Surround Sound From 3.5 Mm Stereo





Introduction: Surround Sound From 3.5 Mm Stereo

About: Electronics expert

This Instructable describes how I built a surround sound system for use with a 3.5 mm stereo output. The goal is to extend surround sound experience from any 3.5 mm stereo headphone output with quality and simplicity. Works great with PCs, MP3 players, CD players, tape recorders etc. This is a low power (around 1 Watt) version of the ABC surround sound decoder.

You will need the following items to build 3.5 mm surround sound:
- Parts shown on attached schematic.
- Plugboard.
- 4 heatsinks (1.5" x 2" copper or aluminum sheet metal).
- 4 speakers (4 - 8 Ohm, about 3 Watt nominal power). Almost any type of speaker works:
Computer speakers, satellite speakers, small speakers, big speakers, etc.
- Wire.
- 4 phillips 6-32X1/4 nylon machine screws.
- 4 nylon 6-32 hex nuts.
- Heatsink grease.
- 12V, 500mA or more power supply.
- 3.5 mm plug to 3.5 mm plug cable.

Drill, solder gun and soldering accessories, cutters, tweezers, wirestripper.

Step 1: Making the Circuit

The circuit I used consists of a power amplifier with 3.5 mm jack input and the surround sound decoder. 3.5 mm input jack can be replaced by cable with 3.5 mm plug if desired.

Mark future hole center by placing T3 transistor at lower left corner of the heatsink. Drill hole in each heatsink.

Assemble circuit shown on schematic. This step requires some assembling and testing skills.

Apply a small amount of heatsink grease on T3, T4, T7, T8 transistors and secure heatsink on each of them using screw and nut. Warning: heatsinks should not touch each other!

Step 2: Speaker Preparation

I used pair of low power Phillips speakers available at Walgreens and pair of old PC speakers.

Attach wires to each speaker paying attention on polarity.

Step 3: Final Connection

Any 12V, 500mA power supply is sutable for this application.

Connect power supply and speakers to circuitry - system is ready.



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    20 Discussions

    To anyone reading this instructable for the first time,this is a HAFLER setup,dressed up as an elaborate "decoder".The same results can be achieved (for free) by connecting one or two speakers across the + terminals of your amp as described all over the internet.

    An active version with centre and sub outs can be found here-

    And as part of a complete system here -

    You can add a center channel simply by running a wire from the + terminal of the 2 stereo speakers to the terminals of the center channel speaker. It results in only a slight reduction of volume, but true center channel output.

    This is not really surround sound. Surround sound is 4 distinctive and different channels. This is surround stereo. Stereo sound that is duplicated to front and side channels

    Can u provide detailed component list used in making the amplifier and decoder. you have used to one more socket, for connecting speakers. can u tell in detail how u connected the other speaker with out socket(soldered wire). because i too have same type speakers one set with jack and another without jack.

    This looks like it a slightly more complicated version of the Hafler circuit: The Hafler system can easily be added to a two speaker system with its own amp using a pair of old speakers. leaving out the front centre speaker. I'd be interested in comparing the two eventually. You can see it here in another post too: Keep on truckin'!

    Feed left and right channels into ABC decoder to get four outs, leave subwoofer as is.

    Why do people leave the product stickers on laptops and lcd displays? I know I'm a little off topic but it bugs me :p Anyway, great 'ible.

    1 reply

    This laptop belongs to lab, no one cares about lables as long as it does the job.

    Center speaker is not part of this concept. Sudwoofer can be pulled out from any front speaker via crossover network.

    ok sounds good thanks.. ill probably be doing this i my basement now

    What's the output wattage of the speaker? Can you use the ABC decorder part for a regular stereo amplifier?

    4 replies

    0.5 W and up will work well with this option, wattage is limited by amplifier's output power and ABC decoder power dissipation. I'm using ABC decoder with regular stereo amplifier for many years and recently with stereo output of Plasma TV.

    Thanks, but what is the approx. output of the stereo amplifier per channel?

    I'm working on USB Surround Sound - ideal for computers.