Tone Control with Loudness ?

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Hi,

I'd like to ask for some good schematic for active tone control, for treble and bass (cca+-20dB) with loudness compensation, I have saw several designs, but all of these designs uses elements that I want to avoid.

I don't like to use:

1. tone control ic's like tda1524 or lm1036
2. center tapped pot, because it is hard to find in My country.
3. "center tapped" attenuator for volume control
4. dsp :D

Exactly I am not sure is it possible to build this (loudness compensation is important) avoiding things from My list ?!

Thanks for help.
 
For the tone controll you could use an active Tone controll that Boosts and also cuts....You can use a couple of opamps to do this....

Maybe something like this:


practicemaneq.gif



Cheers
 
thoronx said:
Hi,

I'd like to ask for some good schematic for active tone control, for treble and bass (cca+-20dB) with loudness compensation, I have saw several designs, but all of these designs uses elements that I want to avoid.

I don't like to use:

1. tone control ic's like tda1524 or lm1036
2. center tapped pot, because it is hard to find in My country.
3. "center tapped" attenuator for volume control
4. dsp :D

Exactly I am not sure is it possible to build this (loudness compensation is important) avoiding things from My list ?!

Thanks for help.

Loudness compensation is simply lifting the bass and treble at lower listening levels. This is to compensate for the hearings losses at low sound levels.
 
From My point of view Loudness Compensation (with Tone Control) is a 'must' for an amp, specially when I listen music at low volumes as I do frequently ...

I had extreme amount of Google (web and image) queries in the past few months about Loudness compensation or practical implementation of Fletcher–Munson curves,

maching my requirements (no tone control ic, no center tapped pot, no tapped attenuator, no dsp), but without any significant result (schematic+pcb), what was found is a few interesting schematic:

1. PC Preamp Project By Dave Erickson http://www.djerickson.com/pcpreamp/, the schematic is http://www.djerickson.com/pcpreamp/pdf/Pc_preamp.pdf

2. ON Semiconductor's document "Audio Circuits Using the NE5532/4" http://www.eetasia.com/ARTICLES/2007FEB/PDF/EEOL_2007FEB26_ACC_AN_01.pdf


...then I gave up google.


Next I had an idea to find some service manuals for any legacy amplifiers that uses Loudness button (amps mainly produced in the 70's 80's 90's ...) so I went to

http://www.eserviceinfo.com/ and with help of Google (to find model of the amp) downloaded different service manuals, and now I am analysing them ... Sony's implementation in amp model TA-FE210 is looking good ...
 
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Thronx, I built many pre-amps based on the Baxandall bass/treble boost and cut circuit and back in the early 80's it was relatively easy to get log pots with a CT to do loudness control. Looking at the above circuits, I'd say the Dave Erickson circuit looks quite good - classic Baxandall but with the added loudness control for low levels. As in all things, make sure you don't overdo the loudness - you really don't want this having any effect (or minimal effect) once you get to normal listening levels (but of course, you can alway turn the loudness off if you want). You can also downwload LTSPICE and experiment with the values to fine tune your final effort.
 
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