I've been looking for this essay online but can't find it anywhere...does anybody have a link where it is still available?
I can't seem to find it either.
There is a mirror site of Tim E's work, but the Many Faces items are not there.
I don't remember an essay, but I do have the schematics at home. I can get those for you tomorrow.
i couldn't find it either, but i did find a project based on it, at runnoffgrooves homewrecker site...
http://www.home-wrecker.com/multiface.html (http://www.home-wrecker.com/multiface.html)
That is why I posted the link to ROG on the other thread, because I couldn't find this one. Tim moved his stuff, but I don't have the link to the new location and it seems the MFF article was sort of separate. Great Stuff. IIRC I like the Mosfet/Jfet version.
Found it: http://web.archive.org/web/20050513200126/www.geocities.com/tpe123/folkurban/fuzz/fuzzyfaces.html
I believe that Yahoo killed geocities. That is why is original site is gone.
Here is the new one: http://folkurban.com/Site/GuitarEffects-681.html (http://folkurban.com/Site/GuitarEffects-681.html)
WGPT, thanks a million. Great ideas on that page. Jrod, I ran across that new site a while ago, it is so interesting that I think I might lose friends and suffer muscle atrophy from sitting and examining all those options!
Quote from: mordechai on June 03, 2010, 04:26:06 PM
WGPT, thanks a million. Great ideas on that page. Jrod, I ran across that new site a while ago, it is so interesting that I think I might lose friends and suffer muscle atrophy from sitting and examining all those options!
I remember seeing some of his other projects years ago (mainly the "instruments" section of his site), but just found the FX he designed about a year ago. Tim E. has offered a TON to the DIY community with his great little circuits. I have built several of his designs and always looking at doing another. Always a lot of fun.
This is one page we don't want to loose. :icon_cool:
Tim put that FF through the ringer, from many various angles.
Plenty of good Fuzz can be had from 2 transistors.
I remember reading a comment someone made that in a Silicon FF, putting a diode in front of Q1 improves the tone by preventing it from saturating. I emailed someone from the forum about this but I thought I'd mention it since Pete returned us to the basic FF concept...how exactly does the diode accomplish this? Does it matter what sort of diode it is?
Joe Davisson's Antiquity does this.
Yes, it is indeed the antiquity fuzz that I had encountered that introduced this idea. I still don't understand, however, what that diode actually does to the signal. Does it matter if it is Ge or Sil? If it were introduced into a PNP FF, would it need to be reversed? What would it do if it were in front of Q2?
I don't think it needs to be reversed, it's in line with the signal.
Silicon will drop less voltage than GE so it would make a difference.
typically .6ish for SI and .3ish for GE
In this schematic (http://www.diystompboxes.com/analogalchemy/sch/antiquity.html), a negative-going input signal forward-biases the diode, which reduces its resistance and steals a small fraction of the current away from Q1. Less current going into Q1 means less likely saturation. On the other hand, a positive-going input reverse-biases that diode and causes its resistance to increase, which reduces gain for positive-going signals, making cutoff less likely as well. Note that the 100k to ground at the input is also required for this to work as expected.
IIRC Joe labeled that "diode compression" and it keeps the transistor from hard saturating. It is also used in the Vulcans. :icon_cool:
http://www.diystompboxes.com/analogalchemy/sch/vulcan.html
Quote from: earthtonesaudio on June 04, 2010, 12:37:31 PM
In this schematic (http://www.diystompboxes.com/analogalchemy/sch/antiquity.html), a negative-going input signal forward-biases the diode, which reduces its resistance and steals a small fraction of the current away from Q1. Less current going into Q1 means less likely saturation. On the other hand, a positive-going input reverse-biases that diode and causes its resistance to increase, which reduces gain for positive-going signals, making cutoff less likely as well. Note that the 100k to ground at the input is also required for this to work as expected.
Isn't that back to front? Negative-going signals cause cut-off, positive ones cause saturation.
Quote from: merlinb on June 05, 2010, 05:04:03 AM
Isn't that back to front? Negative-going signals cause cut-off, positive ones cause saturation.
Oops, yep. You're right.