Slambox extra components?

[Hyatt]

Was just wondering why the slambox has more components than the other layouts I've seen for the sh0.  Has the real sh0 changed design or are these custom mods?

[irmcdermott]

I think that the only extra components on there that you may not see in other layouts are R1 and R6.

R1 acts as a pulldown resistor to help with the "pop" that you can sometimes get when you switch the effect on and off. His layout is designed so that you can hook your LED directly to it, so R6 is the LED resistor.

I don't have any other layouts in front of me, but off the top of my head, that's what I think you are seeing. Someone correct me if I'm wrong.

Ian

[Hyatt]

Probably should've been more specific.  There's the 2 added resistors that you mentioned that make sense.  Theres also an added cap and the diodes here are zeners.  This is the layout I was going to use before I found this site (which is pretty awesome). 

http://www.aronnelson.com/gallery/main.php/v/DRAGONFLY-LAYOUTS_0/album14/Z+VEX+SHO+LAYOUTS.GIF.html

And theres a few floating around on freestomp and diystomp that use the same parts. 

[irmcdermott]

Ok, I've looked around and did some research and I think I have some answers. Some one PLEASE chime in if I'm mistaken. I try to learn more every, but by no means am a guru yet, but from what I can tell here is what is going on with the extra parts.

Zener Diodes:
It looks like all newer real SHO's have changed to use the zeners. They are protecting the transistor from blowing. If you read the description on the originals site, he states that all newer SHOs have a "diode protection circuit." That would be the zeners working their magic.

Extra Cap:
That is the 47uF cap that is acting as a DC filter, to help reduce noise that you can get from using wall warts and such.  

Neither of these things will affect the tone of the circuit.  I actually just built one of these a few weeks ago and can't tell the difference between it and the original.

Brian (madbean) is in the process of moving right now and I'm sure once he gets settled he can correct me and/or shine some light on it, but I'm pretty certain that is what is going on. Hopefully this is helpful.

Ian

[Hyatt]

Thanks dude, answered the question perfectly.  Gonna put one together this afternoon and check it out.

[Hyatt]

Damn, don't have a 5.1k resistor.   Is this a part that can be substituted by like a 4.7k or something close?

[oldhousescott]

4k7 should be fine there.

[Hyatt]

Cool, thanks.