PHILIPS MCD388 AUX IN how to ?

[tiesto23]

hi

i have PHILIPS MCD388

it have wireless subwoofer

the dvd player i lost it

i want to to add aux in input to subwoofer and use it with jack cable not wirless

any sugg how to do it

this is schematic of amp board

THNX

[Manul]

Well, you can try something like that. If you have mono signal, you need only one resistor. You may need to change the value of resistors to get desired sensitivity.

[Manul]

And if you will never use it wireless, you can remove this resistor.

[tiesto23]

Well, you can try something like that. If you have mono signal, you need only one resistor. You may need to change the value of resistors to get desired sensitivity.

hi thnx for your help

i just make as you show me

but nothing in output no sound no distoration

what is the problem ??

[Manul]

There can be two things.

1. It is on standby (off)

Make sure, that LED is not on. I marked connection to this LED.

2. It is on mute (disabled output)

If there is voltage on resistor marked with arrow, it means it is on mute. Try to remove that resistor to disable mute.

[Manul]

Sorry, I got it backwards, when LED is ON it means it is ON.

[tiesto23]

Sorry, I got it backwards, when LED is ON it means it is ON.

the led is off

i try also remove resistor

nothing happen

[Manul]

Ok, do you have voltages from power supply +24V, +12V, -12V?

[tiesto23]

Ok, do you have voltages from power supply +24V, +12V, -12V?

yes i test it now

all ok +12 -12 +24

[coromonadalix]

The TDA8947 has 2 modes of operation .... see table 5

https://www.nxp.com/docs/en/data-sheet/TDA8947J.pdf

[Manul]

Good. The problem is that STANDBY and MUTE is controlled by microprocessor and because you do not have active wireless connection, it turns off AMP.

But you should be able to force the AMP to work by removing these resistors.

[tiesto23]

Good. The problem is that STANDBY and MUTE is controlled by microprocessor and because you do not have active wireless connection, it turns off AMP.

But you should be able to force the AMP to work by removing these resistors.

thnx very much now its work

but i notice sound its a bit low

any sugg how control sound ?

i mean increase\decrease

[coromonadalix]

something like this


see the photos,    instead of the fixed 10k ohms resistors  you add this circuit

[tiesto23]

something like this


see the photos,    instead of the fixed 10k ohms resistors  you add this circuit

can you show me exactly how connect variable resistor on amp

i mean  in schematic

[Manul]

So you want volume control knob to be outside, like in this picture?

If you do not want this, then it can be done with lower resistors on AUX IN, like 4.7K, 2.2K, 1K... Lower resistors will increase sound.

[tiesto23]

So you want volume control knob to be outside, like in this picture?

If you do not want this, then it can be done with lower resistors on AUX IN, like 4.7K, 2.2K, 1K... Lower resistors will increase sound.

yes it will be good to use volume control knob

how to conect it ?

[coromonadalix]

You have to do some small work on your side,  you have to understand how potentiometers works and how to connect them.

We have laid out the works for you ...  all your answers was in the post i have made with the 3 pictures ...

You have a beautiful tutorial here:

https://www.doeeet.com/content/eee-components/passives/basic-principles-of-potentiometers-variable-resistors/

[tiesto23]

You have to do some small work on your side,  you have to understand how potentiometers works and how to connect them.

We have laid out the works for you ...  all your answers was in the post i have made with the 3 pictures ...

You have a beautiful tutorial here:

https://www.doeeet.com/content/eee-components/passives/basic-principles-of-potentiometers-variable-resistors/

thank you very much ,, i dont understand exactly how its work im a beginner thats why i ask how to setup it in schematic that way i can understand  it very well


thanx

[Manul]

Well, something like that.

[tiesto23]

Well, something like that.

thank you very much for your help & good assistance

tommorow i will add this changment and tell you the result


thnx


#staySafe