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TPA3116 2.1 Amp - Step by Step Modifications

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  • #16
    Originally posted by Millstonemike View Post
    A quick reply for now ...

    I'll take any bet that the sub frequency adjustment pot is really sub volume pot. The basic design of that board has a fixed LP circa 107 Hz (if the parts were populated correctly). The three pots are: Sub volume, L-R volume and overall volume. The sub/L-R vol pots can be used to tailor the sub volume vis-a-vis the L-R volume.

    Also, I'd advise to read up on Li-Ion cells (18560) batteries. You cannot just charge them with an AC adapter. They need need charge current management and cell protection (over/under voltage, max current, etc.) lest they catch fire. Remember those news reports of the hover boards catching fire. I have a 6S Li-Ion battery pack with a computer charger that manages each cell during charging. And since this is a stationary system, why not just use a 24 V DC, 5 A "Brick" AC PS?




    Hey, thanks for the info, I feel like you're probably right and there is either incorrect or misleading information in the item description, I'll find out when I get it.

    On the 18650 Li-Ion batteries, I did not mean to say I would be using some diy charger, I have two "official" 4 bank chargers used by the vaping community for 18650 batteries with all the safety features you mentioned., like this:

    http://lygte-info.dk/review/Review%2...l-44%20UK.html

    I haven't had a fire or explosion in 4-5 years of using these, my other one is a Nitecore which is kind of the standard in this world. I would just charge the batteries up at home before going somewhere, and just use the amp for as long as it would last. I just kinda wondered how long you think the amp might run with 2 AH, maybe a little more (the batteries are various values usually expressed as 2100 or 2500 or 3200 mAH) and they are already used so I just conservatively said 2 AH. I could match 6 of them up as closely as possible but I don't think I have 6 of exactly the same kind anymore lol.

    I will probably use this amp most of the time with a good 19.5v laptop supply, and buy or build a hefty 24v DC supply like you mentioned, I was just kind of toying with the idea of making it mobile, but in the end it might be better just to make something like a Sprite with just a simple 2 ch amp for mobile use, and hey, what's more fun that building more stuff.

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    • #17
      Originally posted by Millstonemike View Post
      The amp uses one chip for the ".1" sub channel and has a fixed, sallen-key topology 2nd order LP filter with Butterworth damping. On my board, the LP F3 was 107hz. I've successfully modified that filter by replacing 2 box poly caps. In the schematic, you can see a table of possible F3s given standard value capacitors. I added a legend to the amp's picture to cross refrence with the schematic.
      Hello,

      So sorry to necro this old thread, but it's the only thread that I've found that matches exactly what I'd like to do!

      I've just purchased a Nobsound GFJ510 which seems to contain an Aiyima board inside. Similar, but a few key differences that I can see from your original post!

      I'm just curious if you'd be able to assist with the modification to this board to set the HP to around 100hz or thereabouts?

      TLDR: I've got two full range drivers with an F3 of 101hz, and I'm about to install a sub that'll be able to do around 38-200hz. I noticed that the speakers still do full duty and would certainly like to relieve them of said duty and pass that along to the sub itself. My knowledge of which caps and where is unfortunately quite lacking.

      Thank you, and again, apologies for the necro!
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      • #18
        Originally posted by modem7 View Post

        Hello,

        So sorry to necro this old thread, but it's the only thread that I've found that matches exactly what I'd like to do!

        I've just purchased a Nobsound GFJ510 which seems to contain an Aiyima board inside. Similar, but a few key differences that I can see from your original post!

        I'm just curious if you'd be able to assist with the modification to this board to set the HP to around 100hz or thereabouts?

        TLDR: I've got two full range drivers with an F3 of 101hz, and I'm about to install a sub that'll be able to do around 38-200hz. I noticed that the speakers still do full duty and would certainly like to relieve them of said duty and pass that along to the sub itself. My knowledge of which caps and where is unfortunately quite lacking.

        Thank you, and again, apologies for the necro!
        The board in the GF510, especially the front-end before the two amp chips, is different than any board I've analyzed. The only thing I can offer is this:

        Determine which chip is handling the L-R full range. Look at the chip's L-R inputs (data sheet has the pin out), and trace the inputs through a SMD capacitor to the respective op-amp outputs. Decreasing the value of the cap will increase the F3 of the 1st order HP filter - inherent in any design using decoupling caps between components where the chip has a known input resistance. While resistors are labeled with values, the caps are not. So there's not enough info to calculate replacement values to meet your needs. It would lab test and analyze endeavor (not to mention soldering SMDs).

        If your modeling the full range drivers (I presumed their sealed) try using a smaller volume - less excursion down low, hence less output. And they'll inherently take less power mating to the sub output because: (1) There's two of them - plus 6 dB output; and (2) they're likely way more efficient than the sub driver.

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