I use an SIP-300 in my headphone system powering AKG K-1000s.
My amp is dead quiet. Digital bias is finicky. I'm not frying my 300Bs yet, so I think I'm correctly interpreting the bouncing readout. Very nice sound. Some folks on these forums rank PSET far below push-pull and SET in 300B sound quality preference. The only other 300B amp I've owned was a much pricier/trendier 300BXLS SET amp that was way too forward in its midrange presentation (so I sold it).
My amp is dead quiet. Digital bias is finicky. I'm not frying my 300Bs yet, so I think I'm correctly interpreting the bouncing readout. Very nice sound. Some folks on these forums rank PSET far below push-pull and SET in 300B sound quality preference. The only other 300B amp I've owned was a much pricier/trendier 300BXLS SET amp that was way too forward in its midrange presentation (so I sold it).