5th element
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High H3 in these amplifiers is usually related to poorly chosen output indicators or incorrectly chosen coupling caps. Read non C0G/NPO or electrolytic.
I trust (whatever that’s worth) that generally speaking, since I bought it from Douk’s store in AliExpress (not a different store there) that the product is legit and not a counterfeit or knockoff. That said, I checked the circuit board of my unit and saw that I have V1 instead of the V2 in Amir’s photos. So there might be some differences.be careful of version , special ali version / some chanel sale
for exemple 6 cd external cd writer sold as new on amazon , 6 different seller and model , ALL have inside old writer ..after teardow and review
i buy a product on amazon , seller amazon , official product , amazon version china made , THE SAME product in big shop near me : france made
Is this a real problem or a theoretical problem? The graphs you quote show a typical spray of higher order harmonics similar or better than the non-PFFB cheap amps you compared them to, at least at 1KHz. While it may be worse at higher frequencies, are we really worried about 5th order harmonics of a 15KHz signal?
Hey J, you have a V2. Mine is a V1. I wonder what changed?Amazing how reasonably priced basic amplification has become, thanks for the time in testing.
Pics;
View attachment 435614
Note: This image shows a (unnecessary) op-amp change;
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JSmith
@amirmReserved for @AdamG to kindly post the specs.
Manufacturer Specifications:
View attachment 435591
Link to product details webpage:
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Douk Audio A5 TPA3255 Stereo Amp HiFi Audio Class D Amplifier High-pass Filter
Features HiFi Sound with Adjustable High-Pass Filter: This TPA3255 amplifier features an adjustable high-pass filter (HPF) 30-200Hz to refine mid-high frequencies while minimizing low-frequency interference. Perfect for bookshelf or passive speakers, it enhances clarity and creates a dynamic...doukaudio.com
It's either pointless or potentially detrimental, see this thread for more discussion;didn't recommend rolling the op amps? Why not?
Higher voltage would increase power for > 5 ohm (e.g. 8). Since vast majority of speakers are 4 ohms or lower, higher voltage won't do you much good, yet it will increase power consumption. Higher current would produce more power for < 5 ohm. So ideally you would stay with 32 volt but higher current. Either way, it will produce more power until thermal shut down occurs, or it gets damaged.2) You tested this w 32v/5a and not the larger 48v/5a or 48v/10a. I get that w the larger power brick... more heat will be generated if you push this amp... and I suspect that you could burn it out... That said... I still have to ask... if you got the larger brick... how would that effect your tests?
Ok... so how do you classify the low end, cost effective class D amps manufactured in China?It's either pointless or potentially detrimental, see this thread for more discussion;
Changing opamps is not the way to tailor ones sound.![]()
Serious Question: How can Op Amp rolling improve the sound of an already well measuring device? Are that many confused? (Master Thread)
On OP-Amps and Op-amp rolling Another contentious topic. Manufacturers of DACs and Amps often socket op-amps to allow people to swap them with different types, with the aim of improving the sound - or getting a different “sound signature” (Whatever that might mean to you). We get it. It’s...www.audiosciencereview.com
Further, please don't use that term here, thanks;
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Let's Avoid the Term Chi-Fi
I often see the use of the term "Chi Fi" to describe audio products from China. I see the intention and don't think anyone is trying to be racist and what have you. Still, I like us to show the highest respect to products from around the world. As avid readers of this forum know...www.audiosciencereview.com
JSmith
Gotcha, so then there's no difference in your test results.Higher voltage would increase power for > 5 ohm (e.g. 8). Since vast majority of speakers are 4 ohms or lower, higher voltage won't do you much good, yet it will increase power consumption. Higher current would produce more power for < 5 ohm. So ideally you would stay with 32 volt but higher current. Either way, it will produce more power until thermal shut down occurs, or it gets damaged.![]()
In looking at some of the posts on one of the threads...It's either pointless or potentially detrimental, see this thread for more discussion;
Changing opamps is not the way to tailor ones sound.![]()
Serious Question: How can Op Amp rolling improve the sound of an already well measuring device? Are that many confused? (Master Thread)
On OP-Amps and Op-amp rolling Another contentious topic. Manufacturers of DACs and Amps often socket op-amps to allow people to swap them with different types, with the aim of improving the sound - or getting a different “sound signature” (Whatever that might mean to you). We get it. It’s...www.audiosciencereview.com
JSmith
Since vast majority of speakers are 4 ohms or lower
In modern home audio systems, 8-ohm impedance is the most common for loudspeakers, while 4-ohm speakers are less prevalent.
There will definitely be a difference with a different power supply. See below from the Douk website. The biggest difference is going to be the amount of heat generated. While the power gains look impressive on paper you need to double power to get 3 dB more SPL. The fact that the company sent in a 32 Volt supply should tell you something. When buying an amp engineered to save every possible penny in general it is not a good idea to push them hard. Use them as designed and enjoy them for what they are.Gotcha, so then there's no difference in your test results.
(I didn't see a 32v/10A option.)
Sorry, Let me rephrase.There will definitely be a difference with a different power supply. See below from the Douk website. The biggest difference is going to be the amount of heat generated. While the power gains look impressive on paper you need to double power to get 3 dB more SPL. The fact that the company sent in a 32 Volt supply should tell you something. When buying an amp engineered to save every possible penny in general it is not a good idea to push them hard. Use them as designed and enjoy them for what they are.
View attachment 436518
ChatGPT hasn't measured 300 speakers. I have. And I note the real, minimum bass impedance. That number almost never, ever matches the specs manufacturers publish. Their numbers are essentially random is best ignored since no speaker has constant impedance anyway. Here is one of many examples:You've been saying this quite a lot, and I'm curious about it, since it doesn't mesh with what I'm seeing. I think 8 and 6 ohm speakers are as common, if not more. I don't have any statistics on this, does anyone? ChatGPT thinks that 8 ohm is the most common:
That is also a bogus setting. UL testing has limit on maximum heat generated during a special test. These multi-channel AVRs get too hot with 4 ohm in that test, even though they are fully capable of going down to that impedance. To wit, every AVR I have tested has had no problem producing power at 4 ohm. Indeed that is the main impedance for most of my tests. If there is a setting for 4 ohm, be sure to NEVER set it to that as the AVR will then limit its power output as to not risk failing UL test.I know that the last three or so AVR models I owned required 6 ohm or above
I would definitely try it but if you do make sure to do it right which as you say means you will need 2 amps in order to do fast switching. The most important part is level matching with a sine wave and a volt-meter (not by ear). You also need to set up a way to switch back and forth quickly and an assistant that can do the switching without any "tells" to help you figure out which is which. If you do it like this I am pretty sure your audio life will be changed forever and you will realize most things you read on the internet are not true. It is not that people are liars or imagining thing it is called "bias" and all humans no matter how rational are affected by it. The only way to know for sure is to test blind and level matched.Again, I haven't tried it. But w so many different people talking about the sonic differences between op-amps... its hard to say if its all imaginary.
Note: I haven't tried it... and I suspect YMMV depending on starting amp. (OPAxxx) and then the upgrade you make. Burson, Sparkos, etc ...