Adding Input to the Amplifier circuit!

[fazidurrani]

Hi All,

I am new to Electronics and have some basic understanding. I've a subwoofer with builtin amplifier which has 8 pin din connector to connect to right satellite speaker. Right satellite speaker has RCA input jacks, volume control and power button. Circuit in Right side speaker takes RCA and feed the input to subwoofer amplifier on pin 5 and 6. pin no 7 feeds the amplified output to right speaker.
I've lost satellite speakers and now want to install RCA pins in the subwoofer box. So, i can use subwoofer with any aftermarket speakers. I've technical guide available but need guidance on how to do it?

I don't necessarily need volume functionality. i just want to install female RCA pins in the subwoofer and want to know if i can splice connections directly to pin 5 and 6 or do i need to add additional components. how i will feed the power to the subwoofer main IC?

Here is the link to the manual of circuit design (Both subwoofer and satellite speakers.)

https://www.dropbox.com/s/j7tt82c7sfy2yje/YST-MS50.pdf?dl=0

Alternatively, can i install this in the car? how i can setup the power source from car battery? any help would be much appreciated. thank you

 

[Audioguru]

How will you get +27.4V and -27.4V (54.8VDC total) from a 12V car battery?
Pin 5 of the 8-pins connector is the +12V output of a 12V regulator that is fed +27.4V in the normal system and the regulator will blow up if you feed +12V from a car battery to its output.
There is also a -12V regulator that will not work from a car battery.

 

[fazidurrani]

Hi,

Thanks for the reply. I didn't look into calculation of voltage, i just noticed that pin 1 and 2 has +12 and -12v respectively which is going to the right speaker. can you please guide me how i can setup the input in subwoofer to work on electrical socket at home.

 

[Audioguru]

The 6.5" speaker is too small to be a sub-woofer. It will be an ordinary woofer.
You are correct, the inputs to the woofer amplifier are pins 5 and 6 with the ground and RCA shields on pin 3.

 

[fazidurrani]

Thanks for replying. yes, this system has total of 80watt power out of which 40watt is subwoofer output.

So, what i did is to cut the 8 pin din connector from 1 side. i've 8 cables now, i've already traced them. there is a mesh around the cable which i believe i can use as ground.

Pin 5 SRI +ve (i assume its right input)
Pin 6 SLI +ve (i assume its left input)
Pin 7 is the Right speaker +ve output.
Pin 1 is +12v
Pin 2 is -12v
Pin 3, Pin 8 and Right speaker negative are all ground.
Pin 4 is power input for power Amp IC.

So, should i just splice pin 5 to +ve of right RCA and -ve to ground mesh, pin 6 to +ve of left RCA & -ve to the mesh. will that input work?
what about connecting power, can i connect pin 1 to the pin 4? since pin1 has output +12v and pin 4 seems power input to POWER AMP IC, will that work? do i require to use pin 2 (-12V) anywhere?

 

[davenn]

do i require to use pin 2 (-12V) anywhere?

going by the schematic, -12V is used through out the amplifier system

 

[fazidurrani]

So, will that pin configurations work which i mentioned in the previous post?

 

[Audioguru]

I cannot find a datasheet for the obsolete Sanyo power amp IC. It looks like pin 4 of the connector applies +12V to turn on the IC slowly to avoid a loud POP! If you connect the pin 4 to pin 1 then the amplifier will be on all the time.

Do not connect pin 2 to anything.
The left and right satellite speakers can be connected as you posted.