u/Soulreaper71

I’m designing a multi-channel USB audio interface PCB as a learning project and I’d like some feedback before I start routing.
Current plan:
STM32F407
USB3300 (USB High-Speed ULPI PHY)
TDM/I²S audio
Initially 8 channels
Future expansion to 32 channels
Up to four PCM1681 DACs (I’ll probably only populate one for the first prototype)
I’m mainly looking for feedback on the architecture.
Am I missing any important components?
Is the STM32F407 + USB3300 + PCM1681 combination a reasonable approach?
Are there any common mistakes I should avoid before designing the PCB?
If you’ve built a similar project, I’d appreciate any advice.
I’m doing this mainly to learn, so any pointers are welcome.

I’m designing a multi-channel USB audio interface PCB as a learning project and I’d like some feedback before I start routing.
Current plan:
STM32F407
USB3300 (USB High-Speed ULPI PHY)
TDM/I²S audio
Initially 8 channels
Future expansion to 32 channels
Up to four PCM1681 DACs (I’ll probably only populate one for the first prototype)
I’m mainly looking for feedback on the architecture.
Am I missing any important components?
Is the STM32F407 + USB3300 + PCM1681 combination a reasonable approach?
Are there any common mistakes I should avoid before designing the PCB?
If you’ve built a similar project, I’d appreciate any advice.
I’m doing this mainly to learn, so any pointers are welcome.

I’m planning a DIY USB audio interface and would like some advice from people with experience designing USB audio hardware.
My goal is:
Version 1: 8 analog output channels.
Future version: around 13 analog output channels.
Architecture:
PC → USB Audio Controller → DAC(s) → Amplifier(s) → Speakers.
I don’t want to use XMOS if possible because of cost and availability in my country.
I’m wondering:
Is an MCU such as an STM32 or Raspberry Pi Pico 2 realistic for implementing a USB Audio Class device with 8 output channels?
Is USB Full Speed enough for 8 channels at 24-bit/48 kHz, or is USB High Speed practically required?
Would you recommend using multiple synchronized stereo DACs with shared clocks (BCLK/LRCLK/MCLK), or a single multi-channel DAC?
Which USB audio controller ICs or MCUs would you recommend for a DIY project like this?
If you were designing this today, what architecture would you choose?
I’m not looking for the easiest solution—I want to understand the architecture and build it myself as a learning project.
Any advice, references, or open-source projects would be appreciated.
( personally I want a very cheap option that why I skipped xmos mostly on availability and prices you know supply and demand stm32h7 series was same exepnsive as the xmos so got a very cheap option )