Yes, it would, in case it is a regulated linear power supply. PSR of TPA3255 is only 65dB and it is nothing to call home about. Attached is a result with regulated and unregulated linear PSU. And also the influence of filter cap value in the unregulated PSU.
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I'm sorry... but I feel the need to call this one out.
Are you legitimately claiming that you've built an SMPS, without secondary linear regulation, that can provide 275W and 50V from its primary output with a noise floor that is better than an APX555?
Please provide all your measurement settings, and an actual FFT in dBV of the output of the supply directly connected to some nominal load and the input of the AP.
I'm going to step out on a limb here and say that what you're claiming is not possible without some fudging of numbers or measurement setup. Even getting an LT3045 to measure that well is not trivial.
There are dozens of posts on here where some pretty wild claims are being made, but precious few actual measurements to back those up. Here are a few suggestions to keep people honest:
1. State what your measurement setup is, and provide a picture with the DUT connected.
2. Describe your signal chain. Any external filters, non-standard generators, loads, etc...
3. State your measurement setup. BW limitations? high pass, low pass, AC or DC coupling, weighting, EQ, balanced or SE, input and output levels, load, power output if applicable.
4. Provide your graph. Don't publish graphs in dBrA as these are difficult to compare to other graphs, or impossible if you omit the "A" definition. Any FFT published should be in dBV to avoid misleading people. If you're providing a single-metric measurement (eg. "my SINAD is 120db") then back it up with the actual measurement window showing this, and an FFT of the output under these conditions.
If we're going to try and take the high road of being "objective" in our goals and discourse, then we need to at least attempt to follow the scientific method and provide sufficient information and evidence to allow others to repeat our measurements and provide their own under equal conditions. Making very bold claims and providing absolutely no supporting evidence cheapens the value of objective measurements and severely impacts the quality of discourse.
Regards,
Owen
You could read from my measurement posted that THD+N = 0.0046% for 5W/4ohm and 20kHz BW, with the linear regulated PSU. So you can easily compare to the value that you have posted.
Yes I can, however I think you know it from ASR. It is a 30 years old regulated PSU used for instrumentation (not for audio) and I just did not have anything cleaner to test the A07 noise. Output noise of the PSU is 143uV (BW=24kHz). I am also attaching output noise spectrum of the PSU.
Tomorrow I will get the SMPS, so I am curious.
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What's the view here on how many Watt the PSU should be rated at?
The 3251 is rated at 100W @ 1THD 4Ohm /channel= 400W (-ish)
The 3255 is rated at 260W @ 1THD 4Ohm /channel= 520W (ish)
But I'm guessing I wont use a fraction of that or any speakers I'm looking at would go up in smoke.
The Connex RS series states a R&N about half that of Meanwell RSP or SE series, but if that is correct is more than I know. They do seem to be available in Europe in the 300W version, that's why I'm asking.
The 3251 is rated at 100W @ 1THD 4Ohm /channel= 400W (-ish)
The 3255 is rated at 260W @ 1THD 4Ohm /channel= 520W (ish)
But I'm guessing I wont use a fraction of that or any speakers I'm looking at would go up in smoke.
The Connex RS series states a R&N about half that of Meanwell RSP or SE series, but if that is correct is more than I know. They do seem to be available in Europe in the 300W version, that's why I'm asking.
Hi cdsgames,
So you're using a post-SMPS linear reg to achieve that noise figure. Understood. I'm still not convinced that level of output noise is possible at those power levels, so it would be nice if you could provide some details around that, specifically an FFT of the output under light load.
The absolute best regulators in the industry struggle to get down to 1.7uV of output noise and that's at a fraction of the power you're claiming (LT3045 is good for 7.5W). If what you're saying is true, then color me impressed, but a claim like that does require some evidence to back it up.
The best I've managed to achieve with linear regs at those power levels (>250W) is about 15uV of RMS noise from DC to 22kHz and that was with a quartet of LT3081 regs and quite a lot of heatsink.
Regards,
Owen
So you're using a post-SMPS linear reg to achieve that noise figure. Understood. I'm still not convinced that level of output noise is possible at those power levels, so it would be nice if you could provide some details around that, specifically an FFT of the output under light load.
The absolute best regulators in the industry struggle to get down to 1.7uV of output noise and that's at a fraction of the power you're claiming (LT3045 is good for 7.5W). If what you're saying is true, then color me impressed, but a claim like that does require some evidence to back it up.
The best I've managed to achieve with linear regs at those power levels (>250W) is about 15uV of RMS noise from DC to 22kHz and that was with a quartet of LT3081 regs and quite a lot of heatsink.
Regards,
Owen
First, I am coloring you impressed. Thx you for understanding what we have achived.
Second, I agree that some measurements are fake. I won't say anything further and let you all make up your own mind.
Third, I am not using linear regulators, but a 4 Gen capitance multiplier with 0.6v drop. I do use AP so I am rather sure that achiving 0.00012(latest) thd 1khz 5w 4r needs a psu that's very, very quiet. Battery like quiet.
As I said before Tpa3255 has no real psrr. Class d, has a " fake psrr" on Btl.Psu noise should be canceled, it is, on btl phases. However the analog signal on each phase , is modulated by direct psu noise and cannot be canceled on same btl.
Of course, by using llc power, psu ripple its not modulating analog signal. Noise floor however, definitely is ( but you can hear it less)
That's the main reason that all Tpa3255 have thd+n of 0.002 around. We improved by at least 11db.
Can you hear it? I don't know, but I will not stop trying to improve all measurement including thd,/ap, switching noise/spectrum a...and some more that I am not willing to discuss at this time.
Does it make more sense now opc?
Second, I agree that some measurements are fake. I won't say anything further and let you all make up your own mind.
Third, I am not using linear regulators, but a 4 Gen capitance multiplier with 0.6v drop. I do use AP so I am rather sure that achiving 0.00012(latest) thd 1khz 5w 4r needs a psu that's very, very quiet. Battery like quiet.
As I said before Tpa3255 has no real psrr. Class d, has a " fake psrr" on Btl.Psu noise should be canceled, it is, on btl phases. However the analog signal on each phase , is modulated by direct psu noise and cannot be canceled on same btl.
Of course, by using llc power, psu ripple its not modulating analog signal. Noise floor however, definitely is ( but you can hear it less)
That's the main reason that all Tpa3255 have thd+n of 0.002 around. We improved by at least 11db.
Can you hear it? I don't know, but I will not stop trying to improve all measurement including thd,/ap, switching noise/spectrum a...and some more that I am not willing to discuss at this time.
Does it make more sense now opc?
D
Deleted member 148505
Aiyima 7255 psu
Hello everyone!I just got aiyima a07 Amp ,also recommended by a seller (aiyima)psu which is 48v 7,5a. However my speakers are 100w rms 8ohm stereo.Do i need that kind of power from psu for 8ohm?Psu is ok, pleeeenty of power but standby 12w bugging me a bit.I had tpa 3116d2 previously with 24v brick psu and it was using only 2w in standby mode.Can somebody tell me how much power i actually need for my 100w 8R stereo speakers?Thanks a lot.
BTW i dont know if that matters but i have also aiyima T5 preamp connected, it strentghten the signal little bit as well i think..
Hello everyone!I just got aiyima a07 Amp ,also recommended by a seller (aiyima)psu which is 48v 7,5a. However my speakers are 100w rms 8ohm stereo.Do i need that kind of power from psu for 8ohm?Psu is ok, pleeeenty of power but standby 12w bugging me a bit.I had tpa 3116d2 previously with 24v brick psu and it was using only 2w in standby mode.Can somebody tell me how much power i actually need for my 100w 8R stereo speakers?Thanks a lot.
BTW i dont know if that matters but i have also aiyima T5 preamp connected, it strentghten the signal little bit as well i think..
D
Deleted member 148505
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US $24.00 20%OFF | shui yuan Audio TPA3255 2.0 Digital Amplifier Board DC24-48v Strong High Power 300W + 300W Class D o Digital Amplifier Board
shui yuan Audio TPA3255 2.0 Digital Amplifier Board DC24 48v Strong High Power 300W + 300W Class D o Digital Amplifier Board|Amplifier| - AliExpress
I just found this new cheap tpa3255. Looks good
shui yuan Audio TPA3255 2.0 Digital Amplifier Board DC24 48v Strong High Power 300W + 300W Class D o Digital Amplifier Board|Amplifier| - AliExpress
I just found this new cheap tpa3255. Looks good