SmackDaddies
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so long as you are using this for a desk system, you are very unlikely to average that output.At 20 watts
so long as you are using this for a desk system, you are very unlikely to average that output.At 20 watts
Does anybody know how the 3.5mm/RCA inputs work (i.e. are they just wired together)? Should you avoid connecting different sources at the same time?
That's all in the review thread: https://www.audiosciencereview.com/...ds/aiyima-a07-tpa3255-review-amplifier.18984/I already know this test... is from March 2019 )
I am talking about the AIYIMA A07, so again :
What about THD+N @5W / 4R ?
What about Sinad 5W / 4R ?
I have easily maxed out desktop amps that put out that kind of power in desktop use. Desktop doesn't mean you use them for background music. When the right rack comes in my playlist, I turn up the volume to enjoy good bass and such.so long as you are using this for a desk system, you are very unlikely to average that output.
That's all in the review thread: https://www.audiosciencereview.com/...ds/aiyima-a07-tpa3255-review-amplifier.18984/
You are in the teardown thread.
It is a Seek Thermal camera that plugs into my phone.Kindly, what thermo camera do you use ??? Thanks
According to the peripheral circuit, I would choose opa827. But I would rather changing the the peripheral circuit and make opa1612 or lm4562 work best.LM4562 would be my first choice based on op-amp rolling a CMoy back in the day.
In the CMoy thread, @JohnYang1997 recommended OPA2156 and OPA2189.
According to the peripheral circuit, I would choose opa827. But I would rather changing the the peripheral circuit and make opa1612 or lm4562 work best.
You need soic to dip adapter board anyway. So single to dual is not much to add. Opa828 doesn't improve much over 827 (especially noise) and removed some characteristics I like, eg diamond buffer output. Both of these are expensive. I would also prefer just modding peripheral circuit for lower noise.But OPA827 is a single opamp, not dual. So it would need a new PCB design. Talking about this part, which I also testem years ago, as of today I would try OPA828.
Had an epiphany this morning and recalled I have a small set of hex bits. Two of them were fitting to open the A04no, I mean a set of security bits. The one in question might be odd, but I'd be surprised if a comprehensive set of security bits wouldn't take care of things.
I have easily maxed out desktop amps that put out that kind of power in desktop use. Desktop doesn't mean you use them for background music. When the right rack comes in my playlist, I turn up the volume to enjoy good bass and such.
Regarding the statement from Quantasylum link: "Class D amps require the output filter be designed for a specific load. If you change the load, the output response will change", I've seen this trebles roll-off behaviour to more expensive Class-D amps too, loosing at least 0.5 dB @ 20 kHz. I wonder why manufacturers are not designing the output filter for 4 Ohms loads instead of 8 Ohms; this way the roll-off will be almost non-existent for 4 Ohms loads, while for 8 Ohms loads will start to roll-off a bit higher (at 24-26 kHz perhaps). I don't think amps will start to oscillate if they'll do that.@JohnYang1997 has posted the link to the excellent test. The TI board is much better than the AIYIMA.
I do like J.A.'s approach: "Even at the level of a few millivolts, unless this energy is filtered, you can never be sure that you're not actually measuring the interaction between the RF content and the test gear instead of the absolute performance of the amplifier under test (again, see the PS Audio review). Therefore, to ensure that I was measuring what I thought I was measuring, I repeated the THD-related measurements using an active sixth-order low-pass filter set to 30kHz".Actually it will probably ring a bit before rolling off at higher ohms. Random example:
Less than 0.5 dB @ 20 kHz is probably not an issue. An amplifier that measures perfectly flat till 100 kHz or more might have stability issues with high impedance loads. Of course, there are several amps that measure flat from 10 Hz till 100 kHz or more, but in the end it's all about the design I guess.Ok, wait, actually, an even better question would be why do some class-AB amps limit their frequency response like this too.
Regarding the statement from Quantasylum link: "Class D amps require the output filter be designed for a specific load. If you change the load, the output response will change", I've seen this trebles roll-off behaviour to more expensive Class-D amps too, loosing at least 0.5 dB @ 20 kHz. I wonder why manufacturers are not designing the output filter for 4 Ohms loads instead of 8 Ohms; this way the roll-off will be almost non-existent for 4 Ohms loads, while for 8 Ohms loads will start to roll-off a bit higher (at 24-26 kHz perhaps). I don't think amps will start to oscillate if they'll do that.
I am posting a simulation of the frequency response of the LC filter as shown in the TPA3255 TI datasheet. It is valid just for the BTL circuit.
output LC filter response into 4 and 8 ohm load.
Did you enter the ESR of the parts in those Bode sims?Tried to make a "reverse engineering" from the posted photos of AIYIMA A07. The filter (itself) seems to be better balanced, with less Q when damped by 4 and 8 ohm. We shall see after the real unit arrives.
View attachment 103376
Did you enter the ESR of the parts in those Bode sims?