[sdiy] How long should a Trigger pulse be?

[Olivier Gillet]

Two data points I got from users having problems with my products:
* Doepfer Dark Energy does not retrigger correctly if the gate goes
from +5V to 0V back to +5V in less than 0.5ms.
* Doepfer CV to MIDI interface occasionally misses 1ms triggers.

Olivier

On Wed, Dec 18, 2013 at 7:47 PM, MTG <grant at musictechnologiesgroup.com> wrote:
> My only experience is with the Sequential Pro One and I'm using 1
> millisecond there.
>
> GB
>
>
> On 12/18/2013 6:47 AM, Tom Wiltshire wrote:
>>
>> Here's the timing for that little circuit, BTW:
>>
>> http://www.electricdruid.net/GateAndTriggerTiming.png
>>
>> On 18 Dec 2013, at 14:38, Tom Wiltshire <tom at electricdruid.net> wrote:
>>
>>> Hi All,
>>>
>>> I'd like the benefit of your combined experience, if I may.
>>>
>>> I'm decoding MIDI Note On/Offs and outputting Gate and Trigger pulses to
>>> drive envelopes. My own envelope designs don't need a very long trigger
>>> pulse in order to fire, but I thought perhaps some others do.
>>>
>>> Currently I'm using 500us Triggers, but I don't have a big pile of old
>>> synths here to try that on, so I don't know how well that will work on
>>> vintage gear.
>>>
>>> And then of course, there's the problem of envelopes or synths that don't
>>> have a Trigger input...
>>> I remember the Kenton Pro-2 MIDI-to-CV convertor had a "retrigger" mode
>>> where it dropped the Gate briefly to allow Gate-only envelopes or synths to
>>> retrigger. It didn't say how long it dropped the gate for though. I'd
>>> thought to do something similar with the following circuit:
>>>
>>> http://www.electricdruid.net/GateAndTriggerCircuit.png
>>>
>>> This converts Gate and Trigger into a Gate-with-gaps that will retrigger
>>> a Gate-only envelope. And this is the main reason for my asking the
>>> question; In this case, the output gate is essentially delayed by the length
>>> of the trigger pulse, hence my desire to keep it as short as possible. If it
>>> wasn't for that, I'd just use 5ms and reckon that'd trigger anything.
>>>
>>> So, oh wise ones of Synth DIY, how short can my trigger pulse be?
>>>
>>> Thanks,
>>> Tom
>>>
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>>
>>
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