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First OD circuit

Started by Snappy Charles, August 08, 2010, 07:24:52 PM

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Snappy Charles

At least my first proper one.  Or so I think.
If it's not an issue, I'd like some pointers as to what might be dead wrong with this circuit so that I may be able to correct these problems in the future.

The controls are supposed to be a single knob on the outside which controls the voltage going into the pedal, as well at two switches.  The first switch, an SPDT switch, controls the clipping circuit (silicon or germanium) and the second switch, an SPST switch, will allow the pedal to oscillate when switched on.  The colored solder pads are coded as follows:
Red- Input
Blue- Output
Green- 9v in
Orange- To 3PDT switch (LED only)
Brown- Ground out

Thanks.

PRR

> what might be dead wrong with this circuit

Why would you think it is wrong?

What is it doing? What did you think it would do?

Did you draw a schematic?? The LM386 is simple, but not SO simple that I can keep a pictoral straight in my head when following the function.

Offhand:

Vts's effect is to short-out the source, which is not usually what we do in audio.

The 386 drives a largish cap then grounded diodes. The idea is that the diodes short-out the 386; the reality is that a 386 can smoke many Ge diodes and maybe Si diodes. You NEED some series resistance between the 386 and the diodes.
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Earthscum

I never thought about the current the 386 can put out frying small signal diodes. I don't play with them much, but that's good thing to keep in the back of your head.
Give a man Fuzz, and he'll jam for a day... teach a man how to make a Fuzz and he'll never jam again!

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Snappy Charles

I probably should have mentioned I'm an idiot with a soldering iron who has just enough common sense to work out a simple circuit and consult you guys about it.  So, I mostly know nothing about how electronics work.

Where's the awkward laugh emoticon right when you need him?

smallbearelec

Quote from: Snappy Charles on August 08, 2010, 11:30:16 PM
I'm an idiot with a soldering iron

Hi--

Stop flying blind and learn to use a solderless breadboard.
http://www.smallbearelec.com/HowTos/Breadboarding/BreadboardIntro.htm

When you understand how the tool works, find a known-to-work schematic or layout for an LM386 OD (if that's your preference--I would use a standard op-amp; the LM386 is more typically used as a small power amplifier.) Set the circuit up on the breadboard and make it work there before you commit to solder.

Here is an op-amp OD/Distortion on breadboard that you might want to try:

http://www.smallbearelec.com/HowTos/BreadboardICDist/ICDist.htm

The version that is based on the TL071 is simple, cheap and very effective. Could be snipped out and built as a single stage if you want.

Brymus

Interesting though ,I have put resistors on the end of almost every circuit I have tried except the 386 ones.
Neat idea if you get it to work the way you want.
Maybe try the volume pot with C1 and take the output off the wiper ?
IDK
I would start with the data sheets they have some examples to work with,might prove useful to you.
I know I have fried a couple of 386 ICs having fun expirementing with em.
I'm no EE or even a tech,just a monkey with a soldering iron that can read,and follow instructions. ;D
My now defunct band http://www.facebook.com/TheZedLeppelinExperience

ViolenceOnTheRadio

My second circuit was an LM386 design used to replace the crackly overdrive I first built.
The LM386 circuits are in my opinion, novelties. Once you build something transistor/op amp driven you pretty much realize just how elementary you started out lol. All the filtering and clipping diodes in the world on these things still wouldn't get them to pass pinch harmonics through to my amp. Great clean sound though, work great if you want something to drive a tone stack and serve as a clean channel.

They are however the foundation that gets many of us started.
Not to be rude but if I were you, I would look for something else to build lol.





Brymus

Quote from: Brymus on August 08, 2010, 11:43:30 PM
Interesting though ,I have put resistors on the end of almost every circuit I have tried except the 386 ones.
Neat idea if you get it to work the way you want.
Maybe try the volume pot with C1 and take the output off the wiper ?
IDK
I would start with the data sheets they have some examples to work with,might prove useful to you.
I know I have fried a couple of 386 ICs having fun expirementing with em.

DOH I meant diodes/clippers  :icon_redface:
The burning crunch,and my 386 pre amp both do pinch harmonics pretty well.
I'm no EE or even a tech,just a monkey with a soldering iron that can read,and follow instructions. ;D
My now defunct band http://www.facebook.com/TheZedLeppelinExperience