The E34L has a slightly higher grid voltage (-13.5 to -16.5 vs -10 to -13.5 volts for the EL34) than other EL34 / this tube offers tight low end with smooth mids.
Matched pair!
With a slightly higher grid voltage (-13.5 to -16.5 vs -10 to -13.5 volts for the EL34) than other EL34 / this tube offers tight low end with smooth mids.