NAT Audio again introduced state-of-the art product, this time phono preamplifier-Signature Phono. Phono stage contains 6 vacuum tubes in full zero feedback configuration. Even local feedback is avoided.

Battery supply is used for the military grade ultra low noise 6N23P-EV triodes with approximately 10 000h of life time. These triodes are totally replaceable with any type of 6DJ8, E88CC but are very best among them.

System of battery charging is full automatic.

AC voltage (for filament, battery charging and logic) is filtered by input encapsulated and shielded RFI power line filter.

Low output types of MC cartridges are boosted by the premium Jensen step-up transformer.

Passive RIAA equalization is applied regarding the philosophy of zero feedback concept. Signal-to-noise ratio is impressive (over 90dB), partly thanks to battery supply.

With output impedance of around 900 ohms Signature Phono may easy drive any interconnect cable at reasonable length. Input resistance and capacitance may be adjusted in many steps by DIP switches on rear preamplifier's panel to match cartridge impedance.

High quality gold plated teflon isolated connectors, both input and output are used in phono stage.

Each Signature Phono preamplifier is hand crafted device with burn in test period of 100 hours.

Again, Signature Phono confirm original innovative approach of NAT globally.

	Test of Signature Phono - phono stage in Stereophile from July 2007 published by Michael Fremer (pages 28, 29 & 30).
	- RECOMMENDED COMPONENT class "A" (page 68)

Frequency Response

5 Hz to 100 kHz

Noise

< -90 dB "A" weighted

Gain

40 dB MM & MC HIGH + 20 dB MC LOW (TOTAL 60 dB)

RIAA Accuracy

± 0.2 dB; +0dB/-0.4dB

Channel Unbalance

< 0.05 dB

THD & N

< 0.1 %

Input Impedance

up to 40 ohms for MC LOW & variable from 10 ohms to 47 kohms for MM & MC HIGH

Stereo Separation

> 96 dB @ 10 kHz

Tube Complement

6 x 6N23P-EV military grade (identical to any  E88CC)

Phase Status

(non inverted) 0 degree

NET Weight

approx. 60 lbs. (27 kg) unpacked

TOTAL Weight

approx. 95 lbs. (43 kg) packed in wooden box