Willsenton R8 KT88/EL34 x4 Tube Amplifier Integrated AMP Power Amplifier Headphone Replaceable Basic Meter (Silver)

One amplifier can used wiht tube EL34, KT88 or 6550, so, you can get 3 kinds of sound from different models tubes. The default matching tubes of this machine is KT88. If you need another 2 new sets of tube, please purchase in addition. There is a Red selection button on the Back of the amp to switch.