Last year and this spring I spent a lot of free-time on DIY electronics and as my full-time job is also electronics related, I needed to take a few-month break. I just didn’t feel interested, inspired, or motivated anymore. During the time off I focused a bit more on my photography hobby. I hoped that after a break I would feel motivated to do more electronics again. While even I had my doubts, the inspiration is back! I am designing new boards again. There will be a new DAC plus addon boards; the design and ideas are based on the H-DAC. I will also try to make assembled boards available to buy at some point.
I am currently designing a new DAC that I could also start selling as assembled boards. I will open the selling plans below a bit more.
In the new design I am using the experience and ideas from H-DAC and other boards I have done so far. The design will share similar ideas but hopefully slightly simpler implementation. I am also thinking of releasing two or three different versions with changes in price and performance level.
The base board will likely have coaxial and optical digital inputs and an external I2S input for 3rd party USB to I2S modules. Like H-DAC did – except I will get rid of that lousy combo-connector. As I like modular designs, it will support stackable addon boards such as Addon BalOut and extra digital inputs.
At first I was thinking of designing the DAC around TI PCM1789 as the implementation would be quite a lot cheaper than PCM1794A-based circuit with I/Vs and such. However, the board will be quite complicated (which unfortunately means not super cheap) anyway, mostly due to the S/PDIF receiver circuit. Therefore, I may go back to PCM1794A as the ultimate solution and maybe offer a cheaper version with pin-compatible PCM1798 and cheaper opamps. We’ll see.
Speaking of S/PDIF receiver, I have spent hours today trying to figure out if AK4118A would be a good replacement for CS8416 which is expensive and has a wacky feature of holding the last sample in unlock when used in hardware-mode. I will probably write another post regarding that.
Selling assembled boards
For some time already I have wanted to sell my boards to fellow DIYers. While bare PCBs are available for sale, those are for a very limited audience as you need quite good electronics skills and confidence to assemble and test the boards. Many makers who have the skills already design their own boards. Obvious next step is to offer fully or partly assembled boards.
First of all, I have not designed boards for manufacturing yet. Therefore, this will require a bit of time to learn and think through but thanks to companies like Elecrow, where I already get my PCBs done, also offer affordable manufacturing and help to go through it. Manufacturing also requires a small investment even if starting with care as the smallest reasonable batch to manufacture is probably in the order of 50 or so. Given many audio components are quite expensive, sourcing components and manufacturing boards cost some money – especially considering all the addon boards as well. But no, I am not going to do a Kickstarter campaign (yet). I will take the (still small) risk if things look promising.
When I get the design tested, measured and finalised, my plan is to first hand-build some boards and put these on sale. I am thinking of opening a Tindie store also when I get few different products to sell. If/when these sell and I get some feedback, I could take the leap to produce a small batch of assembled boards.
As this is a hobby I cannot and do not want to commit on any dates. If the inspiration remains high I am positive to get the design ready soon as it is largely re-using older designs and ideas. Then it is ordering the PCBs, building, testing, measuring, debugging, changing the design and possibly re-spinning the PCBs and so on. When it’s ready I will hand-build a couple of boards and try to sell them. If the feedback is good, or at least not bad, I will see about going forward with a small assembled batch.
My personal target is to get it done still in 2018. But as always, this may slip.
PS. As seen on the cover pic, I have bought some larger-than-normal amount of components, this is already a commitment to myself to get something done!