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New Dual TPA3255 Module + PFFB / Fully differential / OP amps DIP8 @ Great price
eric00886
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I recall that you’re a total expert on the TPA3255! I’d love to get your thoughts on this board. The price is definitely very cheap, but it seems like not many people are discussing it. Thanks!
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I am a curious EE with some decent test equipment (Quant Asylum QA403) and I have spent way too much money buying and testing multiple TPA3255 boards from Amazon and Aliexpress. Some are capable of impressively low distortion provided the right power supply is used at the optimum voltage. All I have tested have significantly higher distortion at 48 volts compared to 36-40 volt range. They also run much hotter. The quality of the power supply is also important. MeanWell LOP power supplies are among the best but they are also more expensive than most. The advantages of the MeanWell LOP are small size, power factor correction, good regulation, and ability to tweak the voltage output with a potentiometer. You will pay somewhere between $60-120 for MeanWell LOP supplies with between 300-600 watts depending on model and where you buy it. Then you still have to factor in cost of a decent case and cooling fans if you are going to run these amplifiers at high power.
This is all doable and I have done it to replace the guts of a B&K AV6000 home theater 6 channel amplifier that died.
The thing is, I could have purchased 3 Aiyima A07 Max amplifiers for less than I spent on DIY for equivalent performance. For that matter, I could have gone with Fosi V3 Mono amps and still come out ahead if purchased on sale. I picked up 2 V3 Mono amps last year for about $75 each. A MeanWell LOP-600-48 would easily drive 3 V3 Mono amps so would need 2 power supplies.
Long story short, I think I am done experimenting with DIY TPA3255 boards. It was fun but not economically wise. The other factor to consider is that counterfeit boards that look like higher quality boards also exist and it is hard to know what you are buying on Aliexpress. A very knowledgeable DIY designer on diyAudio forum named Nolperi built a beautiful 6 channel home theater amplifier using SAMP-100 TPA3255 boards that he modified to have PFFB. Once built, he noticed that some boards had great peformance but 2-3 of them did not. On closer inspection he determined the underperforming boards are very likely counterfeits. One had a solder blob where there is supposed to be a chip capacitor in the TI reference design.
For future DIY projects, I will spend a bit more and buy boards from guys like @eclipsevl and @uriy-ch who have some very interesting designs with DSP chips on the amplifier board. Their designs are not TPA3255 based. They use other TI chips that take direct digital inputs and do not need a DAC between the DSP and the amplifier chip. The engineering is solid and both document their designs well - far superior to anything on Aliexpress. They fix bugs when they find them and publish what they did to improve the board design. Did I mention they both have DSP on board allowing the user to do parametric equalization and active crossover designs? Both sell 4 channel designs for approximately $200 plus tax, shipping and tariffs if they apply. @eclipsevl has written custom user interface software that enables setting the DSP chip without having to understand Sigma Studio design software. His software interface is very similar to what miniDSP supplies but his work is original. Lastly, both inventors provide outstanding technical support over on diyAudio forums. They respond quickly to questions.
At this point, I have spent well over $2500 to buy and test Aliexpress TPA3255 boards, Aiyima amplifiers, Fosi amplifers, 3E Audio amplifiers, and various power supplies I also have purchased boards from both @eclipsevl and @uriy-ch. I could have purchased a high end Class D amplifier for that money but I do not regret the knowledge gained.
Bottom line for me is that Aliexpress is a crap shoot and not worth it in the long run. My time is worth something and I would much rather spend it on DIY products that are well supported, have documented performance and better quality control.
This is all doable and I have done it to replace the guts of a B&K AV6000 home theater 6 channel amplifier that died.
The thing is, I could have purchased 3 Aiyima A07 Max amplifiers for less than I spent on DIY for equivalent performance. For that matter, I could have gone with Fosi V3 Mono amps and still come out ahead if purchased on sale. I picked up 2 V3 Mono amps last year for about $75 each. A MeanWell LOP-600-48 would easily drive 3 V3 Mono amps so would need 2 power supplies.
Long story short, I think I am done experimenting with DIY TPA3255 boards. It was fun but not economically wise. The other factor to consider is that counterfeit boards that look like higher quality boards also exist and it is hard to know what you are buying on Aliexpress. A very knowledgeable DIY designer on diyAudio forum named Nolperi built a beautiful 6 channel home theater amplifier using SAMP-100 TPA3255 boards that he modified to have PFFB. Once built, he noticed that some boards had great peformance but 2-3 of them did not. On closer inspection he determined the underperforming boards are very likely counterfeits. One had a solder blob where there is supposed to be a chip capacitor in the TI reference design.
For future DIY projects, I will spend a bit more and buy boards from guys like @eclipsevl and @uriy-ch who have some very interesting designs with DSP chips on the amplifier board. Their designs are not TPA3255 based. They use other TI chips that take direct digital inputs and do not need a DAC between the DSP and the amplifier chip. The engineering is solid and both document their designs well - far superior to anything on Aliexpress. They fix bugs when they find them and publish what they did to improve the board design. Did I mention they both have DSP on board allowing the user to do parametric equalization and active crossover designs? Both sell 4 channel designs for approximately $200 plus tax, shipping and tariffs if they apply. @eclipsevl has written custom user interface software that enables setting the DSP chip without having to understand Sigma Studio design software. His software interface is very similar to what miniDSP supplies but his work is original. Lastly, both inventors provide outstanding technical support over on diyAudio forums. They respond quickly to questions.
At this point, I have spent well over $2500 to buy and test Aliexpress TPA3255 boards, Aiyima amplifiers, Fosi amplifers, 3E Audio amplifiers, and various power supplies I also have purchased boards from both @eclipsevl and @uriy-ch. I could have purchased a high end Class D amplifier for that money but I do not regret the knowledge gained.
Bottom line for me is that Aliexpress is a crap shoot and not worth it in the long run. My time is worth something and I would much rather spend it on DIY products that are well supported, have documented performance and better quality control.
eric00886
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Haha I totally get what you mean. AliExpress and Taobao? Pure gambling, man! You're completely at the mercy of luck. Mind you, I'm not dissing them—I only get small toys or cheap gear on there to mess around with anyway. And honestly, Taobao is usually way cheaper than AliExpress.
Speaking of fake or sketchy parts, it reminds me of this story from way back in 2008. I was on a business trip around the Chegongmiao Industrial Zone, out getting a quick snack. Their sales rep was outside taking a smoke break, so we ended up shooting the breeze. Out of nowhere, he casually tells me they could order one truckload of real Nichicon caps and somehow ship out three! Pretty wild.
As for those TPA3255 boards on Taobao, they’re like $10 to $25 bucks, so honestly, they're fine for what they cost—just cheap toys after all. Like locals over there say, At that price, what more do you want? A free bicycle? But still, I did run into three weird little quirks worth sharing: First, a buddy of mine reckons some boards are sneaky and swap in a TPA3221. Second, another friend caught that the step-down IC maxes out at +40V, though swapping it out solves that. But the biggest kicker? A seller I trust reckons suppliers are stuffing these boards with pulled parts from old gear.
I personally prefer using the MeanWell HRP-300N3 for power. But even though MeanWell is a Taiwanese brand, it still sets me back nearly US$100—way more expensive than the TPA3255 modules I got off Taobao!
By the way, have you ever tried the xrk971 TPA3255 module? I only stumbled upon that project recently. Hand-soldering SMD parts doesn't scare me at all, but sourcing all the individual components sounds like a total pain.
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I haven't tried the xrk971 TPA3255 module but that seller looks like someone you can trust. I see that only the circuit board is available right now. I also see that it is based on the Texas Instr reference design (so are the Aliexpress boards). Advantage I see with xrk is you can source your own parts and be assured of the quality.
Downside, is you can still purchase some very good finished 3255 amps from Aiyima and Fosi Audio for reasonable prices. Aiyima A07 Max regularly goes on sale for $60-70 range. Hard to top that with any DIY design. For my money, if I am building a DIY amp, i am using one of the boards I mentioned above that also include very capable DSP chips. They are not 3255 chip based. They use a different TI amplifier chip that takes direct digital output from the Analog Devices ADAU1452 DSP chip.
eric00886
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I'm actually pretty interested in that xrk971 TPA3255 project, but sourcing all the components is such a pain. Take SMD resistors for example—you can't just buy the exact count you need. You end up with a mountain of dead stock just for one project.
I completely agree with your point about brand-name gear, though. You've really got me rethinking things: for the cost of the xrk971 PCB plus shipping, I could already buy a pretty solid finished amp! Going with a commercial amp is just way more practical, plus it dodges all those potential bad designs or sketchy, defective parts. I guess I'm really just driving myself crazy all for the sake of 'fun'!
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FYI, here is THD, SNR and other data for Aiyima A07 Max at 6 watts power output. Ignore the 'spikes' below 1000 Hz. They are power line noise that my Quant Asylum picked up and not a problem with the Aiyima amp. The noise spikes above 8000 Hz are also not relevant. Some or all are due to the output stage switching frequency which is far above human hearing and above the sampling rate of the Quant Asylum analyzer. This is known as 'aliasing' and not a problem with the amplifier. I have built a filter to block those noise spikes since I ran this test. Bottom line is the SNR and THD for this amp are very good and I doubt any DIY 3255 board can do significantly better. More to come ...
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Power line noise and aliasing are artifacts of my test setup and not indicative of amplifier performance. I have since taken steps to improve my test bench. I am a EE with more than 50 years of test and evaluation experience with aerospace electronics. Audio is my hobby. My point is that my test data does not reflect the absolute best performance the amplifier can deliver but it is still very good.
This data is also relevant for comparing commercially available amplifiers to DIY boards. Same test conditions for both.
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Data for ZK-6002 TPA 3255 amplifier. This also is considered one of the better DIY boards. SNR and THD are not bad but still not as good as the Aiyima A07 Max under the same test conditions. I used an Aiyima 48 volt 5 amp power supply for this test - same power supply used with A07 Max.
I am looking for reliable high quality ADAU1452 DSP based boards, ideally lots of I/O channels
ADAU1445/ ADAU1466/ ADAU1467 even better if FIR required
With enclosure available would be nice.
I don't mind the amp chips being built in, but must be preamp-out as well if some channels need moar Watts.
3e Audio? Tinysine?
Actual purchase links would be appreciated
ADAU1445/ ADAU1466/ ADAU1467 even better if FIR required
With enclosure available would be nice.
I don't mind the amp chips being built in, but must be preamp-out as well if some channels need moar Watts.
3e Audio? Tinysine?
Actual purchase links would be appreciated
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Nothing like that in the DIY world yet. As far as finished products, Helix by Audiotec Fischer makes several DSPs with these features but cost is high. I purchased a Helix DSP Pro MK3 earlier this year from an offshore provider and it still cost me $900 after tariffs. If you want to get into their product line at a lower cost, look for used or closeout M4 DSP or M6 DSP amplifiers. They are no longer made but can be found at attractive prices. They have 4 and 6 channels of amplification respectively rated at 100w/channel. I am fairly certain they are using TI or Infineon class D amplifier chips. They use ADAU1452 DSP chips. They have 10 DSP channels if I remember correctly.
miniDSP also makes products with this capability but once again, cost is high thanks to tariffs and inflation.
Tell
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You could combine any TPA3255 board with a Raspberry Pico with DSPi flashed on it and some PCM5102 DACs. You won't have FIR thought, but otherwise it's a very competent DSP!
Yes, my question is for when FIR is indeed required.
I dunno from soldering but wonnadesedays I guess I'll bite that bullet
eric00886
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Might be way easier to just get a friend to do it for you.
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FIR stands for Finite Impulse Response. This is a type of digital filter that has zero phase shift on the signal(s) being filtered for crossovers. The more common digital filter used is Infinite Impulse Response or IIR. Pros and Cons for IIR are:
- Pros: Highly memory-efficient and computationally cheap; can sharply match classical analog filter designs (like Butterworth or Chebyshev) with very few coefficients. [1, 2]
- Cons: Exhibits non-linear phase response (delays signals differently based on frequency); carries a risk of becoming unstable if feedback coefficients are set improperly.
