Help A Noob With Some Bazz Fuss Mods?

[LzeroKI]

Hello, this is my first post on DIYStompboxes, so I apologize if this is in the wrong subforum.

I have lurked on this site (along with a couple others) for a few months while I became interested in building diy pedals. I have learned a lot along the way, and have breadboarded the basic Bazz Fuss circuit (from http://www.home-wrecker.com) and had fun playing with it. I've now decided I'd like to build that circuit again, but with some mods. Before I actually build what I'm planning, I was wondering if anyone on this forum would mind taking a look at the schematic I am thinking of building, and tell me if they see any obvious problems. (I think the schematic is right, but I am no EE, so maybe there are some errors).

What I am planning on, is building the Bazz Fuss v3 (Darlington MPSA13), but adding on a bias control (or maybe trim pot) for the transistor, a voltage starve control, and then tacking on the AMZ BMP tone stack (Tone and Body controls).




I do have a couple questions for you guys about this schem:

1. It would seem like (for the Bazz Fuss circuit) the bias control and the starve control would essentially perform the same task right? (That is to say, they both would reduce the voltage in the circuit; but for the Bazz Fuss, the reduction in voltage would change the transistor's bias).

2. The 0.1uF cap that serves as the "output" cap for the Bazz Fuss portion of the circuit, does it just go on the output of the Bazz Fuss circuit (as pictured)? Or does it belong on the output of the whole circuit (in between the "Tone" and "Volume" controls)?


Thanks for any help you guys can provide, I have a technical backround, but I am still new to DIY Pedals/circuit design.

[superferrite]

You might just have to stick with the LED--it's the loudest but least distorted-- depending on the amount of signal that tone stack robs.  Or you could put a lil' boost on the end (look up the Big Muff's follower stage).   
Seems that the "starve" would just make it splatty.  I usually just stick a 10K in there or use a trimmer till it sounds focused.  It doesn't sag nice like Fuzz Faces do, in my opinion.

[RandomGlitch]

I found a bias control is useful, mine used a 100k pot. I think its useful on bass. Dont know what you are building it for, guitar or bass.

For caps, I found too large values tended to make it farty.  I favor 0.1 - 1uF, and the boost the bass after. The BMP tonestack will do that.

For bass I prefer the 2N3904 or 2N2222, over the smoother more high gain MPSA13.

all that said, you have to experiment for what works best for you and your set up.


Good luck

[LzeroKI]

You might just have to stick with the LED--it's the loudest but least distorted-- depending on the amount of signal that tone stack robs.  Or you could put a lil' boost on the end (look up the Big Muff's follower stage).

So, could I just throw an LPB circuit in between the "Bazz Fuss" half of the circuit and the "BMP Tone Stack" half of the circuit?

I found a bias control is useful, mine used a 100k pot. I think its useful on bass. Dont know what you are building it for, guitar or bass.

For caps, I found too large values tended to make it farty.  I favor 0.1 - 1uF, and the boost the bass after. The BMP tonestack will do that.

I am a bass player first and foremost, but I mess around on 6 string guitar as well. Ideally this fuzz pedal would be useable for bass and guitar.  My thoughts are to have a couple different input caps on a switch or pot, so I could go between a higher cap (for bass) and a lower cap (for guitar).

For bass I prefer the 2N3904 or 2N2222, over the smoother more high gain MPSA13.

Is there a way to put transistors on a switch? Or would this cause problems with the biasing of a MPSA13 vs a 2n2222 or 2n3904?


Thanks for your help guys, I am still somewhat new to DIY Effects.  I'd appreciate any advice anyone else can provide as well.

[ubersam]

So, could I just throw an LPB circuit in between the "Bazz Fuss" half of the circuit and the "BMP Tone Stack" half of the circuit?

I'd put the recovery stage after the tone stack. You'll lose as much as 10db through the tone stack so you'd want a way to bring the level back up. The LPB will add its own character to the overall sound so that wouldn't be my first choice for a recovery stage. I'd pick something cleaner, so to speak. Something like an opamp booster with a gain of 10. Then again, Bazz Fuss into an LPB might sound good.

[RandomGlitch]

Just to clarify: small cap values for guitar, say 10-100nF, bu higher is ok too.

For bass anything from 100nF to the published 10uF.  I've heard of people using 20uF but dont think higher vales make massive difference. In fact I think they can make it worse, more farty.

The bazz fuss with Lpb and BMP tonestack has been dIone by myself and others many times and works well.

I adjusted the emiiter resistor to 1.5k for a more cintrolable level.

you can switch between resistors with a SPDT switch, just switch one leg of each. The other two are permanantly connected. The bias gives you all the adjustment you then need to compensate for their differences.