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DIY Stompboxes => Building your own stompbox => Topic started by: arawn on August 02, 2007, 06:03:14 PM

Title: 2 stage IC Fuzz
Post by: arawn on August 02, 2007, 06:03:14 PM
I wonder if this would work?? Does anyone see anything wrong with the way I have it wired??
(http://img297.imageshack.us/img297/9164/2stageicfuzzou4.gif)][URL=http://imageshack.us](http://img297.imageshack.us/img297/9164/2stageicfuzzou4.gif) (http://[url=http://imageshack.us)
By arawngwydion (http://profile.imageshack.us/user/arawngwydion) at 2007-08-02[/url]
Title: Re: 2 stage IC Fuzz
Post by: theonlyrobkeyser on August 02, 2007, 06:10:53 PM
I can't seem to open any of those links and get an image that's large enough to really look at.
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 02, 2007, 08:37:11 PM
okay try this one http://s200.photobucket.com/albums/aa266/arawngwydion/ (http://s200.photobucket.com/albums/aa266/arawngwydion/)
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 02, 2007, 08:39:29 PM
or we can try this
(http://i200.photobucket.com/albums/aa266/arawngwydion/2stageICfuzz.gif)
Title: Re: 2 stage IC Fuzz
Post by: theonlyrobkeyser on August 03, 2007, 12:31:30 PM
I'm no expert, but if your going into the inverted and non inverted inputs with the same signal, won't they cancel each other out?

Other than that I don't see anything that would make it not work, but you may want to make some changes to optimize it's sound.
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 03, 2007, 08:19:47 PM
Basically I'm looking for suggestions this is loosely based on a fuzz i saw at ss guitars And i don't know who to credit for it but the fuzz there is a single 386 with no pots or trimmers just a few caps. I was trying to get a very simplified version of a multi stage fuzz
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 04, 2007, 02:45:04 AM
Try throwing caps C1 and/or C2 across the two inputs of the op-amps for a slight octave effect. Have you got this one working? I was going to breadboard something similar this weekend funnily enough but hadn't got to figuring out how to work the gain... you have given me some ideas there!
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 04, 2007, 04:07:19 AM
you need to ground pin 2
and just use input three
also, are the diodes intended to be clipping diodes?
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 04, 2007, 06:52:07 PM
yeah the diodes are intended for clipping, no i haven't built this yet I have to get the pots, but i want to hear what it sounds like. I like the idea of a slight octave, I missed that but i still pretty new at this> :o
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 04, 2007, 07:18:37 PM
The clipping diodes need to be grounded
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 04, 2007, 09:04:32 PM
so it should be a little more like this ??

(http://i200.photobucket.com/albums/aa266/arawngwydion/2stgicfzz.gif)
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 05, 2007, 02:12:24 AM
Pretty much, yup!
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 05, 2007, 03:36:21 AM
the diodes wont clip at all if you dont ground them
this is how they can be configured
(the one with four diodes will clip more)
(http://img441.imageshack.us/img441/2299/sgdfgdfgdfwz7.jpg)

also, id really really clean up that layout too
i can barely tell whats going on
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 05, 2007, 10:28:42 PM
I would also suggest that you put a volume/level pot over the whole circuit too. I use a 100k log for this. (Reading from right to left when looking at the bottom of the pot) Lug 3 to circuit output, lug 2 to switch, lug 1 to ground.

Quote from: theonlyrobkeyser on August 03, 2007, 12:31:30 PM
I'm no expert, but if your going into the inverted and non inverted inputs with the same signal, won't they cancel each other out?

The LM386n has a dual input, hence why putting a cap across them gives the octave effect. It still gives a half decent sound when set up the way he had it in the first diagram, but the slight octave makes for a nicer sound in my opinion.
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 06, 2007, 01:58:16 AM
also, i would use aluminium electrolytic polarised caps for the output caps

btw, have you built any other pedals already?
or designed and built others of you own before?
Title: Re: 2 stage IC Fuzz
Post by: theonlyrobkeyser on August 06, 2007, 01:38:05 PM
Do the diodes need to be connected directly to ground?  Aren't the clipping diodes in the TS just in the feedback loop of the IC?  I guess the TS diodes are grounded through a resistor and cap on their way to the second IC stage, but I kind of thought that just having two oppositly directed diodes would clip if the signal was high enough.  But, I'm asking because I really don't know and I would like to know. 
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 06, 2007, 09:42:28 PM
Never designed and just started building a couple months ago. The clean boost from here and that ultra simple fuzz http://www.ssguitar.com/index.php?topic=378.0 (http://www.ssguitar.com/index.php?topic=378.0) at the bottom of the page
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 08, 2007, 09:01:24 AM
Quote from: theonlyrobkeyser on August 06, 2007, 01:38:05 PM
Do the diodes need to be connected directly to ground?  Aren't the clipping diodes in the TS just in the feedback loop of the IC?  I guess the TS diodes are grounded through a resistor and cap on their way to the second IC stage, but I kind of thought that just having two oppositly directed diodes would clip if the signal was high enough.  But, I'm asking because I really don't know and I would like to know. 

opamp and the and some transistor fuzzes have the diodes connected in different ways
but output clipping diodes need to be connected to ground in order to clip
unless its crossover distortion
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 09, 2007, 09:09:19 PM
How does this look I took the switch out for now, and does it clarify what I am doing??
gonna bb this tomorrow night.
(http://i200.photobucket.com/albums/aa266/arawngwydion/2stageicfuzzcleanedup.gif)
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 10, 2007, 04:13:48 AM
A couple of pointers... Wiring this up the way you have suggested there WILL NOT WORK! You have grounded the signal straight after the first IC output and again in the same place after the 2nd IC. Try running a jumper wire from the other end of the diodes to ground (where I have indicated with the arrows).

(http://usera.imagecave.com/llama_police/2stageicfuzzcleanedup.gif)
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 10, 2007, 08:57:56 PM
woopsy I missed that one
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 10, 2007, 11:24:29 PM
so more like this will avoid the ground loop and maximize clipping

(http://i200.photobucket.com/albums/aa266/arawngwydion/2stgicfuzzx3.gif)
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 11, 2007, 03:43:33 AM
Try this dude, you are getting way off track. Keep the pots and jacks how you have them, but try doing the rest of the layout kind of like this

(http://usera.imagecave.com/llama_police/blerblerbler-copy.jpg)
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 11, 2007, 05:11:19 AM
here man
i drew up a schem with some of my own suggestions
the pots are 1k, 10k is to much, also i recommend a volume pot at the output, but it not really that important so i didnt draw it on there
the 10uF electro caps after the gain pot is so when the pot is at maximium resistance the ic will be at 200x gain
the switch is to cut of the first set of clipping diodes
cause there is a chance that you may find that there is to much clipping
you can do the same with the second set of diodes
(http://img241.imageshack.us/img241/5342/2stageicfuzzschemfj0.jpg)
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 11, 2007, 10:35:08 PM
how about like this ????

(http://i200.photobucket.com/albums/aa266/arawngwydion/2stgicfuzzx3.gif)
Title: Re: 2 stage IC Fuzz
Post by: Cardboard Tube Samurai on August 12, 2007, 12:58:33 AM
I give up!  :icon_confused:
Title: Re: 2 stage IC Fuzz
Post by: oskar on August 12, 2007, 10:08:59 AM
Charles (arawn... two Charles in here ), you need to step back a bit in your engineering career, I think.  ;)
1. Try just to copy Cardboard Tube Samurai's drawing, as an exercise.
2. You have two identical stages!? Well, make them look the same on your drawing to...

:) skar
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 12, 2007, 01:36:33 PM
Kay i think i got it now
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 12, 2007, 01:38:21 PM
thanks Guys I really appreciate the input  ;D
Title: Re: 2 stage IC Fuzz
Post by: ehofherr on August 12, 2007, 05:17:11 PM
  Okay, so I went ahead and made a layout using Cardboard Tube Samurai's schematic <Please correct me if Im wrong here>:

(http://home.comcast.net/~ehofherr/images/2_Stage_IC_Fuzz_a.jpg)

  I would breadboard it if I were you.  You'll notice the DPDT switch is an ON/OFF/ON switch.  Use that to clip one stage, both stages, or no stage at all.  I suggest you placing a temporary switch between D2 and C5.  One lug going directly to OUT.  The other lug connecting to C5.  You'll be able to tell what difference using 1 stage and 2 stages.  Please provide feedback on this, otherwise I may breadboard it with my son as a learning experience.
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 12, 2007, 10:57:27 PM
nope that looks about right to me, in fact it looks better than what i had in mind You did great work!! I don't know when i'll get around to bread boarding it, so go ahead and have fun with your son!
Title: Re: 2 stage IC Fuzz
Post by: ambulancevoice on August 13, 2007, 01:47:18 AM
hey nice about using on off on switch for the diodes!
Charles, keep my schematic
and yeah, i second the bread boarding
also, probably switching out the diodes will turn it into just a plain distortion thanks the two 386s
im not totally sure if this thing will even be a fuzz
Title: Re: 2 stage IC Fuzz
Post by: arawn on August 13, 2007, 08:43:58 PM
cool thanks again guys
Title: Re: 2 stage IC Fuzz
Post by: wampcat1 on August 13, 2007, 10:41:15 PM
Quote from: arawn on August 03, 2007, 08:19:47 PM
Basically I'm looking for suggestions this is loosely based on a fuzz i saw at ss guitars And i don't know who to credit for it but the fuzz there is a single 386 with no pots or trimmers just a few caps. I was trying to get a very simplified version of a multi stage fuzz

I think that is dragonfly's fuzz, the 386 fuzz.