I need a volume controller for my Altec Lansing ATP 5 speakers

Normally these low end system components depend on each other and cannot be interchanged with components from other system. So if one of the components (subwoofer or right control satellite speaker) breaks or gets lost the whole system is unusable...
I was in the same situation. Got a subwoofer from VS4121 without original satellite speakers. I acquired satellite speakers from Altec Lansing 251 which used same connectors but the internal wiring was different and incompatible. Speakers are also glued together so it is impossible to open without damaging it. Obviously there is no service documentation anywhere..
But if you like electronics you can try to make something based on the information below:

Altec Lansing VS4121 connector pinout:
Take the male connector (from right satellite speaker) and number pins in first row from left to right as 1-3, pins in the second row as 4-7, pins in the bottom row as 8-9 and the circle enclosure as 0. Then:
0 - Ground
1 - Speaker Right
2 - Treble (seems just like voltage control but may need to be confirmed: Min=0V; Max=voltage from Volume control Pin 9)
3 - Head Set Right
4 - Bass signal (not sure what the exact original design is as I have not opened the speaker) But seems like they use 50K potentiometer and some sort of RC low pass filter configuration. When potentiometer is set to Min it is shorted with ground. When set to Max it is taking signal from Right and Left Head Set (pins 3 and 5) combined through some larger resistors and low pass filter.
5 - Headset Left
6 - Ground for Headset (grounds 0 and 6 seems to be connected in the subwofer but within the right satellite speaker they seem to be isolated with separate leads to sub)
7 - Power ON/OFF. When OFF or headset jack plugged then 0V. When ON and headset jack unplugged then 5V
8 - 5V Power in
9 - Volume (min=0V; max=5V). It seems they use 50K potentiometer but probably anything >10k should work.

At minimum for standalone subwoofer you will need to implement:
- Power On/Off (switch between pins 8,7)
- Volume control 50k potentiometer (probably anything between 10k and 50k will do) between pin 7 and 0 with variable output to pin 9
- Bass control - join two resistors R (I used 7k) and call this join point A. Attach other ends of the resistors to pins 3 and 5 respectively. Attach 50k potentiometer (I used 10k) between point A and ground 0. Attach Variable pin of the potentiometer to pin 4 (Bass input signal). Attach capacitor C between Pin 4 and Ground pin 0 (I used Electrolytic 1uF with negative end to ground) . Resistor R and capacitor C should make simple passive low pass filter (Google for formula) that should short any frequency higher than 80-120Hz to ground and feed frequencies lower than 80-120Hz to pin 4.

PS: I managed to hack 251 control satellite speaker to somewhat work with VS4121 Subwoofer but that is another subject. All electronic parts were salvaged from old broken TV so total cost was $0 but took several days of tinkering for speakers that I could buy used for $10-20 :)

can anyone help me with the Altec Lansing VS4121 2.1 Channel i need the wiring diagram of 9 pin cable i broke it. please mail me the layout at [email protected]

did you try ebay jim

Hi there, by saying you found, do you mean that is a complete set, I have the same speaker set, and the volume control knob is on one of the satellite speaker. If you are missing that speaker I doubt that you can do anything with it because you will most likely find them for sale as a set and not separate. Thanks hope this helps.

Speaker is bad or the cable may have come loose. Has it been knocked around? If so it may have pulled the cable loose inside the speaker, try playing a song and wiggle the wire and push the wire in gently to see if it starts to play if it does you have found your problem. If not then the speaker is bad and I don't remember if you can pull it apart and buy a new speaker to install in it. Thanks for using Fix-ya and if this helps please rate this free question.
Avid101

check the port to which u have connected ur speakers. And also install proper driver

Dell (Altec Lansing) A425 Subwoofer Pinouts

This is a standard female DB-9 serial port.
Here are the pinouts.

Pin 1 = Left Speaker Out +

Pin 2 = Left Speaker Out - (Common Ground)

Pin 3 = Left Line In +

Pin 4 = Right Line In +

Pin 5 = Left/Right line In - (Common Ground)

Pin 6 = Right Speaker Out +

Pin 7 = Right Speaker Out - (Common Ground)

Pin 8 = Power A

Pin 9 = Power B

Jumper (short) Power A to B to turn on.
If you want a volume control you need to put one on the inputs. You will buy buy a stereo volume control or potentiometer.
Here is some info on how to do this.
http://g4tv.com/screensavers/features/43665/Pump-Up-The-Volume.html

Cheers!

there is a lose connection near the main speaker .When i move it sound stops 

I am also experiencing the same problem as yours...

Hi Saburine
http://www.teksale.com/computers/computerparts/listings/ALTEC%20LANSING%20ATP3%2027W%20RMS%20BLACK%203PC%20SPEAKERS.htm
here you can get the complete drivers.