Magma M Evo is reference point power amplifier made by NAT as pure class A, DHT (direct heated triode) single - ended type with zero global feedback configuration.

Magma M Evo gives an opportunity to amplify the sound with two different mode as high power - setting to 100W or moderate - setting to 50W, both of pure direct heated triode (DHT) type. High power output in single-ended configuration give a capability to drive almost any type of loudspeaker.

Direct heated triode type 6C21 (or equivalent) as output device represent high vacuum technology in vacuum tube manufacturing. Potential of output tube for audio purposes reach 300W of heat dissipation! Magma M Evo used operating point that significantly decrease working temperature for further reliability improvement. Construction of output tube is robust in mechanical domain as well, resulted in non - microphonic sound reproduction. Special designed aluminium cover cage additionally improved feedback vibration effect from the environment, correlate with increasing of micro detail in sound reproduction. For the sensitive loudspeaker Magma M Evo offer low mode option to lower the output power from 100W to 50W. Further, it decreased power consumption of output tube that resulting to additional lower heat dissipation.

Input highest gain double triode tube 12BZ7 is chosen as N.O.S. (new old stock) grade of the highest US made guality. Wide-bandwidth output transformer (custom designed for NAT and custom produced for NAT) is used in Magma M Evo. Bandwidth reach 8Hz - 80.000Hz 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.

For the first time NAT introduced in Magma M Evo - Linear Field output transformer!

What does it mean? It means that the frequency response in Magma M Evo is totally independent from different output tap! For example if 8 ohms speaker put on 4 ohm tap then frequency response will stay the same (no any drop)! There is no "window" for escaping of HF (high frequency) from 4 ohms or 8 ohms tap on connected speaker (read more in Manual)!

It makes Magma M Evo very universal unit as there is an option for power/damping factor combination! Please read more about this in Manual as well!

For the first time NAT introduced in Magma M Evo - bass boost , as addition function! It helps for bass extension as add approx. 3 dB ref. to mid. range! Act as linearization for the bass response on loudspeaker behaviour! That's helpful also at low level listening , boosting the bass responce to higher level!

NOTE: Magma M Evo may drive any load from 1 ohms to over 32 ohms. By specific technical approach, output transformer in combination with output tube may drive easy any type of loudspeaker with higher damping factor. Zero global feedback concept is the best solution for purity of sound reproduction - without any negative back influence from loudspeaker.

Power supply section participate in sound quallity as well as amplifier's main circuit. Silent power suppliers unit is designed for double the power then Magma M Evo consume.  There is a separate voltage regulator in zero feedback manner for amplifier's driver stages. Equivalent available energy from power supply is equal to no less than 500 Joules of energy. Soft start additionally improve Magma M Evo reliability by avoiding high voltage stress during turn-on procedure.

No any adjustment of output tubes standing current is necessary. Electronic circuit automatically adjust current through mighty 6C21 (or equivalent) tube 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 Magma M Evo are at high level: film and foil in oil capacitor, aerospace grade foil resistors, military grade power RF resistors, Vishay 0.1% resistors, electrolytic capacitors for 105C, last generation of SIC cascode J-FET semiconductors, laboratory grade connectors, anti-vibration supported all tube sockets mechanics, pure silver-ofc input wiring ...

Magma M Evo works properly at world wide AC line voltage from 100 - 250 VAC, 50-60Hz (different voltages set in factory only).

NOTE:

-Standard version use pseudo-balanced input (pin-3 connected to pin-1)
-First step of upgrade : pure-balanced input realized with copper wired hand coiled nano-crystalline core transformer
-Premium step of upgrade : pure-balanced input realized with hand cioled silver-ofc wired nano-crystalline core transformer

 NOTE: Protect covers should always be placed over output (big) tubes due to safety!

Design Features

• single-ended pure class A mono block power amplifier
• zero global feedback
• triode based configuration
• shortest possible signal path
• no inter-stage transformer on signal path
• no coupling capacitor on signal path (only output transformer stage)
• output section - direct heated triode 6C21 (or equivalent) (N.O.S.) output tube
• driver section - double highest gain triode 12BZ7 tube (N.O.S.)
• custom produced output transformer (custom designed of NAT, custom produced for NAT)
• silent operation 6 hand separate power units (custom designed for NAT)
• special power supply coiled choke (custom designed for NAT)
• additional polypropylene capacitors in power supply for the output tube
• regulated power supply for filament of the output tube
• regulated power supply for filament of the driver tube
• double regulated HV power supply for driver stages
• over 500J of energy storage for main HV power supply
• automatic bias current control for the output tube with long term stability
• soft start operate to improve reliability
• CE comfortable ref. to use max. level of high voltage for domestic - (NAT do not use voltages that are above CE mark)
• hand assembled all modulated chassis
• high mass laboratory grade output connectors
• gold plated PTFE insulated RCA input connector custom ordered from NAT
• extensively used computer numeric control mashines (CNC)
• 4/5" (20mm) thick front panel
• protect cover cage

Specifications are subject of change without notice

Technical Specification

Name Value

Type Single Ended Class "A" Triode (D.H.T.)

Power Output max. 100 Watts @ 1 kHz

Frequency Response 8 Hz to 80 kHz

Input impedance 100 k ohms parallel with 200pF

Input Sensitivity 1.4 V RMS for 100Watts

Gain 26 dB (x20)

Noise 110 dB below rated output -"A" weighted

Tube Complement 1x 12BZ7 & 1 x 6C21 (or equivalent)

Power Requirement 100 to 240 VAC @ 50 to 60 Hz, 350 VA max. (set in factory)

Dimensions 13.8" (350 mm) wide ´ 20.5" (520 mm) deep ´ 13.8" (350 mm) high

NET Weight approx. 100 lbs (45 kg) unpacked / per block

TOTAL Weight approx. 264 lbs ( 120 kg) packed in "flight case" crate / per pair