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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
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Posted: Mon Jul 23, 2012 3:48 am Post subject:
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all i could think of by now is a propagation delay issue (however, noone reported this behaviour before): the gate is still open when the new clock trigger comes in.
try to leave off the GATE conditioner IC5B, IC5C. does this help?
i will check my builds tonight (hopefully). _________________
cheers,
matthias
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fonitronik at
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
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Posted: Mon Jul 23, 2012 2:53 pm Post subject:
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fonik wrote: | i will check my builds tonight (hopefully). |
so i did.
and in fact i too see this very short pulse. i almost got rid of it by moving the two inverts from the gates path to the clock path. i then had 4 inverters in the clock path to add some propagation delay. at very high speeds i still see the 2nd very short pulse.
i think even without this mod i never recognized the 2nd short pulse just because the subsequent modules i used did not react...
so thanks for your finding. i will look deeper into it the next days. tonight i am done, hehe. i did the mod on a SMT board by desoldering the appropriate pins of the 40106, bending them up, and connecting them by flying wires! has been a little bit fiddly... will be easier on a socketed DIP. _________________
cheers,
matthias
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fonitronik at
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billy pilgrim
Joined: Feb 12, 2008 Posts: 36 Location: nyc
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Posted: Mon Jul 23, 2012 8:25 pm Post subject:
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Matthias,
Thanks for looking into this, I too thought that some kind off timing offset might be effective but had no idea how to implement it. If you find a solution I'll be keen to try it, thankfully no SMT for me.
FWIW the short "end" pulse reliably triggers my 281 clone at any speed.
billy
Quote: | and in fact i too see this very short pulse. i almost got rid of it by moving the two inverts from the gates path to the clock path. i then had 4 inverters in the clock path to add some propagation delay. at very high speeds i still see the 2nd very short pulse.
i think even without this mod i never recognized the 2nd short pulse just because the subsequent modules i used did not react...
so thanks for your finding. i will look deeper into it the next days. tonight i am done, hehe. i did the mod on a SMT board by desoldering the appropriate pins of the 40106, bending them up, and connecting them by flying wires! has been a little bit fiddly... will be easier on a socketed DIP. |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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Posted: Tue Jul 24, 2012 12:54 am Post subject:
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i just did a quick spice simulation during my morning brake using a RC delay: i put a 10 resistor followed by a 100n cap to GND between two of the inverters.
makes a nice delay, however, i don't know about the exact maths. according RC time constant we would get 1/1000 sec... anyways, you see the problem here: the delay is constant while the speed of the sequencer changes. we will have to find a good compromise, i guess.
i hope to find some time this week to implement this on one of my sequencers, and to find good values. _________________
cheers,
matthias
____________
fonitronik at
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diablojoy

Joined: Sep 07, 2008 Posts: 805 Location: melbourne australia
Audio files: 11
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Posted: Tue Jul 24, 2012 10:15 pm Post subject:
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Matthias I think this looks like the issue i came across a while back scott stites has a good example of the behaviour on his
matrix sequencer page that he is working on, it seems it is inherent to the 4017 operation which overlaps its outputs
if it is the same problem i did a little slew daughter board a while ago to get round it for the sequential switch part on that ludicrous symple64 build of mine.
I will dig up the details when i get home tonight and see if it can be incorporated somehow from memory the slew delayed the leading edge of the clock by around 150usec
cheers
Denis _________________ In an infinite universe one might very well
ask where the hell am I
oh yeah thats right the land of OZ
as good an answer as any |
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diablojoy

Joined: Sep 07, 2008 Posts: 805 Location: melbourne australia
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Posted: Wed Jul 25, 2012 1:48 am Post subject:
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Quote: | i think even without this mod i never recognized the 2nd short pulse just because the subsequent modules i used did not react... |
yes the second pulse is very short around 50+ usec's
this is the overlap of the 4017 outputs where output 2 goes high before output 1 goes low and so on for each output used
find attached how i got around this on the sequential switch circuit i mentioned, it was very neccesary in that case as i was switching clock signals though not so much generally with a straight sequencer as most EG's will not react to such a short pulse or so i thought it seems
It hasn't been an issue with my VCPS-8 so far
On the VCPS-8 the attached circuit would need to go between IC6 pin 14
and IC5 pin 11 , there is a small via between IC11 and C18 that would make a good point to solder a wire to from the output of the daughter board and you would need to cut the trace heading back to IC6.
this should have the effect of shortening the start of the clock pulse that is anded with the gate pulse till after the previous step output has released.
For the input to the daughter board i think you could get away with just running another wire from the clock in jack. edit : hmm better maybe to kludge a wire off D21/D22 cathode end instead.
the attached circuit adds a glide to the leading edge only of the pulse
so it is a little better than a simple RC circuit, admittedly it is also quite somewhat more complex. and i have not tested it with a VCPS-8 but it has been tested with a 4017 based sequential switch
If you go ahead and decide to try this the foil attachment should simply be printed straight onto pnp blue just check the scale is correct first though it should be correct.
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seq switch clock adaptor.pdf |
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seq switch clock adaptor foil.pdf |
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_________________ In an infinite universe one might very well
ask where the hell am I
oh yeah thats right the land of OZ
as good an answer as any |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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Posted: Wed Jul 25, 2012 3:42 am Post subject:
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okay, i just tested it during the lunch brake. my simple clock delay circuit works like a charm. i ended up with the trimmer set at about 9k, so 10k should still be working nicely.
SO ALL WHO EXPERIENCE PROBLEMS WITH A 2ND (GATE OFF) TRIGGER GENERATED
refering to sketch in post above:
1) bend up pins 10 & 13 of IC5 (the 40106 hex inverting schmitt trigger) - hopefully you have them socketed.
2) solder a 10k resistor between these pins (right on top of the IC).
3) solder a 100n cap from pin13 IC5 to GND (i.e. at the decoupling cap). _________________
cheers,
matthias
____________
fonitronik at
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billy pilgrim
Joined: Feb 12, 2008 Posts: 36 Location: nyc
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Posted: Wed Jul 25, 2012 8:57 pm Post subject:
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Mod works really well, though I had to use 200n. It's a great module..........
fonik wrote: | okay, i just tested it during the lunch brake. my simple clock delay circuit works like a charm. i ended up with the trimmer set at about 9k, so 10k should still be working nicely.
SO ALL WHO EXPERIENCE PROBLEMS WITH A 2ND (GATE OFF) TRIGGER GENERATED
refering to sketch in post above:
1) bend up pins 10 & 13 of IC5 (the 40106 hex inverting schmitt trigger) - hopefully you have them socketed.
2) solder a 10k resistor between these pins (right on top of the IC).
3) solder a 100n cap from pin13 IC5 to GND (i.e. at the decoupling cap). |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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Posted: Wed Jul 25, 2012 11:12 pm Post subject:
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billy pilgrim wrote: | Mod works really well, though I had to use 200n. |
yep. for a 2nd module i had to go up to 33k. maybe a trimmer instead of a fixed resistor would be the way to go? _________________
cheers,
matthias
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fonitronik at
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brother303

Joined: Nov 02, 2010 Posts: 139 Location: ruhr-area/germany
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Posted: Sat Sep 01, 2012 4:49 am Post subject:
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Hi Fonik,
do you still have pcbs on stock? I´d like to purchase another one.
Cheers
Greg
 _________________ Best regards
Greg |
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blynkmusic
Joined: Jun 07, 2013 Posts: 1 Location: UK
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Posted: Fri Jun 07, 2013 2:42 am Post subject:
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Are you still making these units? I would love a ready made rack unit if you have any left over?
Thanks,
Sam |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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bamboombaps
Joined: Oct 23, 2015 Posts: 60 Location: Glasgow
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Posted: Wed Jan 13, 2016 6:22 am Post subject:
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will this ever get another run? *realises thread is older than my children* |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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Posted: Tue Jan 26, 2016 1:57 am Post subject:
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meanwhile the sequencer is available as eurorack module via schneidersladen and analoguehaven. however, you could buy a module directly from me.
anyways, i am planning to do a new version with front panel adapter PCBs for 4U/Serge and Eurorack. no schefude yet. _________________
cheers,
matthias
____________
fonitronik at
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bamboombaps
Joined: Oct 23, 2015 Posts: 60 Location: Glasgow
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Posted: Tue Jan 26, 2016 2:08 am Post subject:
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I've actually got a pcb coming in a trade but ill need a panel if there's any kicking around |
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bamboombaps
Joined: Oct 23, 2015 Posts: 60 Location: Glasgow
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Posted: Tue Feb 16, 2016 8:58 am Post subject:
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or even if theres a .fpd file for euro? |
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fonik

Joined: Jun 07, 2006 Posts: 3908 Location: Germany
Audio files: 23
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bamboombaps
Joined: Oct 23, 2015 Posts: 60 Location: Glasgow
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Posted: Thu Feb 25, 2016 6:21 am Post subject:
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yep this was before i emailed you
thanks again matthias  |
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