a nice RNG mod

[birt]

a nice mod for those who built the random number generator



make the 100K feedback resistor 50K and put a diode between the collectors of the second and the third transistor, kathode to the second transistor.

it makes it a lot more usable for me, the sounds are jumping all over the place (like they should) but the notes are more defined and there is a lot less gating. It has also more harmonics on the lower notes i think. since it is not gating as the original you get more noise when you are not playing but it's a noisebox right? :p


Have fun!

[jrc4558]

Hey birt! Thanks for the idea!
Is that instead of the capacitor or before the capacitor?

[birt]

Kathode to the point where both 470K resistors and collector are connected, anode to point where both 100K res and collector are connected.


with this mod i'm gonna keep the RNG instead of reusing the parts. it sounds a lot different than the stock version.

also play around with transistor gains. i used about 50hfe for the first 3 and 200 for the last one. if i switch the first and the last one the sound changes too.

[ambulancevoice]

better yet, why not do the feedback pot mod

so like this maybe

[birt]

because i didn't like that mod :p
i only liked the 50K setting so i kept it there

[DWBH]

Hey guys, just one question. What does a Random Number Generator do? Does it sound like Maths?

[oldrocker]

From the description I was picturing the diode like this.  I just want to make sure.

[ambulancevoice]

yeah thats probably right
i just chucked mine together quick like

[smnm]

Hey guys, just one question. What does a Random Number Generator do? Does it sound like Maths?

http://www.diystompboxes.com/smfforum/index.php?topic=56638.0

[ambulancevoice]

Hey guys, just one question. What does a Random Number Generator do? Does it sound like Maths?

its a random arpeggiating fuzz pedal, it randomly adds - octave to the signal with alot of fuzz dist stuff

for noise freaks reallys

[birt]

the drawing is correct.

[oldrocker]

I'm not sure now. Which is the correct drawing?

[oldrocker]

Well I did add the diode and it sounds better.  There's more control over the effect and it's still as outrageous as always.  Overall a good mod.  Thanks.

[birt]

i meant the second one

which one did you try? :p

[danceatron]

This is a good pedal to use sockets the transistors. If you have a good variety on hand, you can get lots of different sounds.

[caress]

i must be having problems...  i'm getting a ton of hf noise/oscillation etc... with or without the diode   
it's not boxed yet, maybe that's the problem?
anyone been having similar issues?

edit:  not as bad once i took off the feedback pot attached to alligator clips...
si/ge diodes get different flavors in the diode position...also using 2 in fb loop or in parallel.

[oldrocker]

I put the in like the second drawing I posted.  I used an SI 4148 diode and didn't try the feedback pot.  There's no room since my enclosure for it is an Altoids tin.  I used a trim pot for the volume pot.  I set and forget it anyways but it's no problem to open the lid and adjust it.

[ambulancevoice]

i must be having problems...  i'm getting a ton of hf noise/oscillation etc... with or without the diode   
it's not boxed yet, maybe that's the problem?
anyone been having similar issues?

edit:  not as bad once i took off the feedback pot attached to alligator clips...
si/ge diodes get different flavors in the diode position...also using 2 in fb loop or in parallel.

that noise/sc maybe actually be apart of it, but i dont know
box it up and see

[fldrvr]

Hey all, first time posting at this site, and a nooB to electroics as well. So hello!

I'm interested in building the Randon Number generator, and especially in using the schem posted here with mods.

My questions are as follows:

If I understand correctly, volume pot (the 100K attached to the 'out' of the circuit) should be a Log pot?

What about the 100k in the feedback loop (under the Transistor 2n3904)? Log or Lin?

And, lastly, I am planing on using a transistor in place of the 2n4401. Anything In particular I should watch out for? I've taken a look at the data sheet for 2n4401. Which parameters of the transistor should I make sure whatever I use to replace most closely matched? Gain (Hfe?), Switching characteristics?, Voltages?

Any comments are appreciated. Thanks 

[doug deeper]

a pn2222/2n2222 should work fine in that spot.