I'm slowly building a very basic distortion pedal from the ground up, trying to learn some basic electronics as I go. I'm a programmer by trade, so my electronics skill level compared to learning how to bake, is like knowing where the kitchen is.
I have a basic gain stage as shown in the diagram, with a gain of 11 and a power supply of +9V DC. I verified the input signal from my guitar and the output signal from the op amp (TL082) using my oscilloscope. The input from my guitar is about 250mV p2p and the output signal is boosted as expected. I didn't configure enough gain to distort the signal but I will do that later (and add transistors to clip the output) once I'm happy with a basic boost stage.
I plugged the output into my small Peavey practice amp's clean channel and set the volume to around 2. When I played my guitar, I could hear the signal through the Peavey, but the signal broke up when the guitar volume knob was set turned up. I guess it was overloading the amp and it sounded terrible, but not distorted. Perhaps the bass frequencies are too strong. I will learn how to add tone control in a bit.
Do I need a resistor on the output, after the capacitor to lower the amplitude? Is there a max voltage the output should be, say less than 1V? I only have a 10k potentiometer (need to order some) so I could put that at the output to control the volume. Is this the correct way to go or is there something fundamental I'm missing? I'm not even sure I'm asking the right questions here.
I've looked at some schematics for existing pedals and they have a volume pot at the end of the tone stage or output buffer. This is definitely something I can add. Any help is appreciated. Thanks
(PS I didn't create the attached diagram, but I somehow managed to build the same circuit. I'm using this diagram as I'm having trouble creating a schematic that correctly shows the +ve/-ve inputs to the op amp).
I have a basic gain stage as shown in the diagram, with a gain of 11 and a power supply of +9V DC. I verified the input signal from my guitar and the output signal from the op amp (TL082) using my oscilloscope. The input from my guitar is about 250mV p2p and the output signal is boosted as expected. I didn't configure enough gain to distort the signal but I will do that later (and add transistors to clip the output) once I'm happy with a basic boost stage.
I plugged the output into my small Peavey practice amp's clean channel and set the volume to around 2. When I played my guitar, I could hear the signal through the Peavey, but the signal broke up when the guitar volume knob was set turned up. I guess it was overloading the amp and it sounded terrible, but not distorted. Perhaps the bass frequencies are too strong. I will learn how to add tone control in a bit.
Do I need a resistor on the output, after the capacitor to lower the amplitude? Is there a max voltage the output should be, say less than 1V? I only have a 10k potentiometer (need to order some) so I could put that at the output to control the volume. Is this the correct way to go or is there something fundamental I'm missing? I'm not even sure I'm asking the right questions here.
I've looked at some schematics for existing pedals and they have a volume pot at the end of the tone stage or output buffer. This is definitely something I can add. Any help is appreciated. Thanks
(PS I didn't create the attached diagram, but I somehow managed to build the same circuit. I'm using this diagram as I'm having trouble creating a schematic that correctly shows the +ve/-ve inputs to the op amp).
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