Author Topic: Bazz Fuss tone pot problem  (Read 122 times)

CCS

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Bazz Fuss tone pot problem
« on: July 14, 2017, 01:00:02 AM »
Hi All I asked this question a while ago and I got replies thanks. I tried to implement the cap blend tone control
without success. I'm not too clued up with schematics. I'm at breadboard stage, and won't commit to perf board until sorted.
This is exactly what I've built (I've added a volume control, not shown) My end result is no change to tone which ever way I turn
pot. I'm obviously doing something wrong for it not to work, it's doing my head in, please help. Thanks Paul   

Matmosphere

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Re: Bazz Fuss tone pot problem
« Reply #1 on: July 14, 2017, 06:22:58 AM »
Nice the Bazz Fuzz is a great circuit. There's an excellent write up on the bazz Fuzz over at Tonefiend.com that might help you out.

midwayfair

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Re: Bazz Fuss tone pot problem
« Reply #2 on: July 14, 2017, 10:06:45 AM »
Check your cap values against a known-good version of the schematic with a similar tone control.

http://home-wrecker.com/bazz.html

tl;dr: No TLDR! Read the article!

If you lifted your tone control from another pedal (perhaps a fuzz face, which is what it looks like), your lesson for today is that you have to consider the entire R-C network in a resistor-capacitor filter, and that you can't just lift the capacitors out of a circuit and expect them to affect the same freequencies. Your cutoff frequency is determined by 2* Pi * Resistance * Capacitance. It's hard to see what the resistance is in this device, but if you don't want to figure it out abstractly (and you probably don't, since a diode won't work exactly like a resistor, and you also would have to take the characteristics of the transistor into account), you can always measure with your multimeter to ground and +9V, then calculate the readings in parallel, to get a decent idea. There are online calculators to help with this until you get better at eyeballing it.
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CCS

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Re: Bazz Fuss tone pot problem
« Reply #3 on: July 16, 2017, 05:13:41 AM »
Thanks for your reply. I'll dig deeper

impycat1

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Re: Bazz Fuss tone pot problem
« Reply #4 on: July 16, 2017, 05:43:43 AM »
Try B100k for Tone pot. Pot 1 and IN to C1. Pot to to C2. Leave Pot 3 unconnected

midwayfair

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Re: Bazz Fuss tone pot problem
« Reply #5 on: July 16, 2017, 08:31:57 AM »
Try B100k for Tone pot. Pot 1 and IN to C1. Pot to to C2. Leave Pot 3 unconnected

This is what his schematic already does but you've suggested a pot value that's strictly worse.
Myself's music & things I make: http://jonpattonmusic.com. My band: http://midwayfair.org. PCBs of my designs from: http://www.1776Effects.com (Bearhug Comp & Cardinal Harmonic Trem); http://www.jmkpcbs.com (Hamlet+ delay & Blue Warbler envelope vibe); Snow Day OD/Flabulanche: www.madbeanpedals.com

WormBoy

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Re: Bazz Fuss tone pot problem
« Reply #6 on: July 16, 2017, 08:40:51 AM »
Try the cap values from the home-wrecker page, that should be a good place to start experimenting. My guess is that the difference in the two cap values needs to be much larger to get a good (and audible) range in tone.

Oh, and smart to start with the breadboard  ;).