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I have old Pioneer DEH-2800MPB car receiver (from 2005) and I would like to convert CD source to AUX input. I found the PML014A chip in the diagram, where the audio signal from the FM tuner and CD player is fed, and then, depending on the selected source on the panel, it is redirected to the input of the TDA7386 power amplifier.

Overall, my concept looks like this:

  1. Make a break in the CD_Lch and CD_Rch lines (by desoldering the capacitor C153 and C154).
  2. Connect the left and right channels of the AUX cable to IN2_L and IN2_R using factory 1uF SMD capacitors (C153 and C154).
  3. Connect the AUX audio signal ground to the signal ground of the S-GND power amplifier (Signal GND) in the TDA7386 power amplifier IC.

Below is a diagram of my concept: concept

Of course, I guess that it will also be necessary to insert the CD into the drive for the music to be played.

My question is - will the factory 1uF SMD capacitors be sufficient in the left and right AUX channel path, which will be connected to the IN2_L and IN2_R inputs of the PML014A source selector?

If not, what capacity of electrolytic capacitors should I use in this case and what will be their "polarity" in circuit as on the diagram above?

Maybe I am wrong with my whole idea, so I hope for some advice.

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  • \$\begingroup\$ Do you have the PML014A datasheet? If it worked with the original CD audio without problems, why would it not work with externally fed audio? What are you worried about? \$\endgroup\$
    – Justme
    Commented Mar 21, 2022 at 21:01
  • \$\begingroup\$ I'm just worried about factory 1 uF SMD capacitors and their capacity. Maybe should I use electrolytic capacitors with higher capacity (like 10-20 uF)? \$\endgroup\$
    – strusmig
    Commented Mar 21, 2022 at 21:04
  • \$\begingroup\$ @Justme I have only diagram of PML014A (datasheet is not available), here it is: ibb.co/2Sy0dDT \$\endgroup\$
    – strusmig
    Commented Mar 21, 2022 at 21:08
  • \$\begingroup\$ What particular concern do you have regarding their capacitance? The input impedance of the PML014A isn't changing. \$\endgroup\$
    – nanofarad
    Commented Mar 21, 2022 at 21:09
  • \$\begingroup\$ You already said you are worried about their capacity, but there is no explanation why are you worried about it and thinking about changing them. \$\endgroup\$
    – Justme
    Commented Mar 21, 2022 at 21:15

1 Answer 1

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Generally this should work, assuming the voltage range of your input is the same as the cd player or that the amp ic expect.

The capacitors on board should be fine. They are for dc blocking, a high pass filter basically and your source probably has its own which is also fine and expected. They are unpolarized. A higher capacity would not be needed.

Electrolytic caps are polarized and not good for this application anyway. Film capacitors would be better. But ideally you just reuse the existing ones.

Someone else did the same but added a 3.5mm jack with a switch and used the fm input (no need for a cd with blank audio) https://www-drive2-com.translate.goog/l/537152388050452583/?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en-US

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