Review on KNACRO Voltage Regulator Three Terminal Rectifier by Francisco Taylor

I bought this to power an oscillator circuit that requires +15V and -15V rails. While +Vcc remained regulated at +15.1 VDC, negative (measured from ground output to -Vcc output) remained at around -9.48 VDC with a maximum input voltage of 34 VAC (datasheet says maximum AC input voltage is 36 VAC is, I left 2 volts). for the buffer). The LM7915's input pin seemed to match the output pin. No further diagnosis was made. I bought it to save time, not waste it. Poor quality control (but I wasn't expecting much at this price point).