June 13, 2020

I had been using ITEAD studio for PCB’s and I still like that service, but it seemed like the prices were higher last time I got boards, so I decided to go with SEEED Fusion. Wow–these guys are good. I got 10 boards for that ESP-DSP design for $4.90 and splurged for DHL shipping at $20. I put in the order on June 4 and got the boards on June 12. Just a couple of days for production, and then a few more days for reasonably priced shipping from China. This is great service given the price!

That $4.90 price for 10 boards is only for certain sizes and “normal” quality, but it worked out fine for this design. The boards look nice–I’ll see if I can do some debugging in the next week. I’m still amazed at the price. I also re-did the 4-channel amplifier module described in the Fully Modular design since there were some “issues” that I wanted fixed. That board was much more expensive, since it is a 4-layer board with ENIG coating , so a run of 10 was about $60. Maybe if that design works out OK I’ll redesign it for 2 layers and see if I can get the price down to $4.90. But $60 for 4-layer boards with ENIG is still very good.

BTW, the ESP-DSP design is a cell-phone-programmable 2-way stereo or 3-way mono board with up to 8-pole crossovers, 12 bands of EQ, BSC, delay, volume trims and bass enhancement (ADI’s SuperBass). It’s just 2 major modules plus some power supply components, with no SMD parts. It’s easy to build and it’s inexpensive. It should be a nice board with a lot of applications.

But more importantly, the ESP-DSP board is where I’ll try to “finalize” the Arduino code and replace the many files of code with library calls. After working on this code for so many years I finally have a good feel for how to partition it for efficient code reuse. Usually summer isn’t “software season” for me, but everything seems upside-down anymore with this pandemic, so who knows…