noise cornucopia random gates

[johnnymad]

i read all the other threads where people were having issues with the random gates on the noise cornucopia. i finished building my yesterday. at first no gates were being produced. i changed transistors and fixed the problem...i think. the led blinks and it produces gates, but it doesn't really go that fast. it's not slow either, it just doesn't speed up until the led is constantly on. is this normal, or should i try another transistor??

[Etaoin]

After trying several transistors I ended up changing R8, as Ray suggests in his notes, to get it to output within the +/-5V range.

[johnnymad]

[fluxmonkey]

which pin on the 4024 divider chip did you choose? pin 12 is the divide-by-2 output, which should provide the greatest number of triggers. i put a rotary seletor switch so i could change divisions on the fly.

bbob

[johnnymad]

i think i used pin 5, as ray did. it's too late to add a rotary to my panel, but i'll clip the jumper and try pin 12.

[fluxmonkey]

yeah, so that should help (x16, in theory)...

pin 12: divide-by-2
pin 11: divide-by-4
pin 9: divide-by-8
pin 6: divide-by-16
pin 5: divide-by-32
pin 4: divide-by-64
pin 3: divide-by-128

[johnnymad]

i really wish i had room for a rotary. that's a really cool idea. maybe i can squeeze one in or at least add a spdt or so i can use more than one output.

[Captain Biscuits]

Oh I do love this forum.

Finished my Cornucopia last night and it seemed fine except for the random gates.

Quick search and problem solved. R8 needed to be nearer to 100K than 270K.

I did use a spare 12 way switch to try all the randomness options too and it seems a crime not to find space for it on the panel as it's all wired up and working so I have one more knob to twiddle.

Many thanks to all the posters, questioners and modulators who've provided such a useful searchable resource to solve all my problems late at night when a stubborn module is stopping me from sleeping.

Cheers

Ian

[diablojoy]

snap same deal. I just finished a dual module and that is such a good idea now i will have to find some panel space for 2 rotary switches it seems.
100k for R8 will have to try that also to see if it improves the pulse as i'am having trouble with some modules not seeing them. thanks

[sonicwarrior]

[sonicwarrior]

Used the /2 (fast), /16 (center) and /128 (slow) positions now.
I don't think a full rotary switch is needed as the frequency ranges by the frequency knob overlab with these settings already. So I would suggest to save the front panel space and use an on-on-on switch with these positions instead.