This might be the simplest active tone control circuit, but is there a way to modify the gain and frequency response?
The circuit as given gives a gain of +/-20 dB which I think is huge and distorts given today's digital sources with 1vpp output.. Is there a simple way to modify the gain to +/-10 dB?
1. What is the effect of reducing the variable pots 100k to 47k?
2. What is the effect of replacing the Emitter resistor 1k and connecting to ground?
The circuit as given gives a gain of +/-20 dB which I think is huge and distorts given today's digital sources with 1vpp output.. Is there a simple way to modify the gain to +/-10 dB?
1. What is the effect of reducing the variable pots 100k to 47k?
2. What is the effect of replacing the Emitter resistor 1k and connecting to ground?
Attachments
Here is some design info, use figure 12, which is a better circuit: https://sound-au.com/dwopa2.htm
Reducing the pot resistances would raise the frequencies where the tone action starts.
The range of bass adjustment would also be reduced a little.
You don't want to short out the emitter resistor, since the circuit would not work.
And the 1k is bypassed at signal frequencies anyway.
Reducing the pot resistances would raise the frequencies where the tone action starts.
The range of bass adjustment would also be reduced a little.
You don't want to short out the emitter resistor, since the circuit would not work.
And the 1k is bypassed at signal frequencies anyway.
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Yes, look at figure 12 in the link.
The series resistors with each pot determine the amount of gain/cut.
Increase them all proportionately, until the gain/loss is what you want.
Don't change the pot values.
To change the frequencies as you describe, change the capacitors. Bigger for bass, smaller for treble.
The series resistors with each pot determine the amount of gain/cut.
Increase them all proportionately, until the gain/loss is what you want.
Don't change the pot values.
To change the frequencies as you describe, change the capacitors. Bigger for bass, smaller for treble.
Rod‘s equations are incorrect. He notices himself that he gets wrong values. Use the equations in Baxandall’s original paper.
There are really four variants. On the bass side you can have one capacitor shunting the entire pot, or two meeting at the wiper. On the treble side you can have two capacitors, one leading to each side of the pot, or one capacitor in series with the wiper.
At this point I am going to refer you to the National Semiconductor Audio Handbook, 1976, pp 2-44 to 2-48, which you will find online, or the Tone Controls chapter in Douglas Self, Small Signal Audio Design, for a full discussion of the differences. They aren't great but they affect the calculations. The choice may simply come down to cost.
Well not really. The equations show you what you can change and what it will affect. SPICE knows that, but it can’t tell you. For example, changing any of the four RIAA components will move the zero of the transfer function. That’s obvious from the transfer function itself, but only several SPICE experiments will show that, and it would be easy to miss.
here some advices:
https://learnabout-electronics.org/...line in Fig.-,4.2.,true bass and treble boost.
https://audiohertz.com/2020/09/09/what-the-fck-is-a-baxandall-eq/
https://www.duncanamps.com/tsc/index.html
the original article you will find in the attachment.
Luxman's integrated amp models L510 and L540 (so as several vintage Pioneer receivers) use an extended equalizer version with additional cut-off switches - check out last page of the attached service manual.
check out also this threads
https://www.diyaudio.com/community/threads/modified-baxandall-tone-control.398364/
https://www.diyaudio.com/community/threads/active-baxandall-tone-amp-design-ideas.394177/
https://www.diyaudio.com/community/threads/asymmetric-baxandall-tone-control-circuit.401494/
https://www.diyaudio.com/community/...entiometers-in-baxandall-tone-control.361027/
https://www.diyaudio.com/community/threads/baxandall-eq.40902/
https://www.diyaudio.com/community/threads/baxandall-differences.289173/
https://learnabout-electronics.org/...line in Fig.-,4.2.,true bass and treble boost.
https://audiohertz.com/2020/09/09/what-the-fck-is-a-baxandall-eq/
https://www.duncanamps.com/tsc/index.html
the original article you will find in the attachment.
Luxman's integrated amp models L510 and L540 (so as several vintage Pioneer receivers) use an extended equalizer version with additional cut-off switches - check out last page of the attached service manual.
check out also this threads
https://www.diyaudio.com/community/threads/modified-baxandall-tone-control.398364/
https://www.diyaudio.com/community/threads/active-baxandall-tone-amp-design-ideas.394177/
https://www.diyaudio.com/community/threads/asymmetric-baxandall-tone-control-circuit.401494/
https://www.diyaudio.com/community/...entiometers-in-baxandall-tone-control.361027/
https://www.diyaudio.com/community/threads/baxandall-eq.40902/
https://www.diyaudio.com/community/threads/baxandall-differences.289173/
My main complaint with 99% of tone controls is the bass accentuation that was normally designed in above 100Hz. A few extra components plus a switch could have made it frequency selectable.
Feel free to check out Doug Self’s preamp from Linear Audio (volume 5) to get some ideas for a really interesting tone control. It’s frequency selectable using a potentiometer. At full boost the tone stack doesn’t clip until about 4.7V peak input.
https://linearaudio.net/douglas-self-preamp-linear-audio-vol-5
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