I am pretty new to this so I am as confused as you are as why R15 is there. I found this circuit in an old book somewhere on the internet and tried making it work. As you can see the tone control part has 0V all over it and the output is 0 as well. The simulation:Hi lwt,
Please explain in what way it does not work.?
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What is the purpose of R15.?
It is not my design. I am pretty new to this and I don't think I would be able to design something similar from scratch.Is this your design? If so, walk through the stages and describe what each is supposed to do and how it is actually behaving compared to what was intended.
If not, then it's even more important and valuable that you do this.
Would polarized capacitors solve that problem? I think in the original circuit that's what they usedhi lwt,
Reference 0V all around the Tone adjust circuit, consider the effect of C3 and C8.
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Would love to be able to design a circuit all by myself. Unfortunately I don't have the knowledge for that.You start of by saying that you have to DESIGN the preamp but then you post a circuit from the internet that someone else designed. Show us the circuit that YOU have designed and explain how it works. (Or the way you think it should work. The circuit you have posted will attenuate the input signal. Not amplify it.
Les.
I would assume it does nothing if there is no voltage.Why do you think the zero volts around the tone control to be a problem ?
Les.
Did it! Am I wrong or that is a gain stage? but why is it oscillating between 3.350 and 3.295?
hi lwt,Did it! Am I wrong or that is a gain stage? but why is it oscillating between 3.350 and 3.295?
It should behave like a voltage buffer with a voltage gain of 1?Do you know how an emitter follower stage should behave ? If so give an explanation.
Les.
This is where I found the circuit: Tone Control Circuit Schematic Circuits: electronic auido circuit , Tone Control Circuit - Schematic Circuits Elektropage.comhi lwt,
I don't wish to sound blunt, but if you don't know why Q1e is swinging between these two voltages when there is an input on Vin, your chances of understanding the remainder of the circuit is in doubt.
Note the Vin 1kHz 100mV sine wave on this simulation
BTW: if I have drawn the circuit correctly and used the displayed component value, you can see the circuit does not work.
Please post a link to the original source of the circuit.
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