Inovative Audio Manufacture

Single Ended Mono Block Power Amplifier

Magma M is reference point power amplifier made by NAT as pure class A, single - ended type with zero global feedback configuration.

Magma M gives an opportunity to amplify the sound by two different mode as high power setting to 130W or moderate setting to 50W, both of pure direct heated triode (DHT) type. High power in single-ended configuration give a capability to drive almost any type of loudspeaker.

Direct heated triode (D.H.T.) type 6C21 (or equivalent) as output device represent high technology in vacuum tube manufacturing. Potential of output tube for audio purposes reach 450W of heat dissipation! Magma M used operating point that significantly decrease working temperature for further reliability improvement. Construction of output tube is robust in mechanical domain, resulted in non - microphonic sound reproduction. Special designed aluminium pipe 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 offer low mode option to lower the output power from 130W to 50W. Further, it decreased power consumption of output tube that resulting to additional lower heat dissipation.

Input and driver double triode tube ECC85 is chosen as N.O.S. (new old stock) grade of the highest guality. Hand coiled wide-bandwidth output transformer (custom designed for NAT) is used in Magma M. Output transformer (hand coiled as well) is constructed with no less than 40 separated different layers. Bandwidth reach 9Hz - 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: Magma M may drive any load from 1.5 ohms to over 32 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's impedance. Magma M may drive all type (electro-static, magneto-static, dynamic or other types) of speaker equally.

Power supply section participate in sound quallity as well as amplifier's maincircuit. Silent power transformer is designed for triple the power then Magma M consume.  There is a separate voltage regulators in zero feedback manner for all 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 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 are at high level: aerospace grade foil resistors, military grade power RF resistors, Vishay 0.1% resistors, electrolytic capacitors for 105C, last generation of IXYS semiconductors, Schutzinger laboratory grade connectors, gold plated all tube sockets, pure silver input wiring ...

Magma M 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 realised with hand coiled nano-crystalline core transformer
          -Premium step of upgrade : pure-balanced input realised with hand cioled silver-ofc wired nano-crystalline core transformer



Technical Specification
Name Value
Type Single Ended Class "A" Triode (D.H.T.)
Power Output max. 130 Watts @ 1 kHz
Frequency Response 9 Hz to 70 kHz -3dB
Input impedance 100 k ohms parallel with 200pF
Input Sensitivity 1.8 V RMS for 130Watts
Gain 25 dB (x18)
Noise 110 dB below rated output "A" weighted
Phase status Regular ( 0 )
Tube Complement 1x ECC85 & 1 x 6C21 (or equivalent)
Power Requirement 110 to 240 VAC @ 50 to 60 Hz, 550 VA max. (set in factory)
Dimensions 11.8" (300 mm) wide ´ 20.9" (530 mm) deep ´ 10.2" (260 mm) high
NET Weight approx. 133 lbs (60 kg) unpacked / per block
TOTAL Weight approx. 327 lbs ( 148 kg) packed in "flight case" crate / per pair

Design Features

- single-ended pure class A mono block power amplifier
- zero global feedback
- triode based configuration
- short signal path
- no inter-stage transformer on signal path
- no coupling capacitor on signal path
- output section - direct heated triode 6C21 (or equivalent) (N.O.S.) output tube
- driver section - double triode ECC85 tube (N.O.S.)
- hand coiled output transformer (custom designed for NAT)
- silent operation hand coiled power transformer (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
- hand assembled all modulated chassis
- high mass Schutzinger 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
- aluminium pipe type cover cage (laminate type optional)

Specifications are subject of change without notice