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TMUX4053: Pop-free switching of Audio Signals

Aditya Nandwana
Prodigy 40 points
Part Number: TMUX4053
Other Parts Discussed in Thread: TS5A22364, TMUX4827, TMUX6236

Hello, 

I'm trying to use TMUX4053 to replace relays in a commercial application. The circuits are high--gain audio preamps and guitar distortion circuits, with large signal swings. 

When using this chip to switch between audio signals, there is a significant pop that can be extremely loud through an amplifier or speakers/PA system. 

I've used series resistors, DC blocking caps (2.2uF) and 1MΩ resistors each switch input and output, as suggested by the circuit in the following link, but find it impossible to reduce this pop to an ignorable level. www.geofex.com/.../cd4053.htm

Is there any way to get pop-free/click free switching from analog switches like TMUX4053? I've had success with switching DC, but not audio.

Thank you!

  • 0
    TI__Genius 17610 points

    Hello!

    So I would like for you to check out this faq that talks click/pop noise reduction for audio applications using multiplexers.

    Basically  while  the circuit recommendation helps your design it doesn't take into consideration another possible cause of pop in your system. We should consider   the fact that there  is internal parasitic capacitance in your multiplexer that is causing a click/ pop noise when it is quickly discharged by being  disconnected and reconnected to your speaker system.

    I would suggest looking into the TS5A22364 as it has internal circuitry to limit the click/ pop.

    What are the voltage levels of your system? Depending on that question the device i suggested could work for you.

    Please let me know what you think and I will be happy to help!

    regards,

    kameron

  • 0 in reply to Kameron Hill
    TI__Genius 17610 points

    Hello 

    Any update on this?

  • 0 in reply to Kameron Hill
    Prodigy 40 points

    Hi Kameron, 

    sorry for the late reply - I should have been a bit more clear in my original post. The TMUX4053 is not handling power amplification connections to the speaker, but is replacing the function of the traditional DPDT/3PDT bypass switch in a guitar effect. This is illustrated very well here: http://www.muzique.com/lab/truebypass.htm

    Despite our best efforts, we haven't yet been able to eliminate pop from the TMUX4053  "true" bypass method. I think a big factor here is the fact that there is a significant change in the volume when going from unbuffered, high-impedance guitar levels, which are around 100mV, to almost 20Vpp at the guitar pedal output. Apart from overcomplicating things with additional mute circuitry, there don't seem to be any options. 

    We'll keep experimenting, but are less optimistic about the outcomes at this point. For now, we will stick to using a DPDT relay. 

    For what it's worth, JFETs seem to be a good choice as the slope of switching can be regulated unlike CMOS switches. 

    If you have any other ideas, do let me know! Thank you! 

  • 0 in reply to Aditya Nandwana
    TI__Genius 17610 points

    Hello Aditya,

    Thanks for the extra info!

    So I think one more thing you can do is try the  the TMUX6236 or TMUX4827 as they can handle your signal voltage range and have a feature called  a break before make that helps in audio applications.

    In addition please take a look at this app note that talks about replacing relays with multiplexers

    Please update this thread if you have any further questions after experimenting .

    Regards,

    Kameron