The LM-150IA uses for its power stage 4x KT150 polarized class AB and delivering a power of 2x100W RMS. Tubes we choose are Shuguang 12AX7, Shuguang 12AU7, Electro Harmonix 6SN7 and Tung-sol KT150. No matter it is the Pre-stage or power stage of tubes we select and choose the best matching ones to use same unit of amplifier to get the best sound quality out of it. Different from other inputs Pre-In offers you a possibility to connect to some other Preamplifier so that you can the LM-150IA as a power amplifier. User bias control has been used for bias adjustement including 2 vu-meters.