NAT

VACUUM TUBE POWER AMPLIFIERS

Microwave

Single Ended Mono Block Ceramic Tube Power Amplifier

Microwave is a new mono power amplifier made by NAT, based on military grade tubes in pure class A, single – ended mode with zero global feedback operation.

Main facts:

• First high power coaxial metal-ceramic tube zero-feedback single-ended power amplifier globally - unique device

• Most compact in the class (19"x19"x6.5")

• Most efficiency in the class (280W of power consumption for 80W of all tube single-ended class A)

Microwave gives an opportunity to listening the sound on two different mode as high power setting to 80W or moderate setting to 40W, both of pure coaxial-ceramic triode type. With power of 80W in single – ended configuration there is a capability to drive almost any type of  loudspeaker.

Military  grade(N.O.S - new old sock) GI-7B - output triode tube - represent high technology in vacuum tube manufacturing as coaxial metal-ceramic device. Potential of output tube reach 350W of heat dissipation. Microwave used 60% of max. dissipation that significantly decrease working temperature point for further reliability improvement. Construction of output tube GI-7B  is very robust also in mechanical domain – there is no microphonic effect for negative influence to the sound reproduction. Special designed coaxial metal-ceramic tube has much lower mechanical impact of reflected vibration from the environment then standard glass tube!

Input tubes ECC85 is also made by military standard (N.O.S.).

Driver tubes 6S31B-R (miniature type - two unit) is also made by military standard (N.O.S.). Tubes reach over 5.000h of operation! Tube 6S31B-R is also known as "SUPER" tiny tube!

Hand crafted wide-bandwidth output transformer (custom designed for NAT ) is used in Microwave. Output transformer is constructed with no less then 56 separated layers. Bandwidth reach 6Hz – 70.000Hz. as exceptional good flatness for single – ended zero feedback amplifier. Output taps for 4 and 8 ohms speaker load are realized with laboratory grade connectors

NOTE: Microwave may drive any load from 2 ohms to over 16 ohms. By specific technical approach output transformer in combination with output tube may drive easy any type of loudspeaker with damping factor equally as in push-pull configuration. Zero global feedback concept is the best solution for purity of sound reproduction without negative influence from wide variety of speaker impedance. Microwave may drive all type of speaker equally (electrostatic, magnetostatic, dynamic or other types).

Power supply section participate in sound quallity almost as amplifiers main circuit. Silent power transformer is designed for double the power then Microwave. There is a separate voltage regulators in zero feedback manner for all amplifier stages including the output one. Tonal quality is independent from line voltage fluctation. Equivalent available energy from power supply is huge, equal to no less then 8000 Joules (8kJ) of energy. Soft start additionaly improve Microwave reliability by avoiding high voltage stress during turn-on procedure. Polypropilene-in-oil type of capacitors is sed additionaly for the single output tube's high voltage supply.

Special high voltage (HV) air-core choke is used in Microwave as one of the best high frequency reduce element in power supply section!

No any adjustment of output tube's standing current is necessary. Automatic electronic circuit  adjust tube's current no matter of tube duration – means constant current in time domain –  from the brand new to the near end point of tube life.

Quality of electronic components that is used inside Microwave are at high level – polypropilene-in-oil capacitors, Caddock resistors, Vishay 0.1% resistors, electrolytic capacitors for 105C of operating temperature, last generation of  IXYS semiconductors, Schutzinger laboratory grade connectors, pure silver input wiring…

Microwave work properly at worldwide AC line voltage from 100 – 250 VAC, 50-60Hz (different voltages set in factory only).

NOTE:Last generation, high tech. FAN is used inside a chassis with noisless operation. 

NOTE: -Standard version use pseudo-balanced input
          -First step of upgrade : pure-balanced input realised with hand wound nano-crystalline core transformer
          -Premium step of upgrade : pure-balanced input realised with hand wound silver-ofc wired nano-crystalline core transformer