I got a bit more body in the sound when I replaced the stock power cord with a Delta Labs PC on my EAR 834P. You will realize a more dramatic improvement if you upgrade the tubes. I am using NOS Mazda 12AX7s. Other 12AX7s with good reputations are the GE 5751-WA Black Plate, the Sylvania black plate & Gold Brand black plate and and the Sylvania Gold Brand grey plate gold pin.