There is most likely nothing wrong with your Penta - note that its meters measure in dBFS. This is because there is an optional digital output and it is important to know the clipping point of the converter so as not to overload it and cause digital distortion. 0dBFS on the penta is equivalent to +22dBu (dBu is the common unit used to express signal level in the analogue domain). This is the absolute maximum level the input signal should reach and it is important not to have the O/L LED lighting. It is best to set the input level so that the green LEDs are lit but the yellow ones are not so that there is some headroom. This may require the input gain to be set to maximum but do not hesitate to do this since the Penta is designed to apply up to 60dB of gain to mic signals whilst retaining a flat frequency response.