Knight Fuzz build report

[LucifersTrip]

Ever since I dug out my bookmarked schematic for Mark Hammer, I've had a craving to finally build this vintage "fuzz"...
http://www.diystompboxes.com/smfforum/index.php?topic=99037.msg868429#msg868429



Unfortunately, for my taste, the stock version is a very average pedal that is somewhere between a distortion and fuzz and it pretty muddy with not much balls at all.

So, this build report will be re-titled "How I turned a mediocre distortion into a killer fuzz!!!"

1) Diodes: Firstly, I have to believe they're silicon. With any germanium I tried, the signal is way too low & flat. Also, do not dismiss this as one of those "any silicon will be good" circuits. I went thru a bunch of pairs, most sounding a little different, until I decided on one that beat the others. Fwd voltage ~ .7V

2) Transistors: I started with vintage button style with hfe ~300. This put the collector voltages at ~ 1.6V. This gives a distortion/overdrive at low attack setting and a  sagging, slightly farty tone with attack at  full. Lowering the resistors on the collectors to bring the voltages to ~ 2.5- 4V made it a bit hotter and smoothened it out. Not great, but better.  You might think that using higher gains for this might get rid of some muddy-ness and make it spark, but that'll just put  a lower voltage on the collectors and you'll just have to lower the collector resistors even more to hit the 2.5 - 4V sweet spot. Ie, a 2N5088 put Q2C ~ 1.2 - 1.3V.

Since this was designed with 100K collector resistors and the sweet spot was 2.5 - 4V, I think it makes sense that the original transistors probably had lower hfe's. I put 2 vintage button style 2N2222's in there with hfe's ~ 80-90, both collector voltages hit 3.5 - 4V and there was a quick improvement with no adjusting of resistors....back to this later.

3) A .0015uF cap across Q2 BC?  Is it really necessary to use a cap that large to tame it that much? No. Without it, there's a load of sizzle, but that large size is not needed. So, I started low with a 50pf and worked my way up until all sizzle was gone. Final result, 220pf and the pedal is now even hotter, of course.

4) Mud: This thing really is too muddy to really fuzz or scream, so I lowered the three .05's to .022. Big, big difference and now this thing is finally getting close to being boxable

5) Input fuzz killer: Is it really necessary to have a 470K up front to tame it even further. If you get rid of it, you'll wind up with too much harshness when the  attack is full on, so I inserted a 500K pot and worked my way up from 0K until the harshness ended. End result is a 50K and the pedal is again, much hotter and I was almost ready to box, when....

6) Germanium is king again: Taking a hint from the Fuzzrite Q2 and knowing this type of topology can work with germanium with little work, I subbed a ge into Q2...and it was night & day right off! (the same way a germanium Fuzzrite absolutely destroys a silicon one). Finally, a real fuzz with some nice saturation and sustain

Next: tweak the collector resistor for best sound. This actually sounds excellent from 1V - 4V (~60K - 8.2K) on Q2C, so I went with an 8.2K with 50K pot. The biggest difference is that there's more high end at 1V.

7) back to #5. There is no longer a need for the 50K since germanium is not as harsh. Now I can turn it up to full with nothing slowing me down at the input

At this point, it's a killer fuzz, with nice saturation, excellent sustain....but it can always be made better.

8): The 2.2M on Q2. A germanium probably won't work the best with the same BC resistor as a silicon. Again, look at the 1M on the Fuzzrite's Q2. Sub a 1M pot there, start at 0K and turn till you get the hottest, smoothest, richest tone. For me that was ~ 500 - 600K

I think that should do...from crap to fuzz in 8 easy steps.

Final schematic with details & voltages:

[rutabaga bob]

Nice!  Now...where are some sound clips?   

[pinkjimiphoton]

lucifer...the patron saint of lost fuzzy goodness!!

clips!! 

i can't wait to hear it... you demon, now there's ANOTHER one on the build list.

only about 100 ahead of it..unless i like your demo! 

[John Lyons]

Very cool. I liked seeing the progress and notes. Fun stuff!

John

[Mark Hammer]

Interesting.

I was more or less content with mine using the stock schematic, but that was very much a result of a search to have a bunch of fuzzes that were different from each other in stock form.  It's not the greatest fuzz, but it IS different sounding from the others.  Perhaps it is the muddiness that does that.

The only thing I think I changed was replacing the 470k+100k pot wit a 330k and a 250k pot, so that I could provide a less attenuated input signal to the circuit for a little more range in distortion intensity.

One of the things I guess one has to keep in mind when building units like this is to have a sense of what the typical pickup encountered would be.  I'm thinking something like the ceramic mag on a soft steel base single-coils like on my Kent or found on so many other import guitars.  Or perhaps the Danelectro-type single coils.  It would be the rare case where someone had hot alnico single coils or humbuckers.  Perhaps circuits like this one sounded better on those sorts of guitars.

Once I have my dozen-fuzz rack unit wired up so that I can just rotate a switch and compare different fuzzes instantly, I may just have the same epiphany as you...and I'll be glad to come back here and find the experiments you did.  Thanks. 

[pinkjimiphoton]

+1 on the old pickups...

my original tiesco del ray sounded great thru my kay fuzztone..
when i played the tele, and later the les paul i really cut my teeth on, i hated it...so let it go to the sands of time.
i've done 3 different versions of the kay, and none of 'em even sounds close to the sound of them low-gain single coils hitting them low-gain transistors.

[LucifersTrip]

Well, hope someone will take a shot and add another fuzz into the world...

Regarding sounds, I actually packed away all my recording stuff a while ago...and have been too busy building and playing without recording.
The video for the Turkey Shoot will be an even bigger pain since I have nothing to give me anything with good sound. I'll wind up bringing the pedal and amp over to a friend's.

Oh, I realized that #6 should be "The biggest difference is that there's more high end at 1V", not vice versa...I edited it and flipped the 50K pot....not a big deal.

edit:
I forgot to mention that the Q2C sweet spot for me with the ge was no longer 3.5 - 4V, but lower at 1.5 - 2.5V, so the 50K pot/8.2K R puts that at around 12 o 'clock

I also revisited #3 thinking I could get away with decreasing the 220pf since I used a ge Q2, but no luck, so 220pf remains.

[midwayfair]

nice ... Really impressed by just how systematic you were in identifying and curing each issue along the way. Makes a good template for future experiments. Mentally bookmarked this

[Mark Hammer]

+1 on the old pickups...

my original tiesco del ray sounded great thru my kay fuzztone..
when i played the tele, and later the les paul i really cut my teeth on, i hated it...so let it go to the sands of time.
i've done 3 different versions of the kay, and none of 'em even sounds close to the sound of them low-gain single coils hitting them low-gain transistors.

We too easily forget that what was likely to be fed into both pedals and amps has changed over time.  My attention was first drawn to this well over 30 years backs in a Guitar Player article, where possibly Jeff Baxter, or one of the other columnists, noted that some of the affinity for "vintage" amps at that time (the late 70's) was because older amps were designed in anticipation of lower output pickups, and by the late 70's pickups had generally become much hotter, thus more easily overdriving those older amps and delivering a more pleasing tone to the user than, say, the solid-state and "improved" tube amps of the late 60's and early 70's.

My attention was also drawn to this again, via a thread here some years ago regarding the fuzz used on the Wilson Pickett tune "Engine #9", and the difficulty members were having in nailing that tone.  What I reminded them at that time was that a lot of early soul/funk hits were cut with session musicians, who would often come in with big jazz boxes.  An ES-175 into a fuzz sounds different than a Les Paul into the same fuzz, even though they may both sport the same pair of humbuckers.  A floating wooden bridge will do that.

[pinkjimiphoton]

+1 

or is that +2?

[pinkjimiphoton]

weird, the pic wasn't showing (at least here) so i re-posted (hope you don't mind, dave)

[LucifersTrip]

weird, the pic wasn't showing (at least here) so i re-posted (hope you don't mind, dave)

my hosting site might've gone down when you checked since it's there now...but no prob, you can post, re-post, save, edit, etc to any pic I post.

[pinkjimiphoton]

and back atcha bro

[snk]

Lucifer Trip, thank you for all the insight about all your mods and improvements.
I just discovered about this FUZZ, and i like its original sloped vintage enclosure, so i am considering building one, just to fit it into a nice enclosure too

4) Mud: This thing really is too muddy to really fuzz or scream, so I lowered the three .05's to .022. Big, big difference and now this thing is finally getting close to being boxable

Out of curiosity, am i right assuming that doing the #4 mod (reducing cap values) may lead to decreasing bass ?
I am planning to use it on synths (no guitar), and i wouldn't like a too thin-sounding fuzz. Do you think this circuit, with your mods, could bring me into a bass friendly ballpark, with bite and low end (I didn't like the Mosrite i built last year, but i like my Shin-Ei Fuzz Wah, if that gives a hint)?
Or maybe this is not the right application for this fuzz ?

[pinkjimiphoton]

.022 should be fine. its reducing bass, yes, but in the case of a fuzz, fuzzing too much of the low end just makes the fuzz sound gated and weak. the mods dave did will shift it upwards about an octave, but still be fine for a bass even at 22n. worst case, build it with a fake variable cap, or breadboard til you're happy.
lucifer's been mia for a long time. sucks, he was THE fuzzbox guy

[snk]

Thank you, PinkJimi.
This is what i had guessed (feeding it less bass to avoid loading it too much), but i wasn't sure. Now, i really want to build it, ah ah !
Did you build it, yourself, do you enjoy it ?

[pinkjimiphoton]

yes, i DID build it years ago, it wasn't my fav fuzztone, but it was pretty cool bro.
breadboard it first. breadboards can be a pain in the ass, ya gotta wiggle stuff around sometimes to get good connections,
but man, way easier and cheaper than the way i used to do it, which was build stuff on vero THEN mess with it

[Mark Hammer]

I boxed one up.  I find it to be a perfectly acceptable distortion/fuzz.  Does it sound like a contemporary noisemaker, ideally suited to heavy metal?  Nah.  Not a chance.  Accept it on its own terms, and find a use for the sounds it does make.

[snk]

Thank you for the feedback, both of you.

build stuff on vero THEN mess with it

This is indeed what i do
I need to learn how to mess around with breadboards.

[pinkjimiphoton]

Thank you for the feedback, both of you.

build stuff on vero THEN mess with it

This is indeed what i do
I need to learn how to mess around with breadboards.

you really do. you can waste thousands of dollars and hours trying to debug a bad vero layout only to find ya need to bin it. the traces lift, the boards warp, all kindsa stuff.

but ya can learn a lot more by f'n up than doing it RIGHT sometimes. so... rock on bro!