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DIY Stompboxes => Building your own stompbox => Topic started by: sir_modulus on September 06, 2004, 05:56:46 PM

Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: sir_modulus on September 06, 2004, 05:56:46 PM
Ah the wonder of the "Ten Year Old Sandwich Fuzz", a three segment very standard Opamp based soft diode clipper. What do you guys think? any improvements, suggestion, critism (good)?

Here it is:
http://img.photobucket.com/albums/v439/sir_modulus/TYOS1.gif

P.S. note that the image is HUGE (anyone know how to resisze a gif?)

Thanks!!!
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: RDV on September 06, 2004, 06:07:11 PM
(http://img.photobucket.com/albums/v165/rickydon/TYOS1.gif)
What's it sound like?

When you want to resize a GIF, one way is 2 save as a jpeg, then you can resize with typical photo editing software. In this case I saved it as a bitmap with MS Paint, then opened it and resized with MS Photoeditor, then opened the bitmap with paint and saved as a GIF again.

RDV
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: Marcos - Munky on September 06, 2004, 06:13:19 PM
Looks fine for me. Maybe with a good 3-band EQ you get a cool overdrive. The three gain pots looks like it~s a versatile unit. You have soundclips:
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: Ansil on September 06, 2004, 06:18:18 PM
i am resizing it for you will put it on photobucket so you can copy it and reloadit to yours



(http://img.photobucket.com/albums/v210/ansil/tyozfuzz.gif)



i dropped it straight into pbrush hit resize 50/50  save as tyozfuzz.gif
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: cd on September 06, 2004, 07:11:28 PM
You should put some EQing in between stages, as is it will likely sound noisy and/or harsh.  Try increasing the the 50pf caps.
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: sir_modulus on September 06, 2004, 07:18:19 PM
k will do. Adding the baxendall 3 band using the remaining half of an OA. now my other question. If I max out all the controls, I'm going to get three OA with gains of 251 each. Is this too much?
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: cd on September 06, 2004, 07:27:39 PM
Quote from: sir_modulusf I max out all the controls, I'm going to get three OA with gains of 251 each. Is this too much?

Nope, you've got the diodes there clamping the signal.  Depending on your layout/wire routing, it could still oscillate though.
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: Peter Snowberg on September 06, 2004, 07:30:08 PM
Since everything is DC coupled between the stages, you can eliminate the two 1M resistors that feed Vr to stages 2 and 3. The other option is to add some 10uF coupling caps between the stages. :D

Looks very cool! 8)
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: brett on September 06, 2004, 07:37:49 PM
Hi. It's an interesting idea to use Ge then Si then LEDs to clip.  I haven't thought it through, but would a 4PDT let you switch the Ges and LEDs around?  ie LEDs first?
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: sir_modulus on September 06, 2004, 08:02:07 PM
that'd be real hard....I'll think and see if I can find a way (a barely have enough money to afford 1 3PDT per box, let alone 1 3PDT and 1 4PDT per box. I could make it in a later version that you have three rotary switches to decide which clippers to use each stage, I'll post the rev 2 schematic sometime tomorrow.
Title: You know...
Post by: David on September 06, 2004, 09:39:51 PM
...  nice work, Sir Mod!  I think you're on to something!

Are you fishing for ideas?  I actually have a couple.  Try these:

JFET input buffer before op-amp 1 (I know, it's actually redundant, but it could help give you that tube vibe...)

Capability of switching between bridged diodes (soft clipping) and diode pair to ground (hard clipping) in first stage.  I would think this is the one you want to pound.

Converting that last stage from a distortion stage to a tone control stage.

Where does the "three year old sandwich" thing come from?
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: sir_modulus on September 06, 2004, 10:26:41 PM
The new TYOS fuzz is almost ready (I added a bunch of new stuff including an active 3 band EQ, LPB output buffer(thats a whole LPB right on the output folks!), etc...) I'll post it tommorow when it's ready.

Till then, bye and Thanks for the input (no pun intented),
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: Brian Marshall on September 07, 2004, 01:20:15 AM
the big thing that i see that might be a problem is low frequencies.

since you have giant caps followed by large resistors on the input and output.  it will not attenuate any low frequencies, at least not in the audio range.  this is a recipe for muddieness.  you also might want to lower the the cap values to ground in your feedback loops, especially in the first stage.
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: bwanasonic on September 07, 2004, 01:44:53 AM
Looking at this makes me envisage a LEGO-like fuzz construction toy, with little modular fuzz/distortion building blocks. I have vague memories of an electronic construction set when I was kid that had little blocks with electronic schematic symbols on top that you could arrange into various circuits. Kind of a LEGO meets 200-in-1 electronic projects kit thingy.  Now I see Germanium mutated Gameboy cartridges...

Kerry M
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: cd on September 07, 2004, 08:28:53 AM
Have you built/breadboarded this thing, or is it all theoretical at this point?  If the latter, breadboard the circuit at least and actually play into the thing - you'll get a better feel for clipping and different topologies.
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: sir_modulus on September 07, 2004, 09:17:52 AM
it's concept but read the new post. Thats the new circuit. I'll build that one on pad per hole board.
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: Mike Burgundy on September 07, 2004, 12:10:23 PM
Bwana:
QuoteLooking at this makes me envisage a LEGO-like fuzz construction toy, with little modular fuzz/distortion building blocks.
Have a look here:
http://www.geofex.com/Article_Folders/FXbus/fxbus.htm
Title: New Overdrive circuit made by me! Need some feedback(no pun)
Post by: WGTP on September 07, 2004, 12:45:52 PM
Check out the post about Mosfet clippers. 8)