ER-101 / Assimil8or - Voltage mismatch?

Mend · December 20, 2019, 11:34pm

Hi there,

For some reason my ER-101 seems to be acting up. I recently purchased the Assimil8or. The A8 lets you divide any sample - in this case a bassline - in up to 8 zones. Each zone can be attributed to a voltage so that my ER-101 can select, per step, which zone to play. Great for creating melodic sequences, interesting drumpatterns, etc.

But for some reason, when I set my zones ranging from:

zone 1 - 1.5v
zone 2 - 2v
zone 3 - 2.5v
zone 4 - 3v
zone 5 - 3.5v
zone 6 - 4v
zone 7 - 4.5v
zone 8 - 5v

It does not seem to select all zones. Rather, it repeats zone 1 twice and then moves on. Zone 8 is never selected. As you can see in this example: Click me

Oddly, when I set the voltage on a single step to below 1.5v, say for instance 0.5v it does select the step it normally won’t play. But that’s odd. Since I told my Assimil8or to range from 1.5v-5v.

I’ve asked Marco from Rossum over at Muffwigglers, but he seems to believe it’s an issue with the ER-101. Maybe not a bug, perhaps just a setting I glanced over. Can someone shed some light on this?

odevices · December 21, 2019, 6:20am

First, are you sure you took care of the CV vs Gate delay? This is often an issue when using CV/Gate to select something. The ER-101 gate is designed to follow the clock as closely as possible with minimal latency but CV might take a few more milliseconds to ramp up to the correct value.

Mend · December 21, 2019, 9:48am

I’ve played around with the Assimil8or’s delay settings a bit but found no improvement. Perhaps there is more that I can do to improve this but I’ve looked through the ER-101’s manual to see if anything came up with delay settings and correct me if I’m wrong, but I think in this case the A8 needs to compensate, and not ER-101, right?

Just thought it was worth mentioning that selecting a voltage below the selected zone-voltages of the A8 I am selecting a zone. Which shouldn’t be happening.

https://drive.google.com/file/d/1bV5kYAhmIl3_izn45QhnC0GEgxMQLrKQ/view?usp=sharing

As you can see it skips a zone. And when I dive below 1.5v it still selects a zone, when in theory it shouldn’t. It’s almost as if there’s some sort of offset going on somewhere.

odevices · December 21, 2019, 9:52am

I recommend as the next step is to directly measure the output voltage of the ER-101 with a voltmeter or if you don’t have one then try driving a VCO and see if it makes sense (e.g. the pitch doubles as you go from 0V to 1V to 2V to 3V and so on).

Mend · December 21, 2019, 12:13pm

https://drive.google.com/file/d/1bcRZP5NtkWkGyVhYfeq2d4RXNRh4lLLn/view?usp=sharing
That seems fine to me. Odd.

odevices · December 22, 2019, 12:01am

Was your test VCO in the same case as the Assimil8or?

Mend · December 22, 2019, 10:48am

Hmm no. I have two cases. You think that might be it?

Shapeshifter is in another case. Assimil8or and Er-101 in the one with issues.

odevices · December 23, 2019, 2:30am

I think it is a good idea to do your testing in one case for now. Successful debugging requires removing possible variables one-by-one.

Mend · December 23, 2019, 6:43pm

Good point. I’ve placed an osc in the same case and ran the same test: https://drive.google.com/file/d/1bpxfIK1Pt_iS4JNP0_4z9P1hdoEVyl8m/view?usp=sharing

Same result. The problem only seems to appear in the Assimil8or. I’ve also tried selecting the different zones with Planar2. And that works fine. I can select all zones. Hope that helps.

Mend · December 23, 2019, 8:05pm

Was just re-reading Marco’s reply at Muffwiggler from a while ago and I think I’ve got it now:

Here’s an example with 8 zones, from 0V to 5V:

1: +4.0V to +5.0V
2: +3.0V to +4.0V
3: +2.5V to +3.0V
4: +2.0V to +2.50V
5: +1.5V to +2.0V
6: +1.0V to +1.5V
7: +0.5V to +1.0V
8: -5V to +0.5V

Any voltage between -5V and +0.5V chooses zone 8 (so, in the case of the ER-101, that’s be any voltage between 0V to +0.5).

Just checked it and it appears the last zone is ranging from -5 to +0.5v, or 0 to 0.5v in case of ER-101.
I mean. He even says so. Must’ve misread it. Perhaps I got confused by the display. The little lines leading from the zones to their corresponding voltages can be a bit misleading. A bit hard to see which voltages they lead to.

Well. Anyway. Hope this reply helps anyone who’s running into the same issue