Final Info. Scooch Box 04-10-11

[Goodrat]

Schematic:
http://www.rickviola.com/images/ScoochSchem041011.jpg

Wiring:
http://www.rickviola.com/images/ScoochWiring041011.jpg

Layout:
http://www.rickviola.com/images/ScoochLay041011.jpg

Picture front:
http://www.rickviola.com/images/ScoochBox.JPG

Picture inside:
http://www.rickviola.com/images/ScoochBoxIn.JPG

When I get around to it I will make some MP3's

[Goodrat]

For any minor tweaks I do, I will just replace the file and change the date in the picture.
Made two already today. (C3 and also C5 A and C were swapped).
R9 on my original I made about 20 years ago was 100 ohms (pretty low). It sounds great because somehow that cuts the low end of the op amp in such a way that it resulted in a nice punch on muted power chords.
But then the mid boost across R9 would not work well on this one if I did that. Then I also would have to tweak the C5 caps again.
I need a comprise. Maybe lower R9 to 470 and double the C5 caps.
Stay tuned.

[askwho69]

WOW NICE ONe! hope to hear clips soon

[Goodrat]

OK, Changed R9 lower and C5 values. Much better.
I may also change the drive pot to 100K. More gain please!!

[Goodrat]

Drive pot now 100K

[ayayay!]

Very interesting.  Thanks for sharing this.  I have this weird thing about seeing inductors in circuits.    I only see one in the top, right of center.  Where's the other one?  And have you tried other amps?  Just curious as to why you chose the TL082.

And yes, you must "get around to it" asap.   

[Goodrat]

Look on each side of the clipping LED's for the inductors.
The mid boost one needed a higher resistance coil so as to not overdrive the stage.
(could have added about 150 ohms in series if I used the lower ohm coil).
The one on the output wants a low ohm coil,
which I usually wind myself (very low ohm toroid) but I picked a coil that was about 30 ohms
just to see how a stock part worked.
The output coil causes a phase distortion around the resonant frequency. At least that is what it looks like.
Two caps switch in two different sounds. Very tube like.
I tried a better op amp (OPA2604) and it did not do this, or it was very slight. So that is interesting.
Coils give an extra unique character I think.
Lots of voodoo. Ringing, saturation, who knows.
If anything, there are ideas here to tinker with. Mid boost, SP3T switches and tuned phase distortion.
This weekend (4-16-11) I will do a Youtube vid.
That's the plan anyway.

[rnfr]

looks cool.  I've used small value inductors in place of bypass caps off of transistor emitters before with interesting results.   looking forward to hearing it!

[Goodrat]

Here is a Youtube demo:
http://www.youtube.com/watch?v=xxpLJRRc_yw

[Goodrat]

No comments?

[askwho69]

what did you use in recording? sound so thin to me

[Goodrat]

I recorded separately but ended up just using the audio from the sony camera.