PPA v2 Amplifier Board
PPAv2 is similar to PPAv1 except with a custom
discrete output stage, plus a few other enhancements.
The pre-made boards are no longer available, but the design files are
published below if you want to go and make your own.
- 6.3 in. × 3.925 in. board size (Eurocard size, 160mm
- Isolated power rails reduce rail-modulated
- Differential-drive topology gives the simplicities of virtual
ground without the crosstalk problems that normally go with that.
- The signal channels use the Jung multiloop topology for
- Compatible with most FET-input op-amps.
- Discrete diamond buffer output stage, with adjustable bias, to
let you trade portability for sound quality.
- Room for thousands of microfarads of
rail capacitance, even with low-density
audiophile caps. At the same time, differential drive means the
qualities of the rail capacitor bank don’t affect the sound of
the amp as much as in other topologies.
- Reverse power supply voltage protection.
- Quiescent power draw ranges from about 40mA on a minimal
feature set to about 120mA when maxed out.
- Enhanced JFET cascodes for
biasing the op-amps into
- Optional bass
- Board-mounted ALPS RK27 (a.k.a. "Blue Velvet") potentiometers
for volume control and bass boost adjustment.
- Resistors on 0.100" × 0.300" spacing allow the board
to be set up for easy
- A companion NiMH battery board
allows for portable amplifiers.
power LED turn-off circuit
for indicating that the batteries need to be recharged.
Where to Next?
View the PPA v2 Amplifier Schematic
View the PPA PCB Layout
Download the PPA ExpressPCB Design Files
Part Selection Guide
Step-by-Step Assembly Guide
Bass Boost Calculator
PPA v2 Benchmarks
Morsel’s PPA Site