wobbletron, or pwm?

[pinkjimiphoton]

hi, been reading  alot about both these circuits...and bought enough parts to build both, almost...

but...i gotta couple questions.

can i substitute one of the mpsa18's for a silicon, maybe a 2n5088 or something in the wobbletron? i only have one mpsa18 (duh)...
and if so, does it matter which?

also, what are your thoughts on the pwm...it seems both of these circuits get mixed reviews as to how easy they are to get up and running.
is there a huge diff tonally to the ugly face with the pwm? the clips i've heard with the lfo mod sound a LOT like some of the stuff i get out of my ugly face.

as always, thanks in advance!!
peace
jimi

[glops]

I've tried a few Escobedo circuits.  If I were you, I would test these out on a breadboard first and do some fine tuning.  As snippets, some of them make great standalone pedals but I think they are provided by the designer as building blocks that can be expanded and tweaked.  I tried out a Simple square shaper awhile ago and didn't get any good sounds because I was substituting some parts.  Have it now on bread board with close values and love it.  Since these circuit are pretty small, easy to bboard and tweak or audition, and then decide what to commit to in a box.

[Processaurus]

wobbletron doesn't work as drawn, always test your circuits before committing to a finished project:

http://www.diystompboxes.com/smfforum/index.php?topic=33462.msg233056#msg233056

[1878]

I use the PWM as a straight fuzz without any modulation & I love it.

[nordine]

i bulit the wobbletron years ago and i remember it being cool, not vibrat per se, but sort of chopped-vibe, sounds like a delay... weird as it sounds, it does, because of the pseudo repetitions

didn't have to mod it in any way

[nordine]

now that i think of it, could it be modded to work with one opamp?
one side doing the darlington work, and another in a phase45 like oscillator fashion?

for reference:

[pinkjimiphoton]

thanks so much for the replies...in for a dollar, lol...

gonna build the pwm...cuz i have the parts,and it seems like a cool toy to add to the arsenal.

i'll breadboard the wobbletron first, to see if it works for me..thanks for the heads-up~

[p_wats]

I breadboarded the PWM a while back and have always meant to actually build it, as I loved the sound. Great choice.

[deadastronaut]

hi jimi,

i made a crude vero for some other guy on here ages ago, i never built it myself though ok..

but iirc the guy made it ..turn the diode around and the 2n3904...build at your own risk ok!...

check it over with the schematic!..

[pinkjimiphoton]

thanks rob.
i breadboarded it, it seemed to work (the basic original version) so i slapped it together on some vero last nite.

one thing i learned is to NEVER use "premium grade solder" included with a parts order...oh my god, this stuff sucked....!!!!

anyways, i did get it working, sorta kinda, but it sounds pretty much just like a really gnarly fuzztone without a lot of output.

while dicking around with it, i discovered it had way more output if i bridged pins 1 & 2 of the 40106.
weird.

also, the pwm pot doesn't really seem to do anything whatsoever....

i went with this particular layout :



as it seemed to be on the money with the schematic.

i should have built the more complex one, but i'm running out of some parts and figured i'd learn more (and feed my addiction more) if i built a couple projects rather than one.

anyways...any ideas why the pwm pot doesn't seem to work?

am i gonna screw something up by bridging the pins on the schmidt trigger chip as i did?

also discovered that bridging pins 2 & 3 as well give enough output to probably drive a speaker...toying with the idea of adding a pot there to give it more balls.

the high end without the jumper i added fizzles out pretty bad...but with it, a huge increase in sustain, gain, and volume.

thanks in advance!!
peace
jimi

[1878]

The stock PWM without the LFO is quite a loud effect. Also, the pulse width control has a big effect on the overall sound. I used this layout & built it on perf...

http://www.aronnelson.com/gallery/main.php/v/Matts-layouts/PWM_PCB.gif.html

This is my completed build and I love it. Full of Fuzzy goodness.

[pinkjimiphoton]

i posted a layout of the pwm as modded by me...it's in the forum, if anyone is interested. it seems to have made it a much more usable effect, but again, i can't tell if the pwm really does much...is it subtle, or really strong...the effect of it, i mean..?

[p_wats]

If your PWM isn't doing much then I'm inclined to think it's not working properly, as it's a pretty crazy, loud and very noticeable effect.

[pinkjimiphoton]

yah, i think i smoked the 40106 chip. my local parts supplier is out of them, so i'm putting it on the back burner til they restock it. i came up with a couple mods that change the character from bizzarre-o super mario land to a very useable distortion, so i guess that's good. i put switches on it yesterday for the mods (jumping pins 1&2 of the 40106, and adding a 47k/.01mfd rc network across pins 7& and it totally changes it's vibe and makes it useable for a bunch of sounds it didn't get before...no sputter, less fiz, more dynamics and guitar volume friendly.
looking forward to getting a new chip to try it again soon.

[pinkjimiphoton]

pwm mods i did video...

http://www.youtube.com/watch?v=7qna3Z0ETN0