The criteria for selecting input tubes also apply to power tubes:

super manufacturing technology and rigorous quality control. 
For example, tubes such as 6L6, made in USSR, have been Flagship tubes ever since the 50's. For over 60 years the manufacturing experience with these tubes has established the best possible reputation for the highest quality standard. 

Tube technology characteristics 
TOR-surface technology for the cathode emitter 
Special shape design and materials used for the tube plate (nickel carbonization) 
Specially designed filament heater structure 
Gold plated electron grids 
Punching technology for grids' manufacturing 
High resistance tube bulb glass

 

Power output tubes 
6P3C/ 6L6 
EL-34/6CA7 
6550/ KT-88 
G807 / 807 
6P1P/6V6 
6P42C/ EL 500 
Input tubes 
6H2P-EB 
6H1P-EB 
6H23P-EB 
6H9C 
6H7C

Electron Tubes 

AUDOLICI's products use mainly electron tubes made in USSR/Russia. There are two categories of electron tubes that are used: input tubes and power output tubes, both selected with individual strict criteria. 

The most important criteria is to make sure of the origin of the components. We only use tubes from suppliers that are top quality manufacturers, based on super tube technology, which means they assure the highest quality- Reflector/ Sovtek; Svetlana / SED; Kaluga. Every tube has passed rigorous quality control military standards. As a result of this rigorous selection, our products have minimum level of microphonic's effect, the best signal/noise ratio, the best reduction of external artifacts and environmental disturbances. The quality of the glass and of the vacuum allows each tube the maximum life time, which is a clear advantage over other intemational manufacturers.