Insanity Box

sm3000 · April 24, 2009, 09:43:03 PM

As first and probably only project I decided to do the Insanity Box (by Aaron Nelson). I succesfully etched the pcb using the PnP / acid method..here's a picture of the board. I trimmed all the green unused parts on the sides.

Now I'm wating from some parts I ordered on the internet, and already drilled holes on the board. Are the two diagrams that I developed right to connect the pots, jacks and switch?

And also I noticed on a french forum that they question a capacitor next to one of the two J201 fets. Any thoughts on that?

Your help is much appreciated! I'll keep you posted!

aron · April 24, 2009, 10:20:07 PM

The capacitor is a .11uF, but just use .1uF. I originally had a .1 and .01 paralleled.

sm3000 · April 24, 2009, 10:39:31 PM

thanks! are the pots connected correctly? on the prototype you built (I presume is the same you used for the audio samples) which types of diodes did you use 1N914 or 1N34A? Two for symmetrical or three for asymmetrical dist?

sm3000 · April 26, 2009, 02:36:16 AM

Here's the populated board. I'm still missing a 100K trimpot that I will add asap.

MarcoMike · April 26, 2009, 05:59:27 AM

what a vintage looking board...

sm3000 · April 26, 2009, 08:57:16 PM

Ok I completed the board with the missing trimpot and wired everything to switches and jacks as the drawings show in my first post.
The bypass works, the pedal doesn't. when it should be active no sounds come out.
ANYONE TO HELP ME WITH THE DEBUG?

aron · April 27, 2009, 03:24:57 AM

First verify that you are getting correct voltages on the components. Check the IC first.

danielwarner · April 27, 2009, 04:03:45 AM

Your TL071 is socketed backwards, if it is a TL071, I can't tell from the photo. What op amp are you using?

sm3000 · April 27, 2009, 05:49:33 AM

Aron I will buy another multimeter asap since I can't find mine anymore.

Danielwarner I'm using a JRC4558D and yup you're absolutely right, it's backwards..I turned it around but still no sound..

anchovie · April 27, 2009, 07:03:01 AM

The TL071 is a single op-amp and the JRC4558D is a dual op-amp. They have different pinouts so a 4558 isn't going to work here at all.

sm3000 · April 27, 2009, 07:29:40 AM

doesn't aron use a 4558 in his schematic? http://www.diystompboxes.com/pedals/insanity.GIF

Mike Burgundy · April 27, 2009, 08:34:16 AM

Yup, but just one half.
That board is definitely made for a TL071, so a 4558 won't work.

aron · April 27, 2009, 12:08:22 PM

Good catch Mike!

sm3000 · April 27, 2009, 03:02:21 PM

No wonder it doesn't work! Let me get a TL071 and try again! do you know if Radio Shack carries them?

thegman54 · April 27, 2009, 03:18:57 PM

yup

sm3000 · April 27, 2009, 07:08:16 PM

GREAT! IT WOOOORKS!!!

I just went to RadioShack and got a 741 opamp, since they didn't have the TL071.
The only problem is that it sounds thinny and the bypassed/dry signal is senisbly louder than when the effect is on. Is it because of the 741 opamp?

Just for your consideration here's are the different pinouts of the TL071 and the 4558/TL072

TL071

4558/TL072

aron · April 27, 2009, 07:10:17 PM

COOL! You got it working! Congratulations!

sm3000 · April 27, 2009, 07:50:49 PM

THANKS!!! but it doesn't sound anything close to the samples you recorded years ago and I'm trying to figure out why (maybe because of the LM741 instead of the TL071?).
Did you build it with the exact same parts and values of this? http://www.diystompboxes.com/pedals/layouts/inlay.jpg
What diodes did you use?
Did you use a tl071?

aron · April 27, 2009, 07:57:56 PM

I hand-wired it using perfboard. ooops I used a TI RC4558. I used three 1N914.

sm3000 · April 27, 2009, 08:06:50 PM

cool i'll swap out the two 1N34A for three 1N914. do you think the volume drop is due to the opamp?

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Insanity Box