so explain these readings from my A0200?
Left and Right channels with no "dummy loading" after a about a week of use.
The readings before sufficient burn-in time are on the bottom, left and right.
Exactly the same method of measuring as
@Toku. We share the same sort of electrical background though he actually studied for it and worked professionally as an EE for many, many years. I have about 30 years of Hi-Fi industry experience.
I'm not suggesting that your measurements or your methods are wrong. I am suggesting that there are many inconsistencies in technique. I hope you read the article that
@Toku kindly posted that should further your understanding.
The I think they are Vishay Caps are on both models, I'll post a picture for you so you can see them, they are located on a different area no doubt for packaging reasons.
There is no argument from me. I'm just suggesting that between Toku-San and I we have many, many decades of professional experience. Unless we have both been wrong for multiple decades. I will tell you that I am 44, have been in the industry since I was 15 with a work permit in California, and later, much much later, about 10 years ago I moved to Japan. Still in the Hi-Fi industry.
Picture of the aforementioned parts. Do you know what you highlighted btw?
And do you know what the parts that are on the A0200 but are not on the DA-9 are for?
There are a few major differences between the two amplifiers.
I can assure you that they are 99.5% the same sonically. I actually shipped mine back to Aoshida Hi-Fi Japan today to have a new model that actually reads Bluetooth and they will ship it back to me via FEDex.
Have you measured with the power and left over power within all the capacitors drained to see what parts you circled are? Do you know what they are, what they do, why they are there and why they are seemingly missing in the DA-9?
I will tell you that from my experience and during the short and I do mean short time I owned the DA-9, I found glaring flaws in execution. I left this board and moved over to the A0200 board because I sold my DA-9. I miss my A0200 right now but I have multiple tube amps, a few chip-amps, and another couple of Class-D amps.
The 0.04, 0.06 are taken after 10 minutes of idle time, and using sockets/banana's I've measured before and after the speaker cable, the measurements at the speaker are on average 0.02mV higher.
I'm actually sad that I sent my seemingly as close to perfect amplifier back to be replaced. I am fully expecting an amplifier that measures in the 0.3-0.4mV when I get a new one. Bare in mind that static measurements tell you if you have a MAJOR problem with your amplifier, anything over 60mV is not good, but brand new, it might be over 1mV at first, In a few hours or less it'll be nearly half unless there is a problem.
It's great that you are taking interest into how these amps operate but I would suggest highly that you learn about how amplifiers (esp Class-D) amplifiers are built. Why there are Zobel networks on speaker outputs on an amplifier for instance. And why speakers (most higher end speakers) have Zobel networks built in, so that's double Zobel-Networks! It's very interesting the theory becomes easier to understand as you learn more. In my case that meant I blew up, or smoked several amplifiers along the way from over-modding some amplifiers. I learned that if something sounds right from the factory that investigating and mucking around doesn't help, it usually does the other thing.
I hope you don't take this as a challenge, or as an insult. It isn't on both counts. I want people to understand circuits, how they work, why the parts are there. Why they were omitted in some cases. And why one op-amp might suit a specific purpose extremely well but that same op-amp might sound or work horribly in another circuit. These are interesting things to learn about. There's a reason why I have so ridiculously many op-amps left over and why I have favourites that I have multiple new units of that I have stored for a later day.
Towards the bottom I have added a slew of very similar shaped items, I know what each one does and can identify them, you can do the same if you can figure out what the numbers printed mean. I am only posting these pictures of SMD parts so you have an idea of what you circled are. And you have missed the single inductor that is on both the DA-9 and A0200 that is very obvious. I think you'll find it and it's nowhere near a 22mh inductor. Again I am not trying to be funny or whatever negative thoughts you might have. I am showing you how similar looking parts serve a very different purpose. And NO not all of these parts or similar ones are in either the DA-9 or the A0200. Some might be, but at different values and for a different purpose.
The only way I learned was from reading, and so on. I built my first amplifier from reading a book, memorising most of it, and built my first transistor amplifier from scratch at 10 years of age. It was much, much easier with transistors!
I do not know everything, I am constantly learning and being taught from my elders. Those who have been working with electronics for a VERY long time indeed.
One thing you learn after many many builds is that lets say two exactly the same value resistors fresh from the parts supplier measure within 0.01%. Then you apply voltage and it cycles power on/off a few times and that part that is a 0.5% part proves to be not only higher, but sometimes far lower even though you purchased them and cycled them exactly the same way and measured them in the same manner in within seconds of one another. This is a common occurrence and can be extremely frustrating when trying to make something that performs identically for 2 separate channels. I won't even get into gang error with volume pots. Some have insane error from left-right channel and are made and considered the "Velvet" standard. I actually don't use that brand because of their inconsistent performance. There are much better ways to have nearly error free 2 channel audio performance that is an analogue device. The question at that point is will it physically fit. Just like some of the discrete op-amps.
Since you show an obvious desire to learn, I encourage you to invest in books, measurement tools (try second hand oscilloscopes that have been refurbished PROPERLY. Once you have the tools, the better off you'll be and the more you will learn automatically. Your curious nature is something that needs to be nurtured. And don't be afraid to "Smoke" a few hopefully cheaper products. One great way of learning about Class D amplifiers is to modify one until you break it by exceeding it's limits. VERY easy to do. And always use better thermal paste than that white grease which is literally thrown in. Even your computer comes with that white grease unless you build your own. I use thermal paste rated at a minimum of 12.8. Usually I buy stuff that is 13.8 as it's good value. Standard white grease is somewhere in the low 2's. The higher the number, the more heat rejection/absorption potential it has.
Again, I'm not being critical. I'm glad you noticed the different layouts. There are several differences between the two. My A0200 just really opened up a few days ago, but I kept having the nagging feeling that if I don't take advantage of the fact that the latest A0200 without the typo would eventually bother me. So regardless of how well it measured, I decided to ask for the swap. Aoshida Hi-Fi Japan is extremely courteous and overly helpful. I asked them if I could wait a little while until I made up my mind. Their response was we'll exchange it whenever you'd like. They paid for shipping back to China and will pay for shipping from China to Japan for free. I can honestly say that I have not had such service from a Japanese company in years, probably decades.
Hope you figure out what those misc parts on the bottom are! They are all different. And there are a couple of red herrings in there!