From the manual:
The Nº25 is available with "EITHER" a high-gain or low-gain phono option. Each option offers two internally adjustable gain settings via two twopole miniature rocker switches, one for each channel. The high-gain and low-gain phono options have been factory-adjusted at the lowest gain settings (58dB and 38dB, respectively).
You can’t change from low to high. It is an either low OR high, but not both. It would depend on which version was initially ordered.
The Nº25 is available with "EITHER" a high-gain or low-gain phono option. Each option offers two internally adjustable gain settings via two twopole miniature rocker switches, one for each channel. The high-gain and low-gain phono options have been factory-adjusted at the lowest gain settings (58dB and 38dB, respectively).
You can’t change from low to high. It is an either low OR high, but not both. It would depend on which version was initially ordered.