The Serbian firm NAT Audio has unveiled the NAT Transmitter EVO tube monoblock amplifier, which the company claims is the finest model in the Transmitter series to date.
This amplifier’s output stage can function in two distinct modes: a high-power setting of up to 80 watts and a low-power setting of 40 watts. Both configurations utilize a directly heated triode in a single-ended setup, allowing the 80-watt mode to effectively drive a diverse array of speaker types.
The NAT Transmitter EVO monoblock is equipped with a Philips QB5/1750 output tube, which can handle a maximum dissipation of 565 watts. However, the amplifier operates at only 35% of this maximum, leading to a lower operating temperature that enhances reliability. The output tube’s design is notably robust, ensuring sound reproduction free from microphonic interference. Additionally, the amplifier’s housing, crafted from stainless steel, provides superior vibration isolation, thereby enhancing sound clarity. For compatibility with highly sensitive speakers, the Transmitter EVO includes a low output power option of up to 40 watts, which further minimizes power consumption and significantly reduces heat generation.
The input and driver tube (6N6P) utilized in the Transmitter EVO is new old stock (NOS), produced to military specifications. This amplifier features a wide-band output transformer specifically engineered for NAT. The output speaker terminals are crafted in a laboratory-style format. The tube monoblock NAT Transmitter EVO is designed to operate with speaker systems that have an impedance ranging from 2 to 16 ohms.
The power supply for the NAT Transmitter EVO amplifier is rated for a capacity that is double the power consumption of the device at its maximum output. Each stage of the amplifier, including the output stage, is equipped with individual voltage stabilizers. This power supply is constructed to ensure that sound quality remains unaffected by any potential voltage fluctuations in the electrical network. Additionally, a smooth start-up mechanism for the lamp filament power supply enhances the reliability of the NAT Transmitter EVO by preventing voltage spikes during the power-on process. The automatic bias current circuit eliminates the need for manual adjustment of the output tube current.
The NAT Transmitter EVO monoblock is constructed with top-tier components, including military-grade graphite resistors, Ohmite resistors, Vishay resistors with a tolerance of 0.1%, ultra-low ESR capacitors from Cornell-Dublier, electrolytic capacitors rated for 105°C, cutting-edge semiconductors, laboratory-grade connectors, and input wiring made of pure silver.
The standard model of the NAT Transmitter E VO power amplifier features an asymmetrical input via the RCA connector and includes a pseudo-balanced input on the XLR connector. The manufacturer provides two upgrade options for the amplifier: the initial upgrade involves the addition of a fully balanced input utilizing a hand-wound nanocrystalline transformer. The subsequent upgrade incorporates a transformer wound with copper-free silver wire for enhanced performance.
Specifications:
- Type: single-ended power amplifier, operating in class “A”
- Output power : max 80W @ 1kHz @ 4 Ohm or 8 Ohm
- Frequency response: 8Hz – 60kHz at 4 ohms or 8 ohms
- Input impedance: 100 kOhm
- Input Sensitivity: 1.0V RMS for 80W
- Gain: 28 dB (x25)
- Signal to noise ratio: 110 dB (A-weighted)
- Lamps: 1 x 6N6P, 1 x QB5/1750 (6079)
- Power consumption: 370 VA
- Dimensions of one monoblock (W x H x D): 360 x 310 x 640 mm
- Weight of one monoblock: 40 kg
