digital audio switch

Thread Starter

zhim57

Joined Nov 26, 2022
6
Hi I do not know anything about circuits , but am in a need of a switch with multiple audio inputs , would like it to be automatic and also if possible to have manual control , where 8 or more (ideally up to 32 audio inputs) to be selected to go through the output , one by one in a loop for a preselected time each. also to be able to select and stay on one of the inputs at a time and the input ID to be shown on a display. any help is highly appreciated.
 

shell.albert

Joined Jul 23, 2014
14
As you mentioned, your audio signal is digital. Normally, digital audio signals are not very fast.
I know the fastest speed is 192Kbps.

You can choose A simple 74 series IC to multiplex named 32 -1 decoder . Just like a 8-3 decoder.
Also there're available professional audio signal input multiple channel multiplexer in the market.
 

Thread Starter

zhim57

Joined Nov 26, 2022
6
thank you , my wording was not correct , the switch I meant is to be digital (opposed to a mechanical mixer with buttons that I am waiting to be delivered) , the audio inputs are from very cheap microphones and probably will be analog .
Thank you for the multichannel multiplexer switch idea, It is great , but I do not have the skill to design the board around it .
 

Irving

Joined Jan 30, 2016
3,190
Welcome to AAC!

Switching the microphone signal is a bad idea. Microphone outputs are very low level, a few mV at best and switching at that level will introduce noise into the system that you wont be able to remove further along. Ideally each mic should have a pre-amplifier to boost the signal before the switch.
 

Thread Starter

zhim57

Joined Nov 26, 2022
6
Thank you Irving, that makes a lot of sense , do you think it is a good idea to have all pre-amplifiers on the same board or should I connect individual ones shortly after each microphone and then run the wires to the switch?
 

Irving

Joined Jan 30, 2016
3,190
Thank you Irving, that makes a lot of sense , do you think it is a good idea to have all pre-amplifiers on the same board or should I connect individual ones shortly after each microphone and then run the wires to the switch?
No reason not to, as long as some basic precautions are taken to avoid crosstalk between channels, eg power supply decoupling, clean ground planes, etc. But ideally pre-amp shuld be close to mic.
 

AnalogKid

Joined Aug 1, 2013
10,176
Money equals quality. In this case, more expensive chips have lower distortion, lower noise, and wider bandwidth. An LM324 might work as a preamp for four mic channels, but a quad opamp from Burr-Brown (now a part of TI) will have much better performance.

The same goes for the analog switches. Low cost CMOS CD405x or CD4067 can be cascaded to form a 32:1 mux, but much better mux devices are available from Linear Technology, Analog Devices, etc.

Please give more details about your signals (peak amplitude, max bandwidth, etc.) and the intended use for the output.

Separate from that, automatic stepping through the inputs is relatively simple. Direct addressing is more difficult. Combining the two certainly can be done, but without a microcontroller it will take a lot of chips.

ak
 

Thread Starter

zhim57

Joined Nov 26, 2022
6
Money equals quality. In this case, more expensive chips have lower distortion, lower noise, and wider bandwidth. An LM324 might work as a preamp for four mic channels, but a quad opamp from Burr-Brown (now a part of TI) will have much better performance.

The same goes for the analog switches. Low cost CMOS CD405x or CD4067 can be cascaded to form a 32:1 mux, but much better mux devices are available from Linear Technology, Analog Devices, etc.

Please give more details about your signals (peak amplitude, max bandwidth, etc.) and the intended use for the output.

Separate from that, automatic stepping through the inputs is relatively simple. Direct addressing is more difficult. Combining the two certainly can be done, but without a microcontroller it will take a lot of chips.

ak
hi , thank you, I found IC for both pre-amplifier and for a 32 to 1 switch at mouser electronics, but these are just the IC , I do not know how build the actual devices, regarding the peak amplitude , no idea also, no idea what max bandwidth can be achieved

the direct addressing is important as the end user will need to be able to select the desired input .

My goal is a device of two parts where the end user will have the where the switch would allow the user to listen to different audio feeds on a wireless receiver, will be able to control the switch remotely and also will have indication on the end receiver which channel is playing and will be able to change the channels from the end receiver.

The cost is important but the quality and features are more important .
 
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