Choklitlove's Analog Bit Crusher Layout Errors

[RickL]

Sorry about posting this here instead of directly to the feedback in the layout gallery but I kept getting an error,possibly because I'm not posting from my home computer.

The layout has problems. It looks like Vcc and Vcc/2 have been mixed up in a couple of places. Notably Vcc goes to the inverting pin of IC2A and the non-inverting input of IC2B. Positioning of the 10uF capacitor and one of the 100k resistors which should be part of the Vcc/2 subcircuit seem to support this.

I'll fiddle with it tonight and see if a simple trace cut and jumper will solve the problem.

Rick

[choklitlove]

did you purposely call me %^&*litlove?

[widdly]

hehehe

[$uperpuma]

:yikers:

[calculating_infinity]

   How did I not notice that the first time I saw this post.

[Paul Perry (Frostwave)]

  How did I not notice that the first time I saw this post.

Guess it was subluminal.

[choklitlove]

all's cool (so long as it was accidental!).

i have no doubt that there are errors in this layout, and probably a lot of my layouts.  unfortunately, i barely have enough time to make them, let alone debug them.  you guys have at it, and if you can find the errors, or if you have ideas, i can update the layout.  eventually i will get to building this, but not any time soon.  i hope this layout will work soon because it seems cool.

[Hambo]

hehehe

Agreed.  ahahaha

[RickL]

        

How did I manage to do that? It was purely accidental I assure you. I'll try to change it if I can but I think it's too late.

I found a couple of more problems. Two of the resistors are the wrong values and the pinout for the FET is wrong. Also I'm not sure why you used a 0.0033uF cap in place of the 0.1uF on the schematic. I did the corrections on my build and I'm at least getting sound out of it, but no effect at all. I'm not sure exactly what it should sound like but it looks like the bottom part of the schematic is an oscillator of some sort that either turns the FET on and off or changes the resistance between the source and drain in some manner. In any case I get either a pretty much straight through sound or a quieter, duller version of the dry sound depending on how I orient the FET (swapping drain and source).

I've been out of town this week (hence the late reply on the unfortunate thread title) so I haven't had a chance to try different FETs. I may get a chance to try tonight but I'm leaving in the morning for an out of town soccer tournament and won't be back until late Monday so there's a good chance I'll get nothing done. Early (6 o'clock!) Tuesday morning sees me on a flight to Ottawa so unless someone replies to this in the next couple of hours you may not hear from me for a week.

[choklitlove]

i'm glad you're tackling this.  i posted it a while back somewhere with hopes of someone looking at it for me.  it's the biggest layout i have tried, and after you've been looking at something for so long, you miss things quite easily.  i'll try to get to correcting it soon.  let me know if you find more problems.

[oldrocker]

It should sound close to the Bug Crusher sample on my website.  I made mine from the schematic below so just substatute a 324 quad and it should be close.  I changed R7 100K to a 47K (R3 on Choklit's layout I believe) and the .0033uF cap to a .1uF other then that it should work.  The knob has a small area that dials in the effect.  The sound sample doesn't do it justice since many more sounds can be made from that small pot travel.
http://www.logmonster.com/images/full/?pic=AnalogBitCrusher_1174772303-422-14887.jpg
http://randallbarnett.homestead.com/SoundSamples.html

[Austin73]

Hi Randall, do you have layout for your working bit crusher that you could share with us less intelligent chaps here?

Cheers

Aus

[RickL]

It looks like I found a different version of the schematic. The two resistors that I called wrong actually match the values on the schematic you posted. The schematic I have shows R7 and R8 as both 1M. First chance I get I'll swap them back. The 0.0033uF cap I was asking about (C4) is shown as 0.1uF on the schematic I have. I'll change it too and see what happens. It might be that the only fix that was required was for the Vcc/Vb.

[oldrocker]

Sorry I didn't use a layout when I built mine.  As usual I did the layout as I perfboarded it.  The 100k resister (R7 in the schem I posted) for me had to be changed to a 47K (R3 in Choklits layout) for mine to work at all.  As for the .0033uF (C4) I made mine a .1uf since it worked better for me that way.  There is the schematic below which shows a 1M for R7.  That didn't work at all in my circuit so I made it a 47K and it fired up.
Also for R8 I used a 100R and not 1M.
http://www.logmonster.com/images/full/?pic=24911275843_1174794150-422-14886.jpg

[gez]

Anyone here using opera should check the tab for this page.  It reads '%^&*litlove's Anal'

Sorry!