Hello everyone!
The last few months I have taken the dive into learning the electronics that went into guitars, amps and pedals. It all started a few months back with my friend telling me I could mod my 76 Bassman and change the circuitry to get the sound of the old Blackface Bassmans from my cheaper CBS made bassman! I ordered the kit, bought a nice soldering station and went to work!
To make a long story short, after a successful blackface mod, and several months of going through articles on this website and Beavis Audio, I started building my own Rams Head Big Muff. It's been going great! I built the Rams head clone and loved the sound that came out of it. After that I wanted to try it with one of the AMZ tone stack mods and I loved that too! Then my friend and several others suggested that I should pack both sounds into the same pedal!
So that is exactly what I did and today I have a fuzz pedal that can switch between the Rams Head Fuzz and this crunchy mid boosted Fuzz. The name? Fuzz Fantasy!
I've run into a problem though. After playing around with the knobs and checking out all of these amazing new sounds I realized the Tone Knob was responding in a weird way. Normally you get the linear 0-25-50-75-100 when turning the knob where 0 has a lot of the bass tone and 100 is a crazy amount of treble. Instead, what I am getting is a 100-75-50-75-100 where both 100's sound exactly the same.
So i should add that I have a DPDT switch that I am pretty sure is the cause of this issue but I am not sure why, and I am not sure what to do to fix it. I will post the schematics as well as my own crude, VERY rough sketch of how I incorporated the DPDT switch into the circuit. Any help getting this fixed or helping me to understand what is going on will be greatly appreciated!
Thank you everyone and I look forward to picking everyone's brains here with future posts!
Original Schematic: http://www.bigmuffpage.com/images/schematics/KR_1975_V2BIG_MUFF_Schem.jpg (http://www.bigmuffpage.com/images/schematics/KR_1975_V2BIG_MUFF_Schem.jpg)
I am using VER 2 of the AMZ Control: http://www.muzique.com/lab/tone3.htm (http://www.muzique.com/lab/tone3.htm)
My rough schematic of the tone stacks + switch + pot: http://imgur.com/uFaPSxL,tQqPqn2 (http://imgur.com/uFaPSxL,tQqPqn2)
All on the breadboard!: http://imgur.com/uFaPSxL,tQqPqn2#1 (http://imgur.com/uFaPSxL,tQqPqn2#1)
Welcome! I'm not sure if this with solve the issue but I think you should switch the connections to the switch of the tone stack shown on the the bottom of your sketch. The bass connection should be on the left side of the switch.
I agree with peterg. The tone stacks are hooked up opposite of each other, so you need to flip one.
Wow I Didn't even notice! Thanks guys! I'll go and fix that really quick and see if it helps.
Edit: Didn't fix the main issue :icon_cry: Tomorrow I may just have to pull it apart and put it back together :-\
What you need is a 3PDT switch to switch not only where you are switching it now (The output of the tone stack), but you have to switch the input of the tone stack as well.
You are getting the resistor/cap to ground on both tone controls at the same time.
You need to switch both the input and output of the tone control to isolate them from each other.
Thanks CodeMonk! I ordered a a 3PDT switch today and it should be here on Wednesday and I will update then. Thanks for the help everyone!
You could have a tone control pot for each variation of tone stack. The dpdt switch could be used to switch between each variation.
Quote from: peterg on February 16, 2015, 07:53:28 PM
You could have a tone control pot for each variation of tone stack. The dpdt switch could be used to switch between each variation.
I wanted to keep everything on the same tone pot because I didn't want to always have one useless knob on the pedal. It is definitely something I considered for awhile but I wanted to keep the pedal as tidy as possible! Thank you for the suggestion though! ;D