Sony TA-E9000ES Amplifier "21v" Questions

...footswitch and boost channel). i think it may be Musician class, but am not sure--have it set to 21V, but really want to know what the factory sets it at, so as not to overdrive power amp. i had

...have lost most sound Hi, please have a look at your supply. The voltage might have gone below 21V on your newer models and 42V on your older models. This you will find near the pre-amp. Look