After 50 hours the tone and dynamics "wake up." A magnificent tube particularly when used with the Linlai E300B. Tone is simply exquisite. Dynamics can be shocking. Delineation of instrumental voices is outstanding. Shipping may cause failure but Linlai appears to stand behind their products with immediate replacement. The folks are Hi-Fi Amplifiers take care of their customers when failures arise. Excellent communication and prompt shipping. A great outfit. A+