SEQ V4+ & Breakout Box - double trigger

Testing/Troubleshooting
1

hi all,

after testing i found an minor issue with my breakout-box. everything is working as intended but i get annoying double triggers on some modules. when i connect the same modules to my robokop sequencer or other trigger source everything is fine. could it be a grounding issue?

the +/-12V for the AOUT NG is coming from my eurorack and the +5V for AOUT NG and the LineDriver Receiver from an additional psu. the external psu (5v) is in the middle of the ribbon cable between AOUT NG and the receiver as suggested by latigid on. i also enabled the 1ms trigger but it makes no difference.

when using the same trigger on another module it works so i guess i can rule out the double trigger is coming from the sequencer itself.

please help

rbv2

2

Hola,

just tested the new dedicated midiphy eurorack modules, that are in the works - while i don’t have a big modular setup, i measured and tested gate and trigger outs and had no issues (tested triggering the “Freeze” and the “Trig” functions on a MI Clouds and also measured signal outputs with a scope). Therefore, I would also expect maybe a common ground problem on your side? Have you grounded the external PSU and the LineDriver Receiver to the modular/rack common ground?

The new euroceiver module (left in the pic below, which still uses handmade paper/epoxy panels for fit-testing) has a built-in voltage regulator, that allows generating the required 5v from the +12V modular rail, which will spare you the external psu and would not require you to send the +5v down the DB25 cable from the SEQ, which might be problematic.

Many greets and have a nice weekend!
Peter

 

3

hi peter,

thanks a lot for you answer.

8 hours ago, Hawkeye said:

Hola,

just tested the new dedicated midiphy eurorack modules, that are in the works - while i don’t have a big modular setup, i measured and tested gate and trigger outs and had no issues (tested triggering the “Freeze” and the “Trig” functions on a MI Clouds and also measured signal outputs with a scope). Therefore, I would also expect maybe a common ground problem on your side? Have you grounded the external PSU and the LineDriver Receiver to the modular/rack common ground?

at the moment i have wired 12V+/- and GND directly from a doepfer bus board to J3 of the AOUT NG the external psu is in the middle of the cable from JAOUT of the receiver to J1 of the AOUT NG. (Vs & Vd) . by common ground do you mean i should connect the Vs line of 5V PSU to the GND of J3 at the AOUT NG? all the jacks (gate, trigger, cv) are connected to ground and since the panel is made of aluminium the gnd of both psu’s is connected.

 

8 hours ago, Hawkeye said:

The new euroceiver module (left in the pic below, which still uses handmade paper/epoxy panels for fit-testing) has a built-in voltage regulator, that allows generating the required 5v from the +12V modular rail, which will spare you the external psu and would not require you to send the +5v down the DB25 cable from the SEQ, which might be problematic.

unfortunately i saw the information about the new modules too late. i would rather use them but i had already bought all the parts and ordered a panel at schaeffer..

i have also learned that the 5v on the doepfer boards are not there at all although it is written on it

 

thanks!

4

Probably can help you out way more than i can… but i just looked up the AOUT_NG schem and it seems analog ground can be tied to digital ground (see middle of the schem), maybe by a jumper? If that is the case, i think the grounds should be all tied down together and nothing is floating, which might cause problems. We are using the AOUT (not NG) module, so i don’t really know much about the NG.

Two more questions: do you use a DOUT module for the triggers? I think, if an analog out would be used for that digital purpose, the DAC might “overshoot” or ring or might not be quick enough, but that is wild speculation. Do you have access to a scope, so you can see the trigger output waveform?

Many greets and have a nice weekend!
Peter

5

hi peter,

at the shematic i can see the point you refering to but there is no jumper or place for a pinheader.

yes i use the DOUT module for 8x Gate, 16x Trigger an 8x Clock the AOUT NG is for CV only.

a friend of mine will lend me his scope. but i don’t have one right now.

 

thank you!

6

On 5/23/2019 at 6:22 PM, rbv2 said:

hi all,

after testing i found an minor issue with my breakout-box. everything is working as intended but i get annoying double triggers on some modules. when i connect the same modules to my robokop sequencer or other trigger source everything is fine. could it be a grounding issue?

the +/-12V for the AOUT NG is coming from my eurorack and the +5V for AOUT NG and the LineDriver Receiver from an additional psu. the external psu (5v) is in the middle of the ribbon cable between AOUT NG and the receiver as suggested by latigid on. i also enabled the 1ms trigger but it makes no difference.

when using the same trigger on another module it works so i guess i can rule out the double trigger is coming from the sequencer itself.

please help

rbv2

I repeat my advice from the other thread:

Could it be the HW config settings or an issue with midi loops feeding back in? More than one track assigned to AOUT? 

The perennial IDC cabling issue would also be worth checking. 

 

You could also test with _NG again and in MIOS terminal

set dout x 1

to check if the problem is replicated. For x you have to count the number of shift register outputss in the chain, starting from 0-7 for the first one. Or simply replace x with ‘all’.

 

21 hours ago, Hawkeye said:

Therefore, I would also expect maybe a common ground problem on your side? Have you grounded the external PSU and the LineDriver Receiver to the modular/rack common ground?
 

Check the resistance of your 0V from the Eurorack to somewhere on the SEQ e.g. pin 2 on a MIDI out (the one at 6 o’clock).

In the line receiver, is jumper J3 closed? This could cause interference on the +5V line if there are two PSUs fighting.

 

12 hours ago, rbv2 said:

at the moment i have wired 12V+/- and GND directly from a doepfer bus board to J3 of the AOUT NG the external psu is in the middle of the cable from JAOUT of the receiver to J1 of the AOUT NG. (Vs & Vd) . by common ground do you mean i should connect the Vs line of 5V PSU to the GND of J3 at the AOUT NG? all the jacks (gate, trigger, cv) are connected to ground and since the panel is made of aluminium the gnd of both psu’s is connected.

If you use an external PSU you must connect the 0V together with the +/-12V PSU 0V common line. A metal panel is not a good (and some would say unsafe) method of achieving common 0V.

 

12 hours ago, rbv2 said:

i have also learned that the 5v on the doepfer boards are not there at all although it is written on it

I guess you are not using the +5V on the bussboard? But if you are, maybe you don’t have +5V connected and the modules are being parasitically powered from the digital signals? (This is not good for CMOS btw.) Did you measure correct +5V on the modules?

 

9 hours ago, Hawkeye said:

Probably can help you out way more than i can… but i just looked up the AOUT_NG schem and it seems analog ground can be tied to digital ground (see middle of the schem), maybe by a jumper? If that is the case, i think the grounds should be all tied down together and nothing is floating, which might cause problems. We are using the AOUT (not NG) module, so i don’t really know much about the NG.

There is only one “ground” and the separation of analogue/digital 0V is a complex and often misunderstood topic. On AOUT_NG the two are connected underneath the DAC chip; there is no jumper etc.

 

9 hours ago, rbv2 said:

a friend of mine will lend me his scope. but i don’t have one right now.

A scope might be useful to see what’s going on.

7

hi latigid on,

thanks a lot for your answer.

 

  • since i have made no changes in the HW Config beside setting the 1ms-option and SRs for clocks, gates & Trigger i would assume no

  • all tracks muted except for the one sending triggers to CH16

  • checked all cables visually again

  • the resistance between 0V Eurorack and pin 2 of a Midi Socket oscillates between 1,8-2,5 Ohm

  • no jumper in J3

  • the double trigger only occours on some modules and depends on the setting of the length in the parameter layer, when length is 4% it’s almost gone, it’s acting like a gate..

  • I’ll try to do the tests in mios when I understand how it works 

7 hours ago, latigid on said:

If you use an external PSU you must connect the 0V together with the +/-12V PSU 0V common line. A metal panel is not a good (and some would say unsafe) method of achieving common 0V.

so the connection underneath the DAC is not sufficient then?

7 hours ago, latigid on said:

I guess you are not using the +5V on the bussboard? But if you are, maybe you don’t have +5V connected and the modules are being parasitically powered from the digital signals? (This is not good for CMOS btw.) Did you measure correct +5V on the modules?

yes, i am using an external power plug. i get 4,96V on J2 of AOUT NG and 4,96V on J19 of the Receiver

unfortunately I still have to wait for the scope..

 

thanks

rbv2

 

8

Everything sounds correct.

 

7 hours ago, rbv2 said:

so the connection underneath the DAC is not sufficient then?

Yes and no? Try to have the 0V common to both PSUs, i.e. at the source of the power.

9

thanks!

to be on the safe side, I made a drawing.

it shows my current wiring. the black line with the question mark shows how I understand it.

would that be okay?

thank you!

rbv2

cgnd.jpg.1725882b25595559d263e627dfbbd4f2.jpg
cgnd.jpg.1725882b25595559d263e627dfbbd4f2.jpg1239×1754 84.9 KB

 

 

10

Is the external PSU actually +5/-5V? So a 10V supply?

The 0V should be common rather than 0V to -12V. I think that’s what your diagram shows, but the 0V of the PSU should connect to the yellowish wire on your diagram, not the black -12V

11

5 minutes ago, latigid on said:

Is the external PSU actually +5/-5V? So a 10V supply?

no, its 5V didn’t know how write it correctly.

 

8 minutes ago, latigid on said:

The 0V should be common rather than 0V to -12V. I think that’s what your diagram shows, but the 0V of the PSU should connect to the yellowish wire on your diagram, not the black -12V

yes, isn’t so well drawn but that’s what I meant.

 

thanks. i try it and report

12

thanks a lot, it’s working much better now also the random triggers when inserting cables are gone now :slight_smile:

only get double triggers on very long “lenght” settings wich i assume is normal behavior. are those real triggers or very short gates?

thanks and for your support and patience
you deserve a beer

btw. where is the “buy hawkeye a beer” button?

13

Cheers! 

I’m not 100% sure what you mean with very long lengths. Does it remain when the gate length is set to glide? Video?

14

2 hours ago, latigid on said:

I’m not 100% sure what you mean with very long lengths. Does it remain when the gate length is set to glide? Video?

when sending out triggers from AOUT Ch16 and then select in the parameter layer “lenght” i can change the lenght of the trigger/gate from 1% to Glide

at 1% - no trigger

at 2% - sporadic trigger

from - 3-20% steady trigger

from - 21-100 % double trigger with increasing distance (21% narrow / 100% wide)

glide - only the first trigger

before we fixed the grounding issue i got double triggers starting at 5% and other problems but now i’m pretty shure those are gates and not triggers making some modules being triggered at the beginning and the end of that rectangular pulse.