ADG408 and 409 multiplexer

Hello, i want to replace the multiplexers in audio devices with these types. The old ones are CD4051 and 4052 CMOS. Yes, i know they are not pin compatible, but this won´t be a problem. The ADG type should have some advantages as low noise and the cut-off before switching. 

Now, i want to know if i have to change the design for the following buffer stage or could it be used like for the CD types? I have not found any sample circuits or plans for audio usage...

I would be glad if anyone has some tips or informations for me

Thanks 

Tom

  • 0
    •  Analog Employees 
    on Feb 23, 2021 11:58 AM 1 month ago

    Hi, Tom.

    Could you share more details about this application? Information like voltage range, supply voltage, operating frequency and a schematic will help us better understand your question.

    Yours sincerely,

    Igor.

  • Hi Igor,

    the application is a vintage amplifier from DUAL. They have built two really heavy amps called RC440 and RC441. After this they haven´t designed anymore amps. Meanwhile only the name exists. They use the CD4051 for switching the audio inputs, the standard volume poti has been changed to two 4051 for dB multiswitching, as balance, bass and treble too.

    This chips operate with +/-7.5V regulated; the op-amps as buffers with +/-15V. The unregulated supply is +/-18V here. Frequency is from 20HZ to 20KHZ up; the usual audio range.

    I have added a snip of the input multiplexer.

    Regards,

    Tom

  • System has thrown out my picture... once again.

    I´m working on a vintage amplifier made by dual (company originally doesn´t exist anymore). They have bought out in their last steps two amps with a complete multiplexer control (no potis inside). All inputs, volume control, bass treble and balance is switched by CD4051 multiplexers. For this age a revolution. They are working with +/-7.5V regulated; the buffer op-amps +/-15V and the max of this power source has +/-18V. The frequency is the normal audio range; at least 20-20000HZ with no deviation.

    Now. i want to replace this chips with the named types cause the they have no break before... and are not really low noise.

    I try to find a solution to upload the schematics, but in www you can find easily the plan of the DUAL RC440 amp.

    Regards

    Tom

  • +1
    •  Analog Employees 
    on Feb 25, 2021 4:44 PM 1 month ago in reply to Tom1966

    Hi, Tom.

    Apologies for the late reply.

    If the voltage passing through the switch are withing the switch's rails, VDD and VSS (+/-7.5 V in your case), it should be okay for you to replace the CD4051 and CD4052 with the ADG408 and ADG409.

    Your frequency range should be within the -3dB bandwidth of these two switches as well.

    If you are looking at higher precision and low signal distortion, I recommend that you use the ADG1408 and ADG1409.

    Unfortunately, I did not find the schematics for the DUAL RC440/RC441 amp you suggested. Could you share these with me?

    Yours sincerely,

    Igor.