4 Channel Audio Processor

A project log for WiFi Centre Speaker

Essentially Version 2.0 of my other project, Network Amplifier. Retro-fitted WiFi / powered centre speaker from a 5.1 surround sound system.

ronaldronald 11/22/2015 at 11:130 Comments

One of the main components of this build is the PT2314. This not only routes the up to 4 channels of stereo input into a single stereo output, it also has built in bass / treble, volume and mute control, all over i2c. With the original network amplifier, it was the discovery of this IC within that spurred on a much more ambitious goal than was first envisioned. Well, It seems that although the functions of the PT2314 are quite powerful, there isn't much competition in this 'space', which isn't the greatest thing as although I did manage to find a ready to use module on eBay, the PT2314 has once again proved to be a little elusive to get going via i2c communication. I already knew that I would have to use a logic-level converter to compensate for the 3.3v <--> 5v differences in IO voltages between the RPi2 and the PT2314 module. The voltage conversions were working just fine, as the i2c signals that I was sending from the RPi2 were clearly seen by my oscilliscope. This however did not seem to make a difference in it's operation as the PT2314 module was from an i2c perspective - dead. I double checked everything, the VCC to the PT2314 is recommended to be 9v, so the logic levels were shifting from that voltage... Hmmm, maybe there is something here, I'm sure that the logic levels from the i2c from the original amplifier hack weren't 5v. Perhaps the VCC and the logic IO VCC aren't the same voltage, just like the RPi2. This could prevent the '0' logic signal from sinking low enough to register and is something that is worth testing. In the meantime I've ordered another couple of PT2314 modules as I can't rule out that I either damaged the device (static / etc) or that it really was just faulty. I knew that there would be a period of 'down time' between v1.0 and v2.0 amplifiers but this was just not acceptable. I made the decision to retro fit another one of the speakers from the surround sound package. A rear speaker would do nicely with a powered amp retro fit w/ Bluetooth audio (A2DP)...