Douk Audio has a new cheap PFFB amp looks interesting in that you can take the top cover off to easily change op amps. 100 bucks with a 32 volt power supply.
The Amazon listing is just plain deceptive. Their web site listing from #3 above has a table for power output:Selling the unit with a 35V5A supply and advertising "300 Watts x2", without caveat or note regarding PSUs, has got to be illegal.
The best case scenario with that 32V5A PSU will be 2x110W (4Ω, 1% THD).
Note that distortion level isn't mentioned (1% maybe?) and none reach the headline 300W figure.Power Output Table of The A5
Power Supply Speaker Impedance Rated Output Power 32V/5A 4Ω 78W+78W 6Ω 71W+71W 8Ω 65W+65W 36V/6A 4Ω 107W+107W 6Ω 100W+100W 8Ω 94W+94W 48V/5A 4Ω 120W+120W 6Ω 110W+110W 8Ω 102W+102W 48V/10A 4Ω 250W+250W 6Ω 210W+210W 8Ω 185W+185W
Hi, the Amazon page added the power output table already. Thank you for pointing out this.The Amazon listing is just plain deceptive. Their web site listing from #3 above has a table for power output:
Note that distortion level isn't mentioned (1% maybe?) and none reach the headline 300W figure.
@Douk Audio care to comment?
The power output table is there if you go looking for it, but not on screen by default. Meanwhile the headline still says "300 Watts x2" and the "About this item" says:Hi, the Amazon page added the power output table already. Thank you for pointing out this.
By the way, the distortion of the A5 is below:
4Ω, 1% distortion: 195W
8Ω, 1% distortion: 100W
Distortion: 0.002% (4Ω/8Ω, 5W)
Hope this helps.
The table that is shown by default says:300W×2 Power with Premium Components: Powered by the TPA3255 chip and premium components, A5 delivers distortion-free audio with ultra-low THD (0.002%)
The amp is supplied with a 32V 5A supply, so as supplied it can't output 300W.
Max. output power: 300W × 2 (4Ω) Matched speaker impedance: 4-8Ω THD+N: 0.002%
Personally I don't care for the FCC rules at all (both because I'm not in the US bot also because they are just bad and doesn't apply for any kind of real world use), but I do agree that having a table showing 300Wx2 and a THD+N at 0.002% is extremely misleading. Sure you might maybe be able to push out 300W with the right power supply, but _never_ at a THD+N at 0.002%, not even close.The power output table is there if you go looking for it, but not on screen by default. Meanwhile the headline still says "300 Watts x2" and the "About this item" says:
The table that is shown by default says:
The amp is supplied with a 32V 5A supply, so as supplied it can't output 300W.
To be fair almost everyone using a TPA3255 uses the 300W x2 claim without a load, distortion figure or supply voltage specified, but that doesn't make it any less misleading. They're all clearly violating the FCC amplifier rule for listings in the US.
On any large/full size amplifier the setting for a high pass filter is on the front panel if there is one.i'm not sure how i feel about the super prominent 30-250hz cut off knob on the front
i think having a permanent 30hz lowest cut is ok given most of us do not have 20-20 speakers but its a weird choice to always have that on the front - it's ok if you keep changing mains
Good comment. I’m curious to hear what @Douk Audio thinks about this, actually.To be fair almost everyone using a TPA3255 uses the 300W x2 claim without a load, distortion figure or supply voltage specified, but that doesn't make it any less misleading. They're all clearly violating the FCC amplifier rule for listings in the US.
If you look closely on the HP filter dial you will see that it says "Off" just next to "30Hz", so if you turn it all the way to 30Hz and a bit more you'll probably hear a click and then the HP filter is off.Is it true that the high pass filter is always on and cannot be turned off?![]()
Thanks for the tip, I hadn't seen that.If you look closely on the HP filter dial you will see that it says "Off" just next to "30Hz", so if you turn it all the way to 30Hz and a bit more you'll probably hear a click and then the HP filter is off.
What difference would that make at 30 Hz? Any reasonably normal speaker would only benefit from it.Is it true that the high pass filter is always on and cannot be turned off?![]()