This regulator is a basic opamp shunt using a three terminal device as a constant current source, an opamp with a voltage reference for control and a power transistor as the sink device. Many hours of testing has gone into this regulator and I believe it’s one of the finest available for the price.
You can purchase the PDK Shunt Regulator as a bare board, a kit, or as an assembled unit. The same board is used for both the positive and negative regulators with jumpers determining which version the circuit will be.
The regulator can be modified to the users taste if desired by changing the opamp or changing the values of the input and/or output capacitors. The board is set up for 2 4700u input caps and either a 1000 u or 220u output cap. Other values can also be tried. Since bypassing of the supple lines on the circuit to be powered can interact with the out put capacitance of the regulator, and have a huge impact on the sound, we encourage the user to play with these values to obtain the sound desired.
For those who have not listened to a shunt regulator you will be surprised. A shunt just doesn’t get in the way of the music like a series regulator can. The simplicity of a shunt is also desirable. the performance versus parts count and cost is high.
The measured specification of this regulator are:
Output impedance: <10 milliohms @ 100KHz
<50 milliohms @ 1MHz
Noise: <3 microvolts
PSRR: 75 Db @ 20KHz
60 Db @ 100KHz
50 Db @ 500KHz
Prices:
Bare board: $20 US Each
Kit: $55 US Each
Assembled $75 US Each
