Yusynth Random Gates

[Funky40]

Hello Yves,

i gonna build the Random gates this Evening.
I have to build the Resistor Network with single Resistors.

Q: Can i just place the resistors vertical with one end soldered in,
and then wire them on the top end all together going to the common pin ( the one with a dot on the Network ) ?
Am i fine this way ?

[yusynth]

Yes this is correct.

[Funky40]

great , thanks Yves.
just drilled my Boards and faceplatelayout is a thing of 10 minutes i assume


just out of curiousity:
can i run the Random gate at audiospeed ?
I thought it migt be fun to use them as a kind of a Random clock divider to drive different seqeunzers


oh, and is it really random, or is it finally a kind of a Pattern ?

[yusynth]

[yusynth]

Hi

I have updated the circuit, I changed the values of R3 and R4 to higher values in order to have a higher input impedance for the clock input.

[Funky40]

Hello Yves,

i got today my ICs, so i finished my two Yusynth Random gates,
but both have the same Issue: ( the modification of R3 and R4 was done )
There is no shifting, only one LED is blinking with trigger switch to on,
and lighting when trigger switch is off.
The associated trigger out behaves the same as the LED

I see no boobs, all Bridges are in.
I tryed with boosting the clock input to be shure that it is not cause of to low level.
ahhh, one thing:
the trigger switch is not wired yet , but this should not affect anything i assume.
It's such a simple circuit.........
but i forgot to "piep" the unpopulated PCbs to check for any shorts from etching. From Eye it looked good.




any Ideas Yves ?

[yusynth]

Hi Funky40

Have you swapped the ICs between your two boards ?
Do you have a scope to check the signals ?

The behaviour you describe means that the clock in is working but the shift register doesn't shift.
Check that on pin3 of the 4006 you can see the clock signal.
With a scope check what's happening at pins 1,4,5 and 13 of the 4006 they level should change from 0V ro 15V at random rate. If not check that you have the right voltage on pin 14 of the 4006.
You should "pip" your tracks for this circuit remember what I wrote on my page

[Funky40]

report:


unit2 is working: the solution:
i patched now a pulse to the clock input instead of a Saw wave


But:
depending on which VCO i take,it has problems with the input trigger.
sometimes it jumps only between three outputs.( edit: this was this night )
patching no clock input and switching the momentary switch causes no jumping, it rests on the allways same step.( step 7)
It was also just standing on that step with slow clockspeed with motm VCO


edit: just right now it works well with the Motm VCO with slow Speed.
It seems that the module just needs some acclimatisation
with curetronic VCO ( pulse) it rests on step 7, no shifting.


i tryed now to compare the pulse from the Motm and curetronic VCO on the Scope.
I synced them in slow speed as good i could, inclouding sync patched.
Hard to tell..........i can't see any obvious thing why it is not working with the curetronic pulse.

( R3 and R4 are the new values as posted here from you )

..........................................................................


Random gate unit1 has a strange behave.
It might be something wrong with the module.
In short, because it might be from interest:

both modules don't shift when patching a saw. Unit2 works as soon i patch a pulse.
Unit 1 anyway just shifts between 3 steps, but now the funny thing:
if i bring it to rest on one ( allways the same) step, i can't bring it back to shift.
i must power down and up.
so there is something like a "locking" going on

................................................................

this circuit is definitly very sensible to what clock you feed.
It seems that you also detected something, regarding to your changing of R3 abnd R4

[yusynth]

Hi Funky40

The circuit was design to work with GATE signals that is clean PULSE signals with a positive plateau at +5V. It was not designed to be used with SAWTOOTH. If you look at the schematic you will see that the input circuit is a mere input buffer that inverts the input pulse. A SAWTOOTH won't work here because the input circuit has no schmitt triggers and therefore it expects a clean PULSE signal.
The fact you obtain different behaviour with MOTM and Curetronics means that there output pulse levels are different.

If you experience a different behaviour with the two boards, is this behaviour changed if you swap the ICs from board to another ? If the pseudo random sequence stops it is because an all 0 state has been detected. Normally the circuit is designed to avoid this (this the part of Q2). Did you use a BC547C...

The change of the values of R3 and R4 has nothing to do with this, it concerned only the impedance adaptation of the circuit.

It seems that if I have to redesign this module I would change the input circuit and use a schmitt trigger in order to accept all sort of clock signals.

[yusynth]

Hi again Funky

I gave some thoughts to your problem and also I had other returns from some people experiencing difficulties with this module.
It appeared that those other persons used different brands of the CD4006, in fact they were using HEF4006 or MC14006 which are given as equivalents of the CD4006.

I run some tests with my two built modules and I came to the conclusion that the circuit as is, works fine with true CD4006, but does not with HEF4006 and MC14006.

I checked the datasheet and noticed that these two late brands need a more stringent clock signal (in fact with a very steep falling edge).
Therefore I modified my circuit to improve the shape of the clock pulse and this is quite easy because I had two unused XOR gates in U3 (CD4070). I connected one of these gates with one input ( pin 13) connected to the collector of Q1 and the second input (pin 12) to ground, removed the strap between collector of Q1 and pin3 of U1 and then connected the output of the gate (pin 11 of U3) to pin 3 of U1.

And it solves all the troubles, it works perfectly now with both HEF4006 and MC14006. It works at high clock rates too !

I suggest you make that mod to your module and it should fix the problems you have.

I will propose very soon a corrected schematic and PCB on my site !

Cheers

[Funky40]

Indeed do i have the HEF4006.
I thought or hoped that it is something like this.
I'm just so unmotivated to debug modules, and still having quite some Backlog, so i never came back to your Random Gates.
( my racks are anywway full and half of what i built last year is liing around. Grande bordell ici )

Thanks very much Yves, i will do this modification and report back.





in the meantime i think it would be very useful to build the Module with muteswitches at each output, which i did not made

[Funky40]

just found a bag from Banzai,
originally labeled by Banzai with: CD4006

but they shipped HEF4006 ( must have been in the last 6 month )
Bridechamber ahs also the 4006 listed. maybe better to ask first

[yusynth]

Hi

here are the modifications to the PCB: removing a strap, cutting a track and connecting two wires.
With these mods, any 4006 can be used either CD4006 or HEF4006 or MC14006. I have not tested other brands than those mentioned before.

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[Funky40]

I did the modification now, but it is not running anymore. Only one LED is lighthing, no shifting with a patched clock (pulse/saw )

I just used the pins of the removed strap for the two wires.
one going to Pin13/U3, then back from Pin11 to where the strap goes (pin3/U1), plus the wire to ground from Pin12 of U3.
This is correct i think, can't see any faults.



ahhhh, you cut a track ?
it is from the drawing not clear to me which track.
edit: have not seen the second picture. I have also the wire to Ground from Pin12/U3, but still can't see the track to cut
edit2: i just recognised Pin12/U3 is allready to ground by default

[Funky40]

ahhh ok, you cut the track from Ground to Pin137U3. i try

[Funky40]

okydoky, the baby is kicking.
Very good feeling to debug respectivly modifie a module
thank you very much Yves.

gonna resolder the second unit now........and then i'm hungry. well, i'm allready


edit: ok, #2 is kicking too as it looks ( the LEDs are not yet sticked to the frontpanel)
two good reasons more to build the urgently needed new Cases.
thanks again Sir !

[yusynth]

Yep, it rocks

[Funky40]

I love it