Good catch. I like the idea of 2.1 with DAC. I wonder if the DAC OPAMP can be switched out for a better chip?"
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same thing on ebay: 2014 Newest TPA3116D2 2 1 High Power HiFi Digital Power Amplifier 50W 50W 100W | eBay
I just don't like they charge too much for the postage, probably will wait for some other sellers who can do free postage.
I just don't like they charge too much for the postage, probably will wait for some other sellers who can do free postage.
This is a message for XRK971 as well (I know he loves DSP)
Hi Rhing,
Thx for this interesting measurement.
I understand you measured a sub system distorstion.
In modern days, most sounds are digital, and we have signal process.
And we have to have a look on the complete system, including signal process.
In other words, I can have a sub system with 200% THD I can correct with DSP and vice versa, I can have a sub system with with 1% THD I can't correct with DSP because the THD is not signal dependant.
Do you have ways to measure the predictability of this sub system?
Regards,
Christian.
Coincidence but with a meter I also measure 0.14% noise when volumepot is in position that was 1 watt into 8 ohm load 1000hz. With a 5 ohm load this drops to 0.04%. Funny, probably just funny.
Yeah I'm thinking of getting rid of the electrolytics on the input completely, but getting the caps connected to + and - input pins to match capacitance is difficult due to the layout.
I have some nice 3.9 uF and 10uF film capacitors I want to place on the + input pins but there is little space to match on the - pins.
If I want to get them to match, for those big values, film caps will not fit on this board easily. (Maybe WIMA MKS2, which offer up to 10uF in 5mm Lead spacing, but those are expensive and not easy to find other than mouser)
Could I possibly throw a film on the + and maybe a ceramic or tantalum on the - ?? Not sure I understand the dangers of those choices lol
Would be good to compare rhing's results with the graphs in TI's datasheet [which BTW, makes interesting reading]; but more info required: actual voltage to the amplifier, gain setting, test impedance ... as detailed on TI's graphs ... & in reality, the tests would need to use gain, voltage, impedance etc parameters to match those in TI's datasheet & not vice versa, to be of much use as a comparison.
However, with a degree of interpolation & guessing, it's possible to glean something from the rhing numbers vs TI data
IMHO, it could well be that the high $ mods don't contribute much, if the analysis were apples for apples
Maybe rhing could arrange with TI to lab test his Formula 1 Blue/Black+Astron against their EVM board ... that would be the proof in the pudding
But obviously a good time was had doing the mods, so what the hell ... 🙂 ... & if one hears a difference for the $s spent, that's even better
I just ordered one of these (same model, different seller item #121452305142) from Ebay - I'm not intending to tweak it yet, got it as a picnic system to drive an old Sub and some satellite speakers I have kicking about for outdoor battery powered use. Being able to dial in the sub crossover frequency (between 80 - 500hz it says) and relative volumes of the sub/stereo sections make this particular model look neat.
The ebay listing doesn't say if it is a full crossover HP and LP filters or just LP on the sub.
I was going to get the bare board version, but wimped out and got the full enclosure version, buying the enclosure and binding posts would all add up anyway.
Not really DIY yet, but I'll report how this goes when I get it.
eBay link is broken. In general, the 2.1 amps don't have a real XO. The stereo channels play full range and the sub plays with a low pass filter that despite what they say, does not really have an adjustable Low pass freq. It is more like the slope of the low pass filter changes. However, it can sound nice and may be a good choice. Just don't expect the amp to have a real adjustable XO freq.
Any reason I shouldnt buy the YuanJing version / copy of the audiobah green board?
Seems silly to pay 3x as much for the audiobah when they look identical
Seems silly to pay 3x as much for the audiobah when they look identical
I provided the ebay item number, which should show up easy in the search, for me it pops up at 12V 50WX2 100WTPA3116D2 2 1HIFI Digital Subwoofer Amplifier Verst Finish Product | eBay
Its just for a outdoor picnic system using some old car speakers and a car sub so may be just fine, but I did order that one as it looked newer and gave more specific details than all the other different 2.1 boards on ebay - I was hoping the NE5532 opamps means it has a bit more of an active crossover implemented. Anyway the unit is on its way from China now, I'll do some measurements when I get it.
I hope to test the stock sure tpa3116 and my modded sure tpa 3116 through an oscilloscope this wednesday. And post the results here.
Good find, good price too, with free shipping. I also just found for a few dollars less and free ship:
2.1 HIFI Exquis digital integrated amplifier TPA3116D2 50W+50W+100W(bass) max without power supply-in Amplifier from Electronics on Aliexpress.com | Alibaba Group
Some buyer left its feedback, saying:
"The left is the stereo volume control The middle is not the subwoofer frequency adjustment. It's subwoofer volume. Right is not Subwoofer volume control. It's main volume. No the subwoofer frequency adjustment."
So I'm not too sure about that sub frequency adjustment... be careful. But I don't think there are any better alternatives out there.
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my english is not good enough to really understand what you mean by 'slope'.
but my guess is, that you mean 'steepness' measured in db/octave.
i only once had a cheap 'adjustable ne5532 crossover' (or whatever opamp was used) in my hands.
i identified a simple sallen&key 12 db/oct low pass.
those are easy to design with adjustable xo-frequencies with the use of a single stereo-pot.
my guess is, that those 2.1 boards have something like this onboard.