Another batch of boards

Another small batch of prototype boards for projects has arrived. I’ll test these as soon as I find the time to stuff and test the last batch of experiments…

dc heaters
Simple 6.3V to 12V regulated heater board (LM7812 based), good for phono builds
mini booster
A miniature DC booster board with on-board USB charger for battery power B+
opamp phono
A simple opamp phono preamp powered by a couple of 9V batteries just because