Sequencer doesn’t respond well to different clocks

[IvanS]

Bug description (state clearly and simply):
When the sequencer is clocked externally, it doesn’t follow the clock very well. I have tried it with Pamela Workout and Varigate8 clocks, the sequencer consistently skips steps.

Steps to reproduce (use numbered list):
Insert a sequencer, try clocking it externally and see how the pointer moves in the sequencer P page.

Software version (blank if unknown):
04092018

Type (major or minor):
Major

[bert]

can you post photos of your clock signals from the modules you mention? i want to make sure they go through 0v.

the clock input of the step sequencer only advances a step if the clock signal goes through 0 (rising edge).

[IvanS]

I will take pictures when I am home, but I think that if any other module that has clock input works with no issue, this has to be a SSP problem.

[IvanS]

Perhaps the clocking should be changed and be thresholded at say 1V. Again except bipolar LFO’s, no sequencer sends bipolar clock signals.

[bert]

I will take pictures when I am home, but I think that if any other module that has clock input works with no issue, this has to be a SSP problem.

not an ssp problem but just a difference in convention send me some details on the clock signals and we’ll go from there. changing the threshold should be doable.

[NeilParfitt]

I remember I had to adjust my Pamela’s Workout V1 Gate length slightly to behave with clocking a Z-DSP.

Could be the case here?

[IvanS]

The problem here is that the clock has to go through 0V to be detected. Instead there should be a threshold at 0.7V for example, or anything just above 0V. Bert said that this is so you can use bipolar lfo as a clock, but then you loose syncability with pretty much everything except that and you can’t sequence a sequencer as well. Hopefully this gets changed

[tiger001]

well, the sequencer doesn’t start/stop when slaved to MIDI clock as well (MIDI clock bug)
but this was an easy fix
but i noticed a lot of variation in the clock sync tempo when slaved (same thread)

[bert]

well, the sequencer doesn’t start/stop when slaved to MIDI clock as well (MIDI clock bug)
but this was an easy fix
but i noticed a lot of variation in the clock sync tempo when slaved (same thread)

the midi clock stuff is unrelated to the above issue @IvanS is talking about -

right now the clock input of the step sequencer requires the clock signal to go through 0V, the advantage with that is that you can feed it any signal without thinking about offset or amplitude, and it will work. what he wants is to move the threshold form 0V to maybe 0.7V or 1V such that if he feeds it a clock signal between 0V and 5V that it would work without any offsetting or scaling.

If we change the threshold, the consequence is that it now becomes amplitude sensitive, so you cannot use a signal between -0.5V … +0.5V for example as a clock signal. You will have to apply some gain to it.

I don’t think all of this is a big deal but I understand that it might save him some time in having to apply an offset/gain, so if no-one is against it we can move the threshold to 1V. Once that is done I cannot change it back again because we can’t go back and forward on a feature forever.

[IvanS]

So there are a few reasons why the “just above” 0V threshold will improve things:

1. Any clock generator, trigger/gate generator or anything that produces pulses in euro rack outputs these voltages from 0 to approximately 3V. So if you are trying to sync SSP to any of your clock generators or what not, it won’t work well because your clocks are not bipolar. The only thing you can sync SSP to is an LFO, which at times is cool but I doubt many people rely on an LFO for a clock if they have dedicated clock generators and sequencers or even midi gear.

2. The concert about the amplitude sensitivity, if you are trying to sync somthing to a clock or pulse or whatever, there is 99% chance this trigger is above 0.5V. The only scenario where the trigger or clock is below that level is if you put it through a VCA, which makes no sense. Since nothing in SSP is controlled by different amplitude of triggers I don’t see why you would ever have to modulate the level of a clock or trigger.

So to sum up, with 0V threshold you can only use a bipolar LFO to clock it and nothing else unless you offset it etc which i think is unnecessary. With 0.5V threshold you can use all of your clock generators or sequencers to clock SSP. Also with 0V threshold you can’t sequence another sequencer, because gate outputs on the sequnecer in SSP is unipolar.

[IvanS]

Also forgot to add, any eurorack module that has a clock input has a threshold, so having a threshold just above 0V is in a way a standard in eurorack.

[bert]

So if you are trying to sync SSP to any of your clock generators or what not, it won’t work well because your clocks are not bipolar.

it will work just fine but you have to offset your clock but I get your point, if no-one is against it i’ll move the threshold up.

[tiger001]

can we offset/scale with the INput module on the SSP?

[bert]

can we offset/scale with the INput module on the SSP?

yes of course, that has been in there for a long time now.

[IvanS]

Yes you can. I am just thinking that if there is a threshold for a trigger input on the sampler, then there should be a threshold for the clock inputs as well. Otherwise i don’t see why we should treat clocks and triggers as separate things.

[IvanS]

If clocks and trigger inputs are treated the same, that will improve compatibility of SSP modules betwwen each other. Fo example you can now use a gate output of one sequencer to clock another sequencer for interesting results. Then maybe in the future there will be logic modules that will be able to take 2 gate/trigger or gate/clock inputs and produce a variation based on the type of logic, you could then use this variation to clock another sequencer and so on. So i think people would miss out on the immediacy of use in areas where it is concidered a normal behaviour.

[IvanS]

Just last thing, in the case where your clock is let’s say below 0.5, this is not usual and hence is a special case. For such an occasion it is fine that you have to do extra work by scaling it and offsetting, but this won’t happen nearly as often as feeding triggers or gates into the clock input or using external modules as a clock source.