The Mahi Amplifier Features And Specifications: Input Tube: 1 x 12AT7WA Ei large plate Driver Tube: 1 x 6414 JAN NOS GE or Raytheon branded Output Tubes: 4 x EL84M - 6Pi14Pi-EB NOS Russia Output Tube Quiescent Standing Current: 20mA Set Bias for 200mVDC measured across each 10 ohm cathode resistor Gain: 29dB Negative Feedback: MIN= 3dB; STD=6dB; MAX=10dB of global NFB Input Impedance: 110 Kohm Input Sensitivity for Maximum Output Power: defined as input voltage required in order to produce maximum power output reaching 1.5% THD @ 1KHz Maximum Output Power: defined as power output reaching 1.5% THD @ 1KHz Signal to Noise Ratio Ref. 1W: Typically 82 dB A-WGT 20-20K Noise Floor: Typically 150µV = -74dBu A-WGT Noise Floor: Typically 650µV = -62dBu unweighted Dynamic Range: 83dB THD+Noise @ 5W: less than 0.15% Frequency Response at full power UL mode w/MAX NFB: 20 Hz to 20 kHz FLAT Frequency Response at 5W into 5 ohms: 10 Hz to 30 kHz FLAT, -3.75dB @ 100KHz Recommended Speaker Load: Optimized for 5 ohms Dimensions: 11" deep x 10" wide x 5" tall Shipping weight each: 18 pounds Read the Owner's Manual