yet another FF clone :)

[Joe Davisson]

http://diystompboxes.com/analogalchemy/pedals/antiquity.html
have fun

[brian wenz]

Hello Hello Joe--
    Great...thanks for the circuit!  I love FF circuits.....I can always learn new "stuff" with 'em.
Why adjust the bias with Q1 instead of Q2's collector??  Any tonal  advantages?
Thanks again--
Brian.

[brian wenz]

Hello Hello Joe--
    Great...thanks for the circuit!  I love FF circuits.....I can always learn new "stuff" with 'em.
Why adjust the bias with Q1 instead of Q2's collector??  Any tonal  advantages?
Thanks again--
Brian.

[Phorhas]

Great... another fuzz I would be able to sleep until I build... thnx a bunch, JOE!

I'm kidding, it sure looks interesting...gotta build it!!!!

Thnx Joe, really




P.S.

Why adjust the bias with Q1 instead of Q2's collector?? Any tonal advantages?

I think it's a typeO

[Fret Wire]

P.S.

Why adjust the bias with Q1 instead of Q2's collector?? Any tonal advantages?

I think it's a typeO

No, it's correct. Biasing a fuzz with Q1's collector resistor works really well. Most people bias with Q2 only, and pay no mind to Q1's voltages. As long as Q1's emitter is at zero, they are happy. Biasing by Q1 is also how Joe's got his Fuzz Calculator set up. Now that he's tweaked it some more for Ge's, I'll have to test it again. Before, the Ge tranny voltages were spot on except for Q2's collector being a bit high. For Si, it's completely on.

[Joe Davisson]

The way Q1 is biased, it is very sensitive to changes in beta value (hfe). Q2 is much less sensitive. Q1's collector resistor either raises or lowers the gain to the appropriate level. Compare these two pedals:

1. Q1 beta = 500, Rc1 = 5.6k
2. Q1 beta = 100, Rc1 = 28k

The gain of both stages is approximately the same. Now compare differences in Q2's beta value and it's effect on the calculated resistor value:

1. Q2's beta = 700, Rc1 = 5.67k
2. Q2's beta = 300, Rc1 = 5.63k
3. Q2's beta = 100, Rc1 = 5.49k
4. Q2's beta = 50, Rc1 = 5.29k

Not much difference at all. I chose to do it this way so that the pedal compensates for gain, but changing both resistor values is certainly valid as well.

[sean k]

Hey Joe,the easydrives great!
http://www.soundclick.com/bands/1/indigomono_music.htm
 I'll have to try this one out!

[brett]

Hi Joe and all.
Hey Joe (he he), could you tell us what difference the input diode makes?  I presume that it provides some compression.  How much?

Also, these Si fuzz pedals sound better (IMO) with some of the high-frequency whistle and hash taken out.  This is easily achieved by placing a small capacitor (0.047uF or try from .022 to 0.1) in parallel with the 470 ohm resistor.  That makes for rolling off frequencies above about 6kHz.  It makes for a less nasty, slightly vintage sound.

thanks for the inspiration!!

[Fret Wire]

Also, these Si fuzz pedals sound better (IMO) with some of the high-frequency whistle and hash taken out.  This is easily achieved by placing a small capacitor (0.047uF or try from .022 to 0.1) in parallel with the 470 ohm resistor.  That makes for rolling off frequencies above about 6kHz.  It makes for a less nasty, slightly vintage sound.

I was expecting to see a 100pf (or so) cap across Q1 & Q2's collectors. Brett, that cap across the 470ohm gives a pretty good Ge type sound with low gain Si's, right? I usually ran just enough pf across the collectors to kill the real harsh bite, which also depends on the Si's being used. Until I run out of Ge's, I like my Si's to sound like Si's. Sometimes, the classic Si sound is harder to get than the Ge sound. Decent sustain, biting treble without killing dogs, and no oscillations.

I'll have to give Joe's ckt a try.

[brian wenz]

Hello Hello--
     Hey Brett, howare you??
So, if I biased the collector of Q2 to get 4.5 would it sound any different then if I  changed the value of Q1's collector resistor to  get a  4.5  reading off of Q2's collector??
B.

[Fret Wire]

I can answer that one Brian. Yes, I can hear a difference most of the time. Try biasing your next fuzz three ways:

1. Adjusting Q2 only.
2. Adjusting Q1 only.
3. Combo of both.

Especially with Ge's, I find that one biasing method usually sounds better than the other two. Take note of all the voltages each different way. The best sounding biasing will usually have the most uniform voltages.

At least that's what I've found in all my messing around.

[petemoore]

I went ahead and built one, and put it in a box I had.
 High Gain FF circuit, to be certain, and the diode, Si, Ge, or jumper all decidedly sound different.
 I think it can probably use some HF rolloff sometimes, I may use a cap to pot to ground or somethng  like that, so the high end content can be tuned.
 First impression is that the circuit is low noise...HG/LN transistors...go figure !! NTE47 is Q1 and MPSA18 is Q2 in mine.
 I used trimpots for collector resistors, 10k for Q1 and 18k for Q2, set the for shown resistances...wha 'la, biased very nicely...the calcualtions born out in real life...!!!
 Very Cool !!!

[robotboy]

You're the man Joe! I'm about to build your Blackfire, and I thank you for the awesome variety of circuits that you've put online... I'll have to add this sucker to my "list".

[petemoore]

That little diode in there does some magic, I ponder the size of the resistors or the HG/LN transistors role in the Low Noise Floor...the circuit with shown transistors exhibits high gain / low noise. Nice.
 I was doing some A/Bing, like I do, this is one potent FF. Quite the dynamic punch on pick attacks, single notes, it follows that sustain is 'there' as the gain and output are strong.  
 Thanks Again To Joe Davisson !!!  

[brian wenz]

Hell Hello--
      Fretwire-- Thanks.  I've spent some time biasing FF's all those different ways and still haven't come up with any hard-and-fast conclusions as to which way sounds "warmer" or more "GE-like"  etc....
Wotta you think??  
Anybody?
Brian.

[Fret Wire]

Hi Brian, compare the biasing methods to the voltages. See any patterns yet? Q1's emitter is zero, we all agree on that. Q2's collector sounds good between 4.5v and 5.5v. When I get these voltages, I also usually get the best sound:

Q1 base: .1v
Q1 collector: .5v
Q1 emitter: 0v

Q2 base: .5v
Q2 emitter: .4v
Q2 collector: 4.5v - 5v

Btw, this data is with the standard Dallas ckt, not with some of "mods" and "fixes" that some use to make Si's sound like Ge's.

[brian wenz]

Hello Hello--
   Right, I understand the relationship of biasing within the given circuit.  My question is --"Will there be a difference in sound based on WHERE the biasing is done?"    IF I get 5.5v on Q2's collector using Joe's resistor values  [5.6k  for Q1 collector etc....]   and then I switch Q1's collector resistor to 33k and bias Q2's collector to 5.5v  [just for the sake of my question],  will there be a difference in sound?  I think that there will be a difference.....just not sure what it is!
Brian.

[Fret Wire]

My question is --"Will there be a difference in sound based on WHERE the biasing is done?"

Yes, I thought that was what I was saying...sorry for the confusion. But, it's not like better eq or anything like that. It sounds..... better biased. Better sustain, better clean-up with the guitar volume, better touch response and dynamics. Using stable, low leakage trannies of the proper gain, and the best optimum biasing is what gets the best sound. So that's what it sounds like...just optimum biasing for your given set of q's.

[brian wenz]

Hello Hello--
          AH HHaA!!    I always wondered about biasing  from Q1 as opposed to the old tried-and-true  "Q2 collector" method.  [Then there's adjusting the emitter  resistor of Q2..... I remember Joe Gagan talking about his preference for a 2k instead of 1K.]
I keep running into Fuzz Face - type circuits [some of them are English, too]  that have much lower resistor values on the collector of Q1.  Actually, I seem to remember  one called a "SRS Fuzz" that had a 5.6K on Q1's collector.  I'll have to dig up the schematic for that one.
Thanks again--
Brian.

[brian wenz]

Hello Again-
    Wonder what sounds could be had with a lower-gain Q1?
Here I go again.............
B.