Friday, May 11, 2018
KMA Fuzzly Bear
For Fuzz Friday, here's an interesting take on the Bosstone fuzz with a few value changes, extra diodes, and a voltage sag control. Schematic and discussion here. I did add a bit of a mod to this–the resistor marked "0-10k" limits the minimum setting of the drive pot. Stock, lug 1 goes directly to ground. But IMO, it's a bit better to have that limiter there, otherwise it's just another way to mute the pedal. So adjust that to taste.
Nice compact layout! I'm the guy who drew up the strip board at the link and settled on 4.7k as a min. resistor, letting me get usable tones at lowest gain. Of course, experiment. One guy who built it reported getting octave type sounds with his neck pickup, low gain and high sag.
ReplyDeleteOh that's cool. Don't think I've gotten octave out of my Boss Tone before.
DeleteI actually referenced your stripboard layout in drawing this one up and liked the min resistor addition. I'm generally not a fan of gain controls that can just turn off the effect. Thanks for chiming in!
I built this one, but it sounds bad...Probably something I have goofed up somewhere, or a bad component. I used 5089's for transistors. I'll go back over it sometime later and see what I messed up.
ReplyDeletebuilt this again, from scratch. same result. Used BC109 and 2n3904 this time.
ReplyDeleteThe really weird thing is there is a tiny (I mean TINY) sweet spot in the sag control that will send some signal thru...Like if the sag control was a 5K instead of a 50k...I actually took the sag pot out and jumped a small resistor (1k-4.7k) in there and could get some sound out. Still sounded bad, but at least it sounded like something. lol. I dunno...If I get some time I might do Alex's vero layout, but I'm trying to get my hammond skx to run thru my leslie 147 atm, so...I should really just get a life :;
DeleteQ2 needs to be a PNP transistor. Probably why its not working.
Deleteany PNP? I'll see if I have any. Any suggestions? Obviously, I know nothing about electronics....But I can solder like a beast.
DeleteI am so embarrassed. I thought 3904 was close enough to 3906...But the 04 is NPN and the 06 is PNP....Guess what I found when I dumped out my whole bin of transistors...3906's. Tag it as verified. Apparently I have an extra one already made up if someone needs it. Thanks for the heads up, Dave.
DeleteHaha it happens to the best of us. Thanks for verifying Peter!
DeleteHopefully my dumb-assed-ness will save someone else some heartache. Thanks again for the help today, and all of your great layouts!
DeleteGreat Fuzz. But I use B150K as Sag
ReplyDeleteBuilt it, the only thing that came trough the amp was a very weak signal very distorted, changed the diodes and the transistors and again the same result.
ReplyDeleteMine works nicely but I feel it sounds a bit thin. At least it's not as fat sounding as in the demo videos, so I'm wondering what hfe values you guys used...? I have a BC109C and a 2N3906. The BC has quite high hfe (around 480) and the 2n3906 has something around 150 I think. And I've used a 220n input cap instead of the 330n, but calculating the cut-off frequency of the HP-filter it forms with the 150k to GND, the 220n should be totally sufficient (4.8Hz with 220n vs 3.4Hz with 330n).
ReplyDeleteAlso the sag-control doesn't change too much in the sound.
So maybe it's just about the transistor hfes?
Thanks for the layout btw! Great stuff.
Hello. First of all great site. This will be my first build using your shemes. I was not able to find the image for this one on the image transfer library. Could you tell me how it should be scalled to fit the desired size? Thak you very much.
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ReplyDeleteHey just discovering your amazing work, really appreciate you share it with everybody.
ReplyDeleteWell just found the caline fuzzy bear, I think is a copy of this, my question is with this layout, maybe can I modify too the fuzzy bear?
made it today!Sag should be 50k, Q1 i took bc550c, hfe=450, Q2 i took 3906, hfe 170-200. I tried Q2 germanium mp42b - this is another fuzz! I tried Q2 hfe =300,400 - it's too much. So better 3906, sound like demos!
ReplyDeleteDelicious, fat as f*ck fuzz. Just finished mine. Thanks a bunch for this one! Goes from thick meaty fuzz to kind of more distortion like tones with a bit of gain on your amp. I think I have a new favorite pedal.
ReplyDeleteIs there any other value I can use instead of the 330nf capacitor?
ReplyDeleteProbably too late for you, but in case anyone else comes across this... THe 330nF seems absurdly high. 47n should be fine. Or 100n
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ReplyDeleteI built the pedal but it only gives me a clean signal, will you know why it happens
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