Checking in to update. The DA-9 I have now is very dependant on the DAC paired with it. Bought the Sanskrit 10th MKII, SU-9 and SU-9N. Also dragged my nuts across the glass pieces of the internet to acquire the AO200. Speakers used for comparison are the Wharfedale Diamond 12.2 and Polk R200, 2 very neutral speakers bar the intentional BBC Dip on the 12.2. One would think the SU-9 would decimate the Sanskrit 10th MKII in every situation but that seems to be the total opposite in my case with such speakers. The SU-9N and especially SU-9 sounded darn dry with such combos, making it sound sterile. The Sanskrit injected the much needed warmth into the mids, making it absolutely glorious. Price does not matter one bit, matching does. And I liked the DA-9 more than the AO200, the AO200 has a more forward sound, losing depth and realistic instrument separation. I have always aimed for vocals coming a step behind the speakers rather than from inline with the speakers, the DA-9 gives me that. Low frequency is a little warmer on the AO200, the DA-9 has leaner bass but quicker and more precise. The AO200 does not sound the same as the DA-9, regardless what people claim. For folks with very neutral speakers, the DA9 and Sanskrit MKII will most probably be the best combo, the SU9-DA9/AO200 combo just sounds too sterile. If you have warm sounding speakers, the SU9 will neutralize a bit if thats what you wanted.
I too owned the DA-9 but replaced it with the AO200 for one major reason, I wanted the display to "auto-off" because it is my preferance.
The amplifiers definitely do sound different. There are a few visible component differences as well as the length of the trace for the circuitry for the op-amps. Like you said, you like the sound of the DA-9 with your Wharfedale speakers and with your chosen DAC. It could be that component matching is somehow better, or your ears simply prefer the sound. The AO200 does sound different. With my equipment, it's less forward than the DA-9, It's got a little bit more of a lower midbass bump (very slight), the extreme upper registers are with my speakers clearer and better staged. I use the RME ADI-2 DAC fs, mostly it's set to flat other than at night to cut the bass for the sake of the neighbours.
I think that both amplifiers definitely have small differences and that dac performance and matching for sonic character is more important than spec sheets. Both amplifiers sound extremely good. The differences are not huge and I think that the chosen source material, method of transfer of the audio file itself has more to do with the sound than the amplifiers themselves. It's amazing that 15-20 years ago you would pay $1500-$2000 for similar sonic fidelity, and possibly not reach the level of sound quality that these new Chinese Class-D amplifiers can provide and offer. I think the future is very bright for hi-fi from these less established companies as long as they get the quality control under control.
I love my AO200, it simply works and does exactly what i want. I wish it had literally double the output power and double the power-supply if not more than double the current supply from the PSU. I'm sure that's coming in a year or two. A 4-500 watt Infineon/Merus Amplifier in a case that isn't much larger than the AO200 would be fantastic and looking at the actual amplifiers internals, it's definitely possible. They would have to make a PCB that is multi-level, rather than a single sheet to make the room. I would happily pay $500-$600 for such an amplifier. With all of the sound quality that the AO200 and DA-9 offer. If both the DA-9 and AO200 had double the power output, I think all of the small (not really complaints, but wants/desires for more) would be resolved and then some. Class-D is an odd thing. A tube amplifier operates by converting massive amounts of current through huge output transformers. Class-D doesn't do this. Tube amplifiers draw 100% of it's current the instant it's powered up, the volume knob is just an attenuator. Class-D is power on demand. It's PWM, it's good, it's a good compromise, but it's a compromise. With a tube amplifier, a 40watt tube amplifier will sound incredibly powerful and loud for mostly all consumers. If you have very large and expensive speakers (speakers that easily cost as much as a compact car, new), then you'll want a much more powerful tube amplifier which they do make. Hopefully your house's electrical system is up to par to supply all that current that is demanded. There's a lot of ways to make high performing, high fidelity amplifiers.
We are now at a level in consumer grade audio that is only possible because of Class-D and also cheap labour and also property values in certain countries. It's high time that the old guard of established brands take note of the newer upstarts and pay attention. They are beating the old guard at their own game. Many people ask me what amplifier, what speaker they should get next. I never hesitate to recommend SMSL amplifiers. I also don't hesitate to suggest $25 TPA3116D2 amplifiers. Some of them sound incredibly good especially when you pair them with a 24v 10amp power supply. Of course the SMSL offerings are better, but on budget, or for something in your garage? A cheap TPA3116D2 will more than suffice. The audio world has changed, the consumers are very aware of this, it seems the old guard is still hanging on to yesteryear.
The Topping PA5 is it? That amplifier has my attention. I know of several people who have them on order and are awaiting delivery so they can take it apart! I really want to know how they made it. Topping hasn't made a power amplifier for a while, not one worth really mentioning. This new one seems to be a game changer on specs alone.
I'm also a fan of transistor amplifiers and tube amplifiers and have several of each, including many class-D amplifiers. Each one has it's benefits and negatives. We're spoiled for choice. It's a great time to be an audio-nut!
I agree with your comments about the sonic differences. They exist. It is definitely speaker dependent and DAC dependent though. Some speakers like my own custom built speakers (designed by me) sounded far better with the AO200 over the DA-9 in every regard. The DA-9 was comparatively overly forward sounding and a bit on the "bright" side. However the AO200 is also very sensitive to impedance loading. I think it's the internal zobel circuit that makes this more or less apparent. The best results I've had so far with the AO200 for sound reproduction with everything being the same is with a 4ohm speaker with medium sensitivity, something in the mid 80db/watt region. 6ohm speakers sound ok, but there's something strange that happens with a 6ohm nominal speaker, I think it's a phase issue, maybe the crossover network inside the speaker. 8ohm speakers play fine regardless of the complexity of the crossover. I paired the AO200 and DA-9 to a 3 way speaker that has a 24db/octave crossover for all drivers and the amplifier was unphased by the loading. In fact it sounded as good as when playing a 4ohm load. 6 ohm loading could be something to do with the crossover. My guess is that the tweeter is crossed over at 6db/octave and the woofer at 12db/octave. That would create a phase issue if not dealt with properly.
Regardless the amplifiers are both extremely capable and reproduce and do exactly what they are supposed to do, amplify the input signal as cleanly as possible and make things louder. Of course that means any short comings will also become more apparent. Component matching becomes important be it a DAC or other intermediary pre-amplifier, they all have different input/output impedance and capacitance. Amplifiers are sensitive to these things. Sometimes you find a magical combination that really works fantastically well, other times, it's less than optimal.
I'm glad that your findings are very much in line with my own. Slightly different, but that's down to equipment and listening habits I'm sure. Both amps are very capable. I don't think there's much need for a debate on which is better, I think it's purely preference when amplifiers perform at such a high level, and lets not forget the incredible bargain basement pricing.
@MarkWinston I agree with you and your assessment. Objective and also adding just enough subjective opinion to help those who haven't made the purchase decision. I think personally at some point, the physical appearance also takes a role. I like that the display can be shut off by timer, for me, this is a must have. I don't think there's a wrong choice between the two. There will always be the latest and greatest Class-D amplifier, it's the natural progression of things. Sometimes a certain company will make a product that is incredibly overpriced for their customer base, and they simply do not sell, nor do they have many reviews or discussions on many audio forums. Companies should listen to their customers, provide what they want and improve on what they have successfully created. Making 10 new amplifiers in a production year only serves to confuse the customer. I'm not mentioning the brand on purpose, but I'm sure you know full well who I'm speaking of.
I hope you continue to enjoy your amplifier(s). The AO200 took about 2 weeks for me to fully "burn-in". I noticed small changes for a week. Each time I would unplug the amplifier from the mains and let it sit for an hour before plugging the amp back in. I'd leave the volume to the same level, and use the same music to hear any improvements. I noticed the same process with the DA-9. Maybe more pronounced with the DA-9 but mine was an early production DA-9. So who knows!
Above all else, it's up to you to decide if you like what you hear. It's not my amplifier in your home/room, or your speakers or DAC. If you like it, that should be more than enough unless you want to brag to your friends about your new fangled awesome amplifier! lol.
Take care!