8 Bit Fuzz anyone?

[Canucker]

http://www.paulinthelab.com/2012/11/8-bit-guitar-fuzz-ii-effect-stripboard.html anyone ever build one of these? The poster is requesting mods but nobody responded to that...I'm thinking volume would be a good one for starters.

[Canucker]

[Devius]

I built the heliotrope from sabrotone with mixed results. To be honest I think it functions properly but it has sweet spots. I want to rip the fuzz out of it and just get the 8 bit sound. The carrier frequency constant whine is unfortunate but I did notice its not as prominent with no fuzzy gain. The Malekko Bit is, from my research, what sort of sound I'm after.

[pinkjimiphoton]

paul (insonicbloom)'s fuzzes are great. he really knows his shit with the diy, he had one of the first klons on vero.
i've got this on my list to build, but to me it sounds very similar to the nintendetar/pong war machine/pwm pedal. not something i have a ton of use for every day, but
then i'm fairly addicted.


as for a volume control, he didn't add one cuz he didn't think it was necessary to add to the layout. take the output to pin 3 of a 100k pot, take the output from the wiper, ground the other pin. done.

as for mods, i'd probably try an n-channel mosfet instead of the 3904, use germanium for the diode clipper to warm it up a little, and use a decent opamp instead of a bloody 741.

i have a feeling a pre-tone control like on one of my designs (@#$%, i can't remember which one at the moment!!!) would probably help a bit...just wire say, a 10k pot in parallel with the input, take a .022 cap from wiper to ground...kinda like using a tone control on a guitar, just to roll some of the highs off a bit on the way in...make it "smoother".

finally, definitely, add a "sag" control so it would do bad, bad things.

[Canucker]

whats wrong with a 741? What would you use in its place? I pretty much just build stuff as I'm told at this point. 

[garcho]

whats wrong with a 741?

There are many threads here that are full of opinions and even some facts about the differences between op amp ICs. 
For the most part, schematics list the IC, otherwise start with a TL072 or a 4558, if all it calls for is an op amp. If you don't have those, try whatever you have first (check the pinout), then order something else.
In the case of the LM741, they're kind of noisy power guzzlers, but if it's all you got, don't sweat it. It's a single op amp, so try a TL071 as a pin-for-pin replacement first. There's the OPA134 if you're feeling fancy. Sometimes the cheapest/easiest/best thing to do is simply use half of a dual op amp IC that you bought in bulk. Try half of a TL072, LM833, 4558 or a NE5532. FET op amps, like the TL07x series, have higher input impedance, and might not always be interchangeable with BJT op amps, like LM833 et al.

Here's Mark Hammer's take on some standard op amp ICs.

NE5532 or LM833: Essentially interchangeable and generally appreciated for low noise under certain circumstances; handle low-impedance output loads (like reverb springs, or headphones) very nicely.  Draws more current in some uses.

TL071/2/4: Ubiquitous.  More than enough slew rate for all applications.  High input impedance and low noise.

LM324: A standard in the world of quad op-amps.  A real workhorse.  Essentially a pair of 4558s in one package.

4558: Made by a bazillion manufacturers, and found under the hood in a large proportion of commercial pedals.  In many applications, merely good enough to do the job, and in other(select) applications a key element to tone.

1458:  Not a great op-amp by any stretch, by essential to the workings of several classic pedals.

Here's a quote from R.G.

Is there a BEST OP-AMP? Lower noise vs lower consumption? FET vs

No.

[anchovie]

use a decent opamp instead of a bloody 741.

I'd recommend this in a lot of situations, but for something called "8 Bit Fuzz" I'm not sure that audio fidelity is an issue! 

[EATyourGuitar]

from all the threads I have read on the 741, it seems that the 741 is just more noise and therefor makes your signal to noise ratio worse. what I would like to know is if this affects the noise floor when no audio is being passed.

on the subject of low noise opamps, every opamp that claims to be low noise is actually just low noise for its intended purpose. if you take some expensive OPA and start doing things it was not designed to do, you will probably have more noise than if you selected the right opamp for the job.

[pinkjimiphoton]

yah, my only issue with a 741 is the noise/hiss. it's there and noticeable when you stop playing.

other than that, it sounds fine. you can always add a cap as a low pass filiter to ground to try and eliminate it, but if you go far enough to cut the broadband of the noise, it'll be well into noticeable guitar frequency territory, at least IMHO.

[Canucker]

I can't believe how many stupid mistakes I made in making this. Its to late at night to give it a good test though now that it works. Not sure why the variable resistor is used cus you really have to tune it in to get it to work...a hair to the left or right and you get no sound....maybe once I crank it in the daytime hours.

[pinkjimiphoton]

it's just there to help bias it.. i think. you'll probably find it more useful when the thing's loud, then you can play with it a bit more. may be just so you can use different oa's or something. did ya try asking paul?

[petey twofinger]

i missed this circuit when i was at his page , looks interesting , drools .

sag :

http://www.beavisaudio.com/projects/DBS/

pmed as well , thanks canuker !

[Canucker]

I added the volume control to this so thanks for the heads on how to do that. The little practice amp I have needs a new volume pot cus its can't quite be turned down all the way...its an odd cheapy style pot and things are crammed in there so the pots I have won't fit.... At louder volumes the bias does a bit in regards to note sustain. Still not a great deal. Over all it seems like a more complex version of this   It sounds a little cooler yet without a fuzz control its pretty limiting. When your not playing its DEAD silent so the chip isn't an issue. I had some issue with my thing-a-ma-bob build that still hasn't been figured out...(extra noise beyond a certain fuzz setting that no other builders I talked to suffered from...bad chip I suppose). Some tone control would be nice. I find with this kind of effect things get pretty trebley. I'll try it out with my eq pedal and figure out something decent.
Overall I'm really happy I found and built this. Not that it will see tons of use but its a "very me" kinda sound.

[Canucker]

i missed this circuit when i was at his page , looks interesting , drools .

sag :

http://www.beavisaudio.com/projects/DBS/

pmed as well , thanks canuker !

Installed the "sag". It doesn't do to much unless you "fully" sag....I guess that a greater amount of resistance is required to get something saggier. I used the 10K pot as shown. Time to change things up.

[petey twofinger]

try adding a 5 k or so to that pot in series , but you may need a switch ...

[rocinante]

Canucker. I tried to build this last week and got nothing. Is it really a fine line when tuning in that 47k trimmer?(I had to improvise with a 50k pot) It seemed my circuit was working, but I couldn't get any signal...maybe I need to try again but I checked so many times I eventually gave up... 

Any tips or anything to get it going?? Or working Vs??  And just quickly- is it really 9v going directly into pin 7? Or am I reading the schem wrong??

Merry Xmas,
Steve

[Canucker]

Canucker. I tried to build this last week and got nothing. Is it really a fine line when tuning in that 47k trimmer?(I had to improvise with a 50k pot) It seemed my circuit was working, but I couldn't get any signal...maybe I need to try again but I checked so many times I eventually gave up... 

Any tips or anything to get it going?? Or working Vs??  And just quickly- is it really 9v going directly into pin 7? Or am I reading the schem wrong??

Merry Xmas,
Steve

I used a 50K pot as well and you really REALLY have to dial it in....once you get it, a fraction in either direction and you get no signal when your at low volumes....at higher volumes its more forgiving I guess you'd call it. Yup the 9volt goes to pin 7 on the IC..... I bet once you tune that pot you'll have it running....cus if I can get it going then anyone around here can!

[Canucker]

try adding a 5 k or so to that pot in series , but you may need a switch ...

I figured i'd "go big or go home" on this...I went with a 47K resistor!!! I might go even higher just to make the most annoying sounding effect ever!!!...well maybe not ever but it sure would turn some heads.

[rocinante]

I used a 50K pot as well and you really REALLY have to dial it in....once you get it, a fraction in either direction and you get no signal when your at low volumes....at higher volumes its more forgiving I guess you'd call it. Yup the 9volt goes to pin 7 on the IC..... I bet once you tune that pot you'll have it running....cus if I can get it going then anyone around here can!

Thanks. I might give it another go next week when I get back home. But I just found it a bit frustrating and the schematic confusing- I wasn't sure if I was reading it right. But anyhoooo. Thanks and have a good Xmas!!

[Canucker]

umm something is missing from that last post?