You don’t , and what brand is it and price , when buying a preamp Never
buy one with a $20 Alps blue velvet look in your preamp ,
prima luna a perfect example $5k and you see a round Silver round can
which is just 2 plastic wipers with a contact spray on the plastic
youwant a resistive ladder, or relay which is night and day better l
Linear Tube Audio makes a excellent preamp that is built far better then most for under $6k.