Where to place my gain control in the circuit

[plichtenauer]

I have just started building pedals recently, and have put together a distortion circuit that sounds pretty decent. My only issues are that I cant figure out where to put the gain control in the circuit and how to get more sustain out of the circuit. Its almost like it gates itself as the sound starts to drop in volume. Im using a 4401 and 2222 transistor with a 1n4001 and 1n4004 diode on them. Ill post a pic of the breadboarded circuit when I get a chance, but any quick advice will help out a ton.

Thanks!

[petemoore]

 Schematic or general description of the circuit would help...
The guitar volume control is one way to tell, but sustain is probably best with this all the way up.
Usually sustain is increased...er I don't know the subject matter well enough to say that.

[midwayfair]

It's impossible to say without a schematic.

The only general answer is "where it will do precisely what you want it to."

Your description makes it sound like your transistors aren't biased properly. Do that before adding a gain control of any kind.

[nocentelli]

Double bazz fuss? It gates, not much you can do. A schematic would help suggest where a gain pot could go: If it IS based on the bazz fuss, a small pot (1k/2k/5k) from emitter to ground will reduce the gain, but it usually sounds best running at maximum.

[plichtenauer]

Yeah, its is based off of the bazz fuss, but I put in a second stage. I also doubled up on the diodes on each transistor. That seemed to give me more sustain before it gated. I think I'll forgo the gain pot and keep it sounding mean as hell.

[nocentelli]

A pair of LEDs also sounds pretty good, quite loud and aggressive: You could always use a switch to flip between the two options instead of a gain pot to provide some variation.

[plichtenauer]

Heres a link to see the circuit as it sits on the breadboard.

https://www.dropbox.com/s/fumsskku0nm09lm/IMG_20140902_124802_434.jpg?dl=0

I'll have to look into the switch idea. I like that.

[mth5044]

A picture of your breadboard isn't going to help at all, especially from the side. Perhaps this is the chance to learn how to draw schematics?

[plichtenauer]

That's what I have been working on learning lately.

[plichtenauer]

Alright, let's try this. Bear in mind that this is my first ever attempt at drawing a schematic and I most likely have some stuff messed up. Please let me know if you see something that is wrong on there.

https://www.dropbox.com/s/2rdv09m45kd51ae/IMG_20140902_145625_991.jpg?dl=0

[pappasmurfsharem]

Alright, let's try this. Bear in mind that this is my first ever attempt at drawing a schematic and I most likely have some stuff messed up. Please let me know if you see something that is wrong on there.

https://www.dropbox.com/s/2rdv09m45kd51ae/IMG_20140902_145625_991.jpg?dl=0

Two options you could try.

You could Run

• J1 to Lug3 of something like a 1Meg
• Lug 2 to 1st point on C1
• Lug 1 to GND

This would act similar to your guitar volume control.

OR

Break the connection between R2 and C5 or Remove R2 entirely since I would assume this is just limitting the signal hitting Q2 anyway.

• Run from R2 (or if R2 is removed from C2) to Lug 3 of some value pot
• Lug 2 to C5
• Lug 1 to GND

This would let the full guitar signal clip at the Q1 stage, then you could Minimize the clipping of the Q2 stage by controlling the volume of signal hitting Q2

There is probably some fancier way to do this as well but those would work to some extent, you might have to play with the POT values.


deadastronaut has something that looks somewhat similar to your schematic here. http://www.diystompboxes.com/smfforum/index.php?topic=106498.0

[Ben N]

Boosting the input of a Bazz Fuss de-gates it. Take a look at the ROG Whisker Biscuit. Putting in a sustain control between the first and second stages should be interesting too.
Edit: Should have noted that my BF experience was with the Darlington version, boosted with Gus's original NPN boost aka the forum boost.

[samhay]

https://www.dropbox.com/s/2rdv09m45kd51ae/IMG_20140902_145625_991.jpg?dl=0

The schematic looks good, but it would be useful to show component values.

Two more options you could try.

- Make R2 a variable resistance - hard to predict how useful this will be seeing as you do not have feedback resistor around Q2.

- Replace R1 with a pot of the same value (10k, 100k?) - lug 1 to V+, lug 2 to C2 and lug 3 to Q1 collector.

Edit - as drawn, C2 is redundant.

[midwayfair]

Use the Darlington transistor version of the Bazz Fuss. It won't gate as much. Everything else you can do to the circuit with those two transistors won't solve the basic problem that they simply can't produce enough gain.

[plichtenauer]

Awesome information everybody! Thank you for all of your help. I have decided to leave a gain control out of the circuit and just have it scream at its full stoner metal glory. I have found that I get some interesting tones when I turn down the volume on my pickups.

The choice of transistors and other parts simply cam down to what I had on hand. Overall it was pretty awesome just to have the circuit operational. I like the small wins as I learn. Next up is getting it on a board and mounting it up in a box.