Hello all,
I would like to build an amp (based on the TPA3220), which could switch between Mono and Stereo automatically when a second speaker is connected.
I know you can accomplish this on devices with Jack outputs (a L/Mono channel and a R channel) , thanks to switched jacks on the R socket which will allow switching to stereo when a jack is plugged in.
Basically, I would like to do the exact same thing but instead of connecting jacks, I would like my amp to output mono when only one speaker is connected, and Stereo when you connect the + and - copper cables of a right speaker.
Do you know if this is possible ? Do I need a particular type of connector, or do you have any ideas to accomplish this that I might not have thought of ?
Thanks a lot in advance !
I would like to build an amp (based on the TPA3220), which could switch between Mono and Stereo automatically when a second speaker is connected.
I know you can accomplish this on devices with Jack outputs (a L/Mono channel and a R channel) , thanks to switched jacks on the R socket which will allow switching to stereo when a jack is plugged in.
Basically, I would like to do the exact same thing but instead of connecting jacks, I would like my amp to output mono when only one speaker is connected, and Stereo when you connect the + and - copper cables of a right speaker.
Do you know if this is possible ? Do I need a particular type of connector, or do you have any ideas to accomplish this that I might not have thought of ?
Thanks a lot in advance !
Your dealing with an audio power IC that is controlled by the logic built into it.
This includes the output DC control and subset startup control , in other words the chip looks for certain conditions to be achieved in a logical manner so that correct operation can take place .
What you want is logic controlled programming without any mechanical means but totally through the chip logic .
That requires Firmware programming and the expertise to do that .
Reprogramming is possible if you have the associated knowledge to change digital logic firmware , while I can do much to my Linux computer I do not have the full expertise of a top system programmer in computer language but there must be somebody on DIY Audio who programs at that level ?
In simple language ---you will need more than a "connector ".
This includes the output DC control and subset startup control , in other words the chip looks for certain conditions to be achieved in a logical manner so that correct operation can take place .
What you want is logic controlled programming without any mechanical means but totally through the chip logic .
That requires Firmware programming and the expertise to do that .
Reprogramming is possible if you have the associated knowledge to change digital logic firmware , while I can do much to my Linux computer I do not have the full expertise of a top system programmer in computer language but there must be somebody on DIY Audio who programs at that level ?
In simple language ---you will need more than a "connector ".
Thanks a lot for your answer !
I didn't expect I would have to go all the way to firmware reprogramming for this task, indeed ...
It surprises me that it's such a difficult task because it seems on paper it would be a pretty common option people would want, to switch easily between one or two speakers.
I'll try to find another solution, maybe working with the DAC directly to send the mono signal.
Thanks your your answer anyway, if someone else thinks of a way to do it, please don't hesitate 😉
I didn't expect I would have to go all the way to firmware reprogramming for this task, indeed ...
It surprises me that it's such a difficult task because it seems on paper it would be a pretty common option people would want, to switch easily between one or two speakers.
I'll try to find another solution, maybe working with the DAC directly to send the mono signal.
Thanks your your answer anyway, if someone else thinks of a way to do it, please don't hesitate 😉
You could use a LEM current sensor on the output wire inside the amplifier behind the speaker terminal,
to sense the presence of current to the speaker. With no load, there would be no current to sense.
The LEM sensor is designed to have no measurable effect on the current signal that is measured.
Detect the audio by rectifying and filtering the LEM output to DC, and convert it to a logic control signal.
You would want a time delay between a sudden lack of current sensing and switching back to mono,
to prevent unwanted mode switching. An example (there are also cheaper current sensors):
https://www.lem.com/sites/default/files/products_datasheets/hx_03_50-p_ver15.pdf
to sense the presence of current to the speaker. With no load, there would be no current to sense.
The LEM sensor is designed to have no measurable effect on the current signal that is measured.
Detect the audio by rectifying and filtering the LEM output to DC, and convert it to a logic control signal.
You would want a time delay between a sudden lack of current sensing and switching back to mono,
to prevent unwanted mode switching. An example (there are also cheaper current sensors):
https://www.lem.com/sites/default/files/products_datasheets/hx_03_50-p_ver15.pdf
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Thanks a lot for your feedbacks, I really appreciate it.
About the Jack connector, this is what I found the inspiration from, but I can't use a jack in my configuration, hence this question 😉
This seems like a great solution. I'll definitely dig into this. As you said, the complexity would come from converting it to a useful logic signal and take care of the delay to avoid switching between mono and stereo too frequenty, but this definitely seems achievable. Thanks!
About the Jack connector, this is what I found the inspiration from, but I can't use a jack in my configuration, hence this question 😉
This seems like a great solution. I'll definitely dig into this. As you said, the complexity would come from converting it to a useful logic signal and take care of the delay to avoid switching between mono and stereo too frequenty, but this definitely seems achievable. Thanks!
After rectifying and filtering the signal, use a comparator (with substantial hysteresis)
to derive a logic level signal. Then use this signal along with a delay timer output logic level
(with say 30s delay) for suppression of unwanted rapid switching back to mono
during pauses in the music.
to derive a logic level signal. Then use this signal along with a delay timer output logic level
(with say 30s delay) for suppression of unwanted rapid switching back to mono
during pauses in the music.
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