I saw an article on CNET a while ago that showed an amplifier that was only $20 that had a simple volume, bass and treble controls and an on/off switch. This would be perfect for me but I want surround sound for my computer, right now I have two full size receivers hooked up. I would only use one but the surround inputs on both of them are only hdmi and optical. My sound card (Xonar DG) only has surround for regular 3 3.5mm connections. (the optical cable is only 2.1) So I was wondering if there was any really cheap (around $50) receivers or amplifiers that have the following abilities:
1. Have at least 4 channel surround sound
2. have the regular 3.5mm jack input (1 for front, 1 for surround, 1 for center/sub)
3. (Not necessary) Headphone port with decent headphone quality (headphone amp)
More about :cheap channel surround sound amplifier
The output of your sound card is 3.5 mm. You need 3.5mm to RCA male adapters, to plug into the existing amplifiers. The amplifiers don't decode the surround, the computer is decoding it.
There is no advantage to using one amp, you already have what you need. Unless you really "want" one amp.
In that case ONE amp, with 4 RCA inputs, you just need the adapters.
You will have a hard time finding an amp with 3.5 mm inputs. Almost always, you will need to use adapter / patch cables, 3.5 mm stereo to left / right RCA male plugs.
There is no advantage to having the amp decode the signal, and a cheap amp is a downgrade. The computer decodes the surround and the analog out goes directly to an amplifier.