I have the SMSL DA-9 and I'm a complete nerd, so I did some measurement comparisons with Fosi Audio V3.
Setup:
- Speakers right next to each other
- UMIK-1 positioned one inch out from each speaker
- Microphone was positioned between the woofer and tweeter of my ELAC Carina's (strongly recommended!)
- Level matched using REW "Check Levels" feature. About 90% on the Fosi dial and 52 on the DA-9.
- Did the listening tests
- REW ran on each speaker
This is the full picture (20/20k) with 1/48 smoothing. The DA-9 is in green and the Fosi Audio v3:
View attachment 295540
Notice how jagged the SMSL is compared to the Fosi and look at the high frequency boost starting around 16k. We're looking at 6 DB difference from peak to trough. To me, this is an indication of the differences of the TPA 3255 vs the Merus chip in the DA-9.
Zooming in a bit without smoothing applied. This is between 14k and 18k:
View attachment 295542
This really shows the differences in the chips and therefore the amps. The SMSL has wild swings while the Fosi is just drifting down.
Zooming into 20-1k they are basically the same:
View attachment 295544
I would call this run to run variation because they are very close.
Lastly, 1k-5k with 1/48 smoothing applied:
View attachment 295545
They are basically the same but the Fosi seems more well-behaved.
Listening Tests:
I did the listening before the measuring, so I wasn't biased in any way. They were extraordinarily similar but the SMSL was a bit more airy at the top end. To me, it sounded artificial after hearing the Fosi right before or after. It wasn't bad, offensive, or a deal breaker in any way, but there was a minor difference. Ha, I was glad to see the measurements reported the same. I still hear pretty well up to 15k. Bottom line: they are both great units but I think we see the real-world implications of the old Merus chip in the DA-9 vs a top-notch implementation of the TPA 3255 in the measurements and listening tests.