Hi,
For DAC board testing purposes we prototyped a plug&play GPIO based regulator board which goes between a raspberry pi and any DAC board.
Based on our aim for designated regulators the board provides thru the GPIO pins
– single regulated 5V to the raspberry
– single regulated 3V3 and
– tracking preregulated 5V to the DAC board.
At least for HifiBerry & IQaudIO we see that their boards use GPIOs 3V3 for digital and 5V for analog sections. The 5V for the analog section of the DAC chip play a major role in the overall sound quality which is why we used a fairly good linear regulator design using LT1086CTs here.
A typical stripboard is cut to HAT specs. The DD PARC regulators ar attached below (heat dissipation thru the board to heat sink), other parts fitted as usual. The male GPIO is mounted thru the board while a female header with spaced out pins is mounted on the strip side. The DC pins are split (allowing to feed designated power) and all other pins are connected.
The boards needs at least 10V DC which we provide with a large toroidal transformer + 2 large caps in a CRC configuration.
Material costs are pretty low for the outcome. Building them was little bit challenging though. They poof to be easy in use – we are periodically listening to what’s new on the market and won’t do that with only power to the pi (that’s horrible). On the other hand it’s not feasible to build more sophisticated power supplies around each board we are interested in.
