I don't know if I'm more knowledgeable about class D amps in general, I doubt it. But the TPA311x series I have studied a lot.
THD does have an effect on sound quality for sure but the harmonic distortion distribution is much more important than the total harmonic distortion. This is evident for anyone who has ever listened to a tube amplifier which generally has much higher THD than any class D/solid state amp. It's also worth noting that the THD of almost any amp is many times lower than the THD of almost any loudspeaker driver they will be connected to so getting the lowest possible THD shouldn't be a design goal in itself. It's merely one aspect.
The TPA311x series seems to hit a "sweet spot" around 21V. Above they start to sound stressed. Below you miss a little "umpf". This is purely my subjective opinion but it is easily testable by anyone. Please make sure to use a dB-meter to ensure output level from the speakers is the same for all settings otherwise that will mess up the result. If I was to point to a specific cause for this I would guess it to be thermally induced stresses in the output transistors and the output filter inductors without knowing for certain.
If you go to this page : ~ Scanned and cleaned up Wireless World Articles ~ and then scan down for 'May 1978' you'll find an interesting article which deals with this question, based on solid research (listening tests).
For those averse to technical papers, a key take-away is that listening results with amplifiers don't correlate with their THD measurements.
I don't know if I'm more knowledgeable about class D amps in general, I doubt it. But the TPA311x series I have studied a lot.
THD does have an effect on sound quality for sure but the harmonic distortion distribution is much more important than the total harmonic distortion. This is evident for anyone who has ever listened to a tube amplifier which generally has much higher THD than any class D/solid state amp. It's also worth noting that the THD of almost any amp is many times lower than the THD of almost any loudspeaker driver they will be connected to so getting the lowest possible THD shouldn't be a design goal in itself. It's merely one aspect.
Thank you for the clarification. You are right, the tube amp example is bang on - it seems that our ears are more tolerable to even order harmonics than odd order ones (or is it the other way round). Well designed tube amps typically has ~1% distortion, which is huge as compare to most solid state amps. Thank you for reminding me the "worst offender " of the audio chain - the speakers. As you pointed out, their distortion easily overshadow any of the other associated components
The TPA311x series seems to hit a "sweet spot" around 21V. Above they start to sound stressed. Below you miss a little "umpf". This is purely my subjective opinion but it is easily testable by anyone. Please make sure to use a dB-meter to ensure output level from the speakers is the same for all settings otherwise that will mess up the result. If I was to point to a specific cause for this I would guess it to be thermally induced stresses in the output transistors and the output filter inductors without knowing for certain.
Interesting "observation", may be I should switch the PS back to 19V
Regards,
THD does have an effect on sound quality for sure but the harmonic distortion distribution is much more important than the total harmonic distortion. This is evident for anyone who has ever listened to a tube amplifier which generally has much higher THD than any class D/solid state amp. It's also worth noting that the THD of almost any amp is many times lower than the THD of almost any loudspeaker driver they will be connected to so getting the lowest possible THD shouldn't be a design goal in itself. It's merely one aspect.
Thank you for the clarification. You are right, the tube amp example is bang on - it seems that our ears are more tolerable to even order harmonics than odd order ones (or is it the other way round). Well designed tube amps typically has ~1% distortion, which is huge as compare to most solid state amps. Thank you for reminding me the "worst offender " of the audio chain - the speakers. As you pointed out, their distortion easily overshadow any of the other associated components
The TPA311x series seems to hit a "sweet spot" around 21V. Above they start to sound stressed. Below you miss a little "umpf". This is purely my subjective opinion but it is easily testable by anyone. Please make sure to use a dB-meter to ensure output level from the speakers is the same for all settings otherwise that will mess up the result. If I was to point to a specific cause for this I would guess it to be thermally induced stresses in the output transistors and the output filter inductors without knowing for certain.
Interesting "observation", may be I should switch the PS back to 19V
Regards,
I guess the equipments that measured distortion work in a very different way as compare to our ears. The fact that human has preference on the sound they hear further complicate things too - thus the term "psychoacoustic effect"
Regards,
You can connect the output of a pre-amp straight to the input of the TPA3116 stereo board. I'm using ma Najda card as a pre-amp/DAC conected to the L/R pin used by the volume pot on the PCB.
That mirrors my impression which leads me to think the cause is in limitations of the chip itself. Most likely in the output stage.
True. Even order harmonics (or in musical terms odd order overtones) especially the 2nd and 4th order is more tolerable to the ear because they are exact doubling and quadrupling of the fundamental. However, adding a tiny amount odd order harmonics (compared to the even ordered) especially 3rd and 5th order adds fullness to the sound, at least for a listener accustomed to the traditional European school of musical scale, due to those harmonics being the frequencies of the harmony notes of a full 3 note major chord.
Absolutely same experience with my MA Alpair 7.3, connected directly to the amp.
Strong bump at starting up. Now I use to regulate the pot towards low volume to minimize the effect, but I can't get rid of it at all.
On my system if i plug the 24v to the board after having powered on the PSU, I have no bump with volume pot removed.
Does anybody know what (physical and electrical) size inductors are mounted on the standard YJ board?
I have ordered one and I am planning to try some other inductors. Not because I want the best sound possible, but because the board is going to be mounted in a see-through case and it's gonna be a hell of a lot cooler with other inductors...
I have ordered one and I am planning to try some other inductors. Not because I want the best sound possible, but because the board is going to be mounted in a see-through case and it's gonna be a hell of a lot cooler with other inductors...
22 uH Shielded square type SMD 12x12x7mm - Sumida CDRH127 or alike
methinks stock ones are nice. unshieled are way cooler indeed but could degrade EMI/performance
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This is what I do now. I just turn the volume off when I'm done. I do worry about this though if I end up using this or another amp on a tweeter in an active system. My miniDSP also makes a pop (on shut down). Is a protective cap a prudent thing to use?
Kyle
Sure, I guess I could go that route but when I used a preamp with my Topping T-amp, it was kind of difficult finding the sweet spot on the volume pot on the Topping: at full the sound was way too compressed; at 12:00 it was too recessed. I found 2:00 to be the best, but it did vary with recordings and it got tiresome having to always adjust. So would taking out the volume pot on the TPA3116 help in this regard?
Maybe we could use the Mute feature. It must kill the output from the chip.
FYI.... The last YJ 3116 board I received has a few different components (main electrolytics and filter caps) It also has a thinner PCB ( 1.52mm vs. 1.73mm that the first 6 boards I received had)
