I wonder how the board will perform paired with some 95db full ranges (W8-1772). Obviously, the output power must not exceed the speakers'
Asking so little power from this board makes me belive the distortion will be quite small.
And another question about the input caps. It seems that AA-AB32512 has an input impedance of 33KOhm (at least that what sure says here for the older version: Sure Electronics' webstore 2 x 500 Watt Class D Audio Amplifier Board Compact - T-AMP). In this case 2.2uf for input caps would be more than enough, isn't it?
Asking so little power from this board makes me belive the distortion will be quite small.
And another question about the input caps. It seems that AA-AB32512 has an input impedance of 33KOhm (at least that what sure says here for the older version: Sure Electronics' webstore 2 x 500 Watt Class D Audio Amplifier Board Compact - T-AMP). In this case 2.2uf for input caps would be more than enough, isn't it?
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They perform great at high spl speakers. The thing about the power is, short term power may exceed the rating by a lot without any damage (unless ithe driver does too much excursion), the long term power is critical though. With that high spl I doubt you'll encounter any problems power wise, you'll get 105dB with just 10W.
I got 2 of those and 2 Mean Well LRS-350-36.
One board connected to 100db 8 ohm fullranges (Fane Sovereign 12-250TC). No sign of distortion anywhere.
It has so much more control, attack and clarity than my not so cheap class ab amps. My ab amps sound slow, tired and sluggish in comparison.
Imho I don't think anyone really needs "more" than this little marvel.
Except maybe for high power subs. But I will use the IRS2092 for those.
The other board is connected to my kickbins.
I think it has some kind of soft-clipping circuit.
When raping it on my kickbins the clip led went red but no audible distortion has been present, it just sounds a little more "compressed".
When I will complete the IRS2092 this one will drive the other 2 Fanes.
On 8 ohm speakers there might be some kind of slight high boost due to the output lp filter though.
Long story short:
You can't go wrong with this one.
One board connected to 100db 8 ohm fullranges (Fane Sovereign 12-250TC). No sign of distortion anywhere.
It has so much more control, attack and clarity than my not so cheap class ab amps. My ab amps sound slow, tired and sluggish in comparison.
Imho I don't think anyone really needs "more" than this little marvel.
Except maybe for high power subs. But I will use the IRS2092 for those.
The other board is connected to my kickbins.
I think it has some kind of soft-clipping circuit.
When raping it on my kickbins the clip led went red but no audible distortion has been present, it just sounds a little more "compressed".
When I will complete the IRS2092 this one will drive the other 2 Fanes.
On 8 ohm speakers there might be some kind of slight high boost due to the output lp filter though.
Long story short:
You can't go wrong with this one.
The input capacitors can be increased in value to reduce the low frequency cutoff at the expense of some turn-on pop. I'm using one of these to drive bass speakers in a 3-way system. 10uF caps fitted across the volume PCB headers give a much improved bass response but a mildly annoying pop at power on. There may be some way to further delay startup but I haven't looked into it yet.
Selwe,
If indeed the input impedance is 33K, then 2.2uF should give textbook perfect bass extension as you say...-3dB point will be in the basement at 2Hz. Funny thing is, it seems to be a somewhat common practice to use larger value input caps than what technically ought to be required. I don't understand it, but I have seen several people say that they hear more bass this way...when they exceed the theoretical requirement.
Johnny,
If you are tired of being mildy annoyed by startup pops, you might try this solution. This simple Cap Multiplier design has been getting some attention lately, as a way to slowly ramp up power to a circuit, charging caps gradually over the course of a few seconds. I built a tiny version of it for a Class A headphone amp, and it works well...no more pops. As a bonus, it also cleans up PSU ripple. The only cost is a bit of voltage drop.
For the turn on pop I think a cheap protection board could be connected on outputs. I'm not sure though that any DC protection board would work for this kind of amp (single power supply, BTL). I've bought a UPC1237 based board from ali and it comes with one second delay start (before it connects the speakers via relays). Again, I'm not sure the DC detect function works for this amp topology.
I've waited quite a while for someone else besides sure/wondom to sell amplifier boards with the STA516/STA508 ICs and I finally found some on eBay. They are very reasonable priced and I'm extremely tempted to order the smaller one, for that price there's not much risk. I have to say I don't know anything about these amps, haven't heard them and don't know anyone who has. Does, by chance, anyone on here already got hands (erm, ears 
) on them?
YJ STA516B 2.1 320W+160W+160W 4ohm Class D Amplifier Completed board | eBay
STA508 + TC2000 2.1CH Class D Amplifier Board Amp 2*80W+160W (Beyond TPA3116) | eBay
) on them?YJ STA516B 2.1 320W+160W+160W 4ohm Class D Amplifier Completed board | eBay
STA508 + TC2000 2.1CH Class D Amplifier Board Amp 2*80W+160W (Beyond TPA3116) | eBay
I got both of them. But the TI chip is on a cheep board and it sounds not so good like the wondom. Perhaps the EVM sounds better, but cots 3 time the chineese board.
My wondom has 2,7u Mundorf caps and sounds with my tube buffer perfect.
HP
Thank you very much. I already got one Sure amp but I need 2 more channels and I thought I could maybe get away a bit cheaper.
I switched the input caps too, mine are Panasonic ones, I can confirm, the improvement is clearly audible. Maybe these boards can be easily tuned too but I think I'll instead just go for another Sure/Wondom one. Again, thank you for the information.
The input cap changes/imprives the clarity, details and if you go for a higher value, it extends the bass. If you want more 'polished' treble, bit more 'bite', modify the output filter inductors (lower inductance) since that filter interacts - like on every class D amp - a lot with the speaker impedance.
On 8 Ohm they don't have that much power. The specs say clearly the power is reached at 3 Ohm. And it's ofcourse dependent on the power supply voltage. The power supply itself got a lot to say on how it sounds too btw. At which voltage are you using your amp? What kind of PS are you using?
I also have the same amps and Mean Well LRS 36v 350w psus.
For me they sound almost perfect. With a lot of 2nd order hd, like tube amps.
If the sound is too soft for you just increase supply voltage, it will sound more "harsh" then.
Estimated output power on 8 ohms is maybe like 80-90w max. rms.
On the 36v psu should be lower.
I cannot use the full power on the Fane 12-250TC s due to possible hearing damage and even outdoor on my 6th order kick bins they deliver a lot of punch before clipping.
For such a small amp it gets stupid loud. Also I like the "soft-limiter/clip".
It is subjectively louder and has more attack/precise punch than my expensive ab amps rated at 125w/8ohms.
No idea what's the "problem" here.
I have them both, or at least the "Gremlin" variant of AA-AB32313 with a 2.2 uF PP input capacitor, And the TPA3255 EVM board.
Both amps have a linear power supply, the Sure board around 36V and TPA3255 48 volt power supply.
Using them with the same source and 8 ohm speakers it is safe to say they are quite different. The EVM board are very dynamic, clean sounding in the whole audio spectrum, a fair bit of bass, nothing really stands out.
The Sure board is the ultimate party machine, much more dynamic sound, huge amount of bass, a warm sound, and little bit of frizzle to the treble. I guess I could modify the board to behave better, a project for another time.