Marbles x1 and x3 voltages out of synch with t1 and t3 gates?

My Mutable Instruments (not a clone) Marbles appears to be acting strangely. If I understand correctly, the voltage at x1, x2 and x3 should always change in synch with the corresponding t gates and loop with a pattern corresponding to the Length parameter when Déjà Vu is enabled. With my unit, this is always the case with t2 and x2. However there appears to be some slippage or something with the t1/x1 and t3/x3 relationships. This “slippage” or whatever we want to call it is most likely to occur when the gates are irregular (like when they sound like a swing beat). For example, at a length of 3, Marbles will sometimes create a pattern that sounds like it has six repeating elements. Also, the higher the Length setting, the more likely this behaviour is to occur. It appears to always happen at lengths 12 and above and often with 8, less so with 6 and 3. I don’t think it ever happens with 2 or 1. I could be wrong (I have driven myself a bit mad trying to perceive the pattern at higher length values), but it appears the pattern in these scenarios does repeat, but it does so at a multiple of the Length value (or some other non-relating number) as if there is some regular slippage between corresponding t and x outputs. Is there something wrong with my module or is this normal behaviour?

To rule out any parameters causing this behaviour, t and x are locked (green lights), Déjà Vu is at 12 o’clock, I’m in the green Y setting, Jitter is fully CCW and nothing is being modulated.

When something is wrong with a digital module, it’s never in a subtle way like this. What kind of defect could cause the module to behave normally except for this little thing?

I think you are misunderstanding what LENGTH adjusts. From the manual:

  • When the X section is not externally clocked, X1, X2 and X3 are rhythmically independent from each other, each output changing its voltage at its own pace. Setting the loop LENGTH to 3 (for example), will cause each output to go through a 3-note sequence independently from the other, creating polyrhythmic effects.

To paraphrase this, setting the loop length to 3 does not mean that you will create a looping 3-beat pattern. It means that each “decision” (internally, sampling a value from the internal random source) will cycle over 3 values.

Let’s take an example… If the t section is in green mode a “decision” is taken at each pulse of the clock, and is used to select between t1 and t3. So if they repeat with a length of 3, you could get a pattern like this:

t1: x--x--x--x--x--x--
t3: -xx-xx-xx-xx-xx-xx

X1 will pick a voltage at each pulse of t1, and will repeat these decisions (A, F, G in the example below) with a cycle length of 3. X3 will pick a voltage at each pulse of t3, and will repeat the same 3 decisions (C, F, E in the example below). This will result in the following pattern:

t1: A--F--G--A--F--G--
t3: -CF-EC-FE-CF-EC-FE

As you can see, it does not loop over 3 beats, it loops over 9.

If you want a more structured “global” loop length of 3, you can self-patch t2 to the clock input of the X section. Then all the X outputs will all change at the same “master” rate:

t1: AFGAFGAFG
t3: CFECFECFE

And you can use an external S&H on t1/X1 and t3/X3 to hold the voltages:

t1: A--A--A--
t3: -FE-FE-FE
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Ah, I see! Thank you for the clear explanation and example; I will enjoy working with the module so much more now that I understand this.