goes back up to 0V? I don't know why the ADSR would detect that, unless the gate signal rests at just above 0V.
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pristak
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Post by pristak » Tue Feb 10, 2009 1:53 pm

I'll put the meter between the mobius and the adsr tonight and see.

I am perplexed because I had thought it would just not fire the adsr if the gate was the wrong polarity, but I was wrong. So so pleasently wrong.

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Post by b3nsf » Tue Feb 10, 2009 2:23 pm

is S-trigger a neg gate? one of my sequencers is not triggering with positive triggers, perhaps its the "S" :doh:
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Reese P. Dubin
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Post by Reese P. Dubin » Tue Feb 10, 2009 3:36 pm

I did this for years with my 808 triggering an MG1 which was looking for S trigs or negative gates or whatever. My silly understanding was that it was taking the falling side of the pulse just the same as it would a negative pulse.

It makes for a nice swing effect.

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Post by wetterberg » Mon Feb 16, 2009 11:11 am

If the env is expecting to trigger on *rise*, it'll be the "rear end" of a to-negative gate. So yes, in that case the length of the gate == length of a gate delay in relation to the envelope.

.... uhm, I hope that makes sense, at least?

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brandon daniel
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Post by brandon daniel » Mon Feb 16, 2009 5:15 pm

S trig is the logical inverse of gate, IE, high is 0V and low is +V, this is, obviously, different from a "negative gate", which I would assume would mean high is -V and low is 0V.

If an S-trig signal is plugged into a device expecting a normal gate, or vice versa, the end result is that the device will trigger on the "rear edge" of the gate signal being sent to it and remain on until the next gate is sent.

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