Some TI TPA-3116 Questions

[MrCray]

Hi everyone,

I am doing some car audio stuff and was looking at the wonderful $17 boards on aliexpress. I had a couple of questions that don't seem to have been answered here yet, and you guys seem like the right ones to ask.

Does anyone have one of the 2.1 boards, and could they please tell me the number on the small chip that is on the sub input(or a pic), I'm thinking of fooling with it some. From the pic I've seen I can't figure out if it's an op-amp filter or a dedicated filter.

And, those generic "150W" DC-DC converters, what are the actives in them? I'm thinking of bridging 2 or more together, if anyone has done this I'd really appreciate any insights they might like to share

Thank you in advance, I've been lurking here for a while now and figured I should say hi.

 

[John8]

Hi,
I have a 2.1 board from ebay which I assume is the one you are referring to.
The small IC is a TL074 quad op-amp. One op-amp is used to sum the L and R inputs feeding the active LPF for the sub. amp. The remaining 2 are used as a phase splitter to drive the sub. amps balanced inputs.

 

[MrCray]

oh cool Thank you, has anyone tried replacing the tl074 for something like an opa4134? I'm using a peerless sub ("Vifa" brand) and wondering if there will be a noticeable difference.

 

[John8]

The TL074 is a good op-amp for low distortion audio applications when not driving low impedance loads or being used in high gain applications. In this amplifier I doubt if any benefit will be had by changing the amp to a more expensive one. Why take the risk of damaging the board if you are not skilled in the re-working of surface mount components.
There is probably more mileage in tuning the output filters to suit the impedance characteristics of your speakers and improving the supply decoupling if you are after the ultimate in performance. The amplifier section basically follows the TI application note and much has been written about modding these and similar amplifiers.
In my humble opinion, not being blessed with golden ears, they are a fantastic little amplifier. Just listen and appreciate the performance of an inexpensive, good quality, class D amplifier.