The differences in positive peaklevels for each wave maybe, Vpp. But if it can be scope itself or probes it isn't informative to show that picture too.
The "school"board, by swedgin, and his distorted wave, was that probes too ? I remember seeing ampboard with vias between small decoupling capacitors and tpachip and also reading or seeing evaluation about possible FCC aproval problems, a via in that location or like that, was a problem I believe, but half sleeping now🙂
The "school"board, by swedgin, and his distorted wave, was that probes too ? I remember seeing ampboard with vias between small decoupling capacitors and tpachip and also reading or seeing evaluation about possible FCC aproval problems, a via in that location or like that, was a problem I believe, but half sleeping now🙂
Didn't we looked for the fact that RC-decoupling isn't influence/change/alter DC-offset?
RC-decoupling does not have an influence. From what can be seen, RC-decoupling is lowering noise-density/noise on that rail, also shown.
So i will do this tests again with a proper scope.
For sure, these effects can be different for a chinese-made board.
Refering to the plots here:
http://www.diyaudio.com/forums/class-d/237086-tpa3116d2-amp-850.html#post4549993
These aren't distorted waves but noise on a supply rail. The "needles" on plot 1 are indeed "glitches".
Having vias on high dI/dT rails/loops always do radiate. (Everything radiates is some way)
RC-decoupling does not have an influence. From what can be seen, RC-decoupling is lowering noise-density/noise on that rail, also shown.
So i will do this tests again with a proper scope.
For sure, these effects can be different for a chinese-made board.
Refering to the plots here:
http://www.diyaudio.com/forums/class-d/237086-tpa3116d2-amp-850.html#post4549993
These aren't distorted waves but noise on a supply rail. The "needles" on plot 1 are indeed "glitches".
Having vias on high dI/dT rails/loops always do radiate. (Everything radiates is some way)
I looked for confirmation that the R part is indeed responsible for huge increase in DCpeak levels in output of ampboard, as I seemed to find too. Posted scope pics by you seem to confirm that possibly, even without RCfilter. ~29Wrms isn't close enough to spec to assume there isn't DC imo, the volts I keep getting when trying to calculate aren't millivolts for possible DC levels on output there, they seem much higher than my ~700mV peak.
The tiny increase of noise, higher Vpp, with the RC, you showed with shorted inputs is also opposite what you wrote and opposite of what expected with radiating bypass over R, but that level would not worry me, very expensive hifi has those levels, it is the peak DC with output higher than some dcprotection circuits in expensive hifi that do worry me.
The tiny increase of noise, higher Vpp, with the RC, you showed with shorted inputs is also opposite what you wrote and opposite of what expected with radiating bypass over R, but that level would not worry me, very expensive hifi has those levels, it is the peak DC with output higher than some dcprotection circuits in expensive hifi that do worry me.
Where does the plots confirm, that additionally R is responsible for increased DCpeak levels in the output? Can you point that out please?
And what do you mean with the last "RCfilter"?
I just guessed before measured, not stated/sayed it is. 🙂 Guessing wasn't right at this point.
Uhm, from the plots, noise is lower with RC than without.
So what level do you say is "close enough to spec"?
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I wasn't here for months and Mord and irribeo are still arguing.
I recently ordered this board and would like to hear some opinions about that item:
TPA3118 PBTL mono digital amplifier board 1X60W 12V 24V POWER AMP-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
I recently ordered this board and would like to hear some opinions about that item:
TPA3118 PBTL mono digital amplifier board 1X60W 12V 24V POWER AMP-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Please let us know your opinion on this amp board after audition. I was thinking about getting it when irribeo posted the link sometime back.
Regards,
LOL - Mord & Irrebeo. 🙂
Those amps look very cute. How can you buy just one? I will order maybe 4 as I usually need 4 channels for an active speaker.
Ok, 4 of those 3118 PBTL units on the way...
I will report how they sound. They really should be discussed in 3118 thread.
I will report how they sound. They really should be discussed in 3118 thread.
Output capacitors are 0603, and I've got my suspicion they're X5R's in order to get a 35/50V rating assuming they're 0.68uF. Which means at their operating point, they sure as heck aren't 0.68uF... I've also got my doubts that those output inductors can handle 6+ amps of output current without the L dropping out.
I wouldn't call it "audiophile", but it's probably perfectly OK for PA use or a small toolbox-boombox or whatever.
@xrk971
Looking forward to your opinions. Thanks! This board looks really small in size.
Regards,
They are indeed small about same size as a 35mm film negative. Gmarsh is probably right about current limits of inductor and caps perhaps not up to snuff. But probably fine for a compact kitchen speaker. Although we might be surprised with their performance. For $8, is a no brainer 🙂
Is there any 2.1 amp out there that have variable crossover that works?
Planning to run a sub crossed at 80Hz.
Planning to run a sub crossed at 80Hz.
I just built these for my kitchen speakers. Probably cannot take 60w but I will be using 19v SMPS brick and 8R speakers so 25w is probably what is all I will need clean.
X-LS Classic kit
These are a great value.
It's just the way X5R/X7R and other capacitor dielectrics are. The stated capacitance is with zero volts applied, and the capacitance can drop anywhere from 30% to 90% at rated voltage. There's a fair bit of documentation scattered around the internet on it:
http://www.niccomp.com/help/VoltageCoefficientofCapacitors-032012-R1.pdf
In the case of this amplifier, if the capacitance of the output filter is changing with the output voltage, the frequency/phase response of the filter is changing dynamically along with it causing distortion.
Ah okay, I thought that only happened with DC applied. C0G or NP0 wouldn't be any better for this right? Only more stable with temperature change. Do you have a BoM for your Wiener board? That would help me greatly with knowing where to use which type cap.