Synchronization Question
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Author:  Kyhotay [ Thu Apr 12, 2012 8:06 pm ]
Post subject:  Synchronization Question

Heya Scott,

I wanted to ask if there is a proper way to interface the 6770 Master Synchronizer with the 4870 Sequencer. I tried several settings until I found one that mostly worked:

I run a patch cord from the 6770 to whatever Gate/Note Value I want to the 4780's sync in jack. The stop/run switch is set to stop and the tempo control on the 4780 is advanced CW.

I am running an 8 event sequence. I have the pin jack from stage 8 going to a patch panel and am "passively" mixing it with the 6770's "run" output. The patch panel out is going to the "load" jack so when I set the 6770 to run, it both starts and "loads" the sequence.

This works fine for the most part since the sequence now follows the Int Tempo pot on the 6770 and whatever "note value" I am patching to the sync input. The problem is that each time I start the 6770 the sequence starts from the 8th stage. not the first stage. Even if I clear the counter by running the stop/run switch up and down the sequence always starts from stage 8.

How do I get the sequence to start from the first stage of the Sequencer?

Thanks in advance for your sage advice,

Brian Folkes

Author:  PAiA-Scott [ Fri Apr 13, 2012 2:19 pm ]
Post subject:  Re: Synchronization Question

Hello Brian.

I wonder if it might be the passive mix of the final output stage and the Run/Stop. Run is always high when the MS is clocking the sequencer, but the final output is only high for this stage's duration.

If disconnecting the passive mix and only sending the final stage back to the Load corrects things, then the mixing or combination of low and high logic levels is resulting in a conflict and is the cause of the trouble.

A special patch cord or patch area could be made using diodes and a resistor to provide an OR function for the two levels working to Load the sequencer.
The diodes "point" in to the Load input with a resistor to hold the other end "low" tying joined ends of the diodes to ground.

OR_edited.jpg [ 49.07 KiB | Viewed 18688 times ]

Now the positive going Run OR Final-Stage Output can go forward through the diode into the Load input, but not back into each other.

Author:  Kyhotay [ Fri Apr 13, 2012 3:28 pm ]
Post subject:  Re: Synchronization Question

That makes sense. I was checking the outputs of both the run and reset levels and, like you said, the run is high till reset. And, yes, when I run the 8th stage into load and press the load button it works fine.

I need to go to RS over the weekend for the diodes and rig up a set of temp patch cords. If this works I might want to set up part of a patch panel instead of cords. How would I wire that up? I'm lousy with schematics. I need step by step instructions or at least draw me a picture!

Have a great week end!


Author:  Kyhotay [ Fri Apr 13, 2012 4:28 pm ]
Post subject:  Re: Synchronization Question

While I'm asking about it, how would you connect 2 sequencers to run a parallel sequence? Series sequence? 3 sequencers?? I tried to do a 24 step sequence following the using manual but I guess it didn't anticipate a clock coming from another source.

Would driving the 4780 from MIDI>CV be any easier?


Author:  Kyhotay [ Sun Apr 15, 2012 8:12 pm ]
Post subject:  Re: Synchronization Question

I am not sure if I hooked the patch cable right. I did a temp one to see if it worked. I ran cable from the MS Run out, connected the 1N914. Used the 8th step out and connected the other diode to it. I twisted the leads together, along with the 470 kOhm Y-V-Y, right? From the junction I went to the Load input and the other end of the resistor to system ground from one of the patch panels.

4780 was st to Stop and I threw the "go" switch on the MS and...nothing. I hit the load button and it played (through all 12 events) but would follow the tempo of the MS.

Any idea what I did wrong? Is there a better way to make a temp cable?


Author:  PAiA-Scott [ Tue Apr 17, 2012 10:09 am ]
Post subject:  Re: Synchronization Question

The banded (cathode) ends of the diodes are towards the Load input, right? Yes, the 470K resistor color code is yellow-violet-yellow-gold.
It works to hold the diode junction with the Load input at zero when there isn't a Run or Sequencer-Stage-Output voltage level to make it positive voltage.

The series or cascaded sequencer patch has them tied to an external clock or the output the first one over to the second one.
The final stage output of the first one goes to the load input of the second one and its final stage back to the first one for a loop.
If using the first one as the clock for the second one, try using the gate-trigger as the clocking pulse to the second's Sync input.

Author:  Kyhotay [ Tue Apr 17, 2012 10:43 am ]
Post subject:  Re: Synchronization Question

I think that's what I did. The "non-banded" end connects to the run and final stage cables, right? I formed a junction at that point and ran a cord to the load jack with the system counter cleared. The other end of the resistor went to a ground point on a patch panel.

Would it work better if I took a patch panel and - from left to right - soldered a diode (non- banded end) to pin 1 and attached to pin 3 (for Run). Then soldered a diode to pin 2 (non-banded) for the final stage input and connected the banded end to pin 3. Attach the resistor to pin 3 and solder all three wires. Connect the other end of the resistor to system ground or audio jack ground.

Whadda ya think?



Author:  PAiA-Scott [ Mon Apr 23, 2012 10:29 am ]
Post subject:  Re: Synchronization Question

Are you using the MIDI2CV8 for the timing clock available in operating mode six? If so, use the reset pulse instead of the Master Synchronizer's Run/Stop signal. I think the toggle action of the Run/Stop signal might and it always being positive for the run condition might keep the Sequencer's final-stage-output from operating the Load input through the added OR 'patch'. The mode six Reset pulse would just go positive as a pulse, the instant the Run condition is activated. Otherwise, a capacitor and maybe diodes and resistors would need to be added to make the Run/Stop toggle a pulse.

Author:  Kyhotay [ Mon Apr 23, 2012 3:22 pm ]
Post subject:  Re: Synchronization Question

No I have set the MIDI>CV to setup 6 unit. How do you start and stop the MS? With a note on from the sequencer track (Sonar)?


Author:  PAiA-Scott [ Sat Mar 05, 2016 8:58 am ]
Post subject:  Re: Synchronization Question

...nothing like having a devices set-up and operating for experimenting... I set up a TR909 as the MIDI Input to a 9700 MIDI2CV8 in the DIN Sync mode as a source for control signals to a 4780 Sequencer module.

OK, it's simple. As is recommended for external sync clock, set the 4780 Run/Stop to Stop and advance the internal clock's Rate control fully CW.

Rather than using the Run/Stop, use the Start or Reset pulse from MIDI2CV8 as the Run input on the 4780.

Since the 4780 Sync (external clock pulse) input is direct (as opposed to MIDI or DIN 24 pulse per quarter note), the '909 served as a source of quarter-note (or whatever interval) pulses for input to the 4780 synch connector.

Voila. The sequencer starts when the start button is pressed and it clocks with the external event pulse.

When necessary to start it all again, the 4780's Run/Stop switch must be manually actuated so the return to the Stop setting clears all the stages -- the next remote start/clocking will load and begin from the 4780's first stage.

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