November 12, 2019 at 4:41 pm #7449Big OParticipant
I wanted to try using veroboard for building projects that I can’t utilize a GuitarPCB board. I do have a couple of GBOF builds in the works, but right now I have the following circuit on the breadboard and want to make it a useable pedal in the box. It is a fuzz that runs on a AA battery (1.5V). Because of this I can’t use an LED by keeping the circuit simple (no modding a 9V power supply to 1.5V output). I plan to use a simple 2PDT switch since I don’t need to waste a perfectly good 3PDT switch.
Below is the schematic.
My veroboard layout, which is the first I have ever attempted. Any advice and constructive criticism is welcome. Green connections are for my own visulation, helping me tie the components together in my own mind. Black lines are the actual connections to the board.
Wiring diagram for the pedal using a single battery power source. I believe this is correct. If not, please let me know where I screwed up. I am also thinking about using a 1M pulldown resistor in the circuit. I believe I can add this to the input wire from the footswitch and run it to ground.
This fuzz sounds a lot like the Messenger guitar fuzz in that Mark Farner used in the early Grand Funk days.January 18, 2020 at 1:25 pm #9747
Sorry your post was missed due to a web site problem.
Now that we can see your post, I want to thank you for providing such detailed information.
Your circuit is very interesting although I am concerned about using a supply voltage of only 1.5V. If the circuit can be modified to operate on the standard 9V that is used by most pedals, it may have value to the Guitarpcb community.
Of course, the real test is the tone it produces. Is there a way you can send us an audio file that demonstrates its response? If Barry likes the tone, he may be interested in discussing it further.January 18, 2020 at 1:37 pm #9748BarryKeymaster
Yes sorry we missed this. I have been tweaking the forum for weeks now trying to get it setup just right as well as keeping spammers at bay.
Anyway I always was a fan of the Mark tone so I find this interesting. I also share Wilkies concern however my guess is that the circuit is producing a starved fuzz tone similar to what Marks early Red Album sound is. So I think mayeb having a 9 volt circuit with a Voltage Sag added to it might be very worth investigating. Best of both world scenario.
Can you post an audio clip of what you currently have?January 18, 2020 at 3:17 pm #9749CybercowModerator
Interesting build. Look almost like a Sziklai Darlington Transistor Configuration. Or approximating a variant thereof. Cool. Fun circuit!January 18, 2020 at 6:36 pm #9750
Yes, with a NPN and PNP it sure does. I am wondering with a 1.2V supply if the signal is hitting the rails and creating all of the distortion in that manner? So, will a 9V supply work?
Your thoughts?January 19, 2020 at 9:35 am #9759CybercowModerator
Wilikie1 – Yeah, I suspect the lion’s share of the distortion comes from smaller rails – leaving little head-room for signal and providing the signal with a ‘haircut’ under such a low voltage supply condition. (I suspect “sag” by fundamental design rather than an added “starve” pot added to a circuit.)
I’m reasonably sure the circuit will still work with a 9v supply, but I suspect the distortion will not be as emphasized.
The Sziklai pair performs the same basic function of a Darlington pair except that it only requires 0.6v for it to turn on and like the standard Darlington configuration, the current gain is equal to (β1 x β2).
And were we to meet on the street, I would be unable to spell or pronounce “Sziklai” without first looking it up on Google. I just remember the distinct nature of Darlington and Sziklai configurations and count on Google’s ‘auto-correct’ to correct my spelling in the search. 😉January 19, 2020 at 12:33 pm #9764
I think you are spot on, my friend.January 19, 2020 at 9:07 pm #9776BillyModerator
Here’s some discussion on it
And Mark is indeed spot on
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