NAT
VACUUM TUBE PHONO STAGE
Signature Phono
Battery Powered Vacuum Tube Phono Stage
NAT set a new standard in Phono state-of-the art product by new approach-vacuum based inverse RIAA network in model Signature Phono Vacuum RIAA. Standard inverse RIAA network based on resistor or even better inductor as main part in the signal path, but NAT put Vacuum field medium instead. Phono stage contains 8 vacuum tubes in full zero feedback configuration.
Battery supply is used for the military grade ultra low noise nuvistor 6S51N-B & 6S53N-B triodes with approximately 20 000h of life time all by military and N.O.S. type.
System of battery charging is full automatic.
AC voltage (for battery charging and logic) is filtered by separate encapsulated and shielded power line conditioner.
Low output types of MC cartridges are boosted by the premium with dual gain option amorphous 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 500 ohms Signature Phono may easy drive any interconnect cable at reasonable length.
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 Vacuum RIAA confirm original innovative approach of NAT globally.
Design Features
- vacum based inverse RIAA network-original approach by NAT
- absolute zero feedback (unique construction)
- pure class "A"
- triode based configuration
- battery powered supply
- 8 (eight) vacuum tube based phono stage
- military grade nuvistor triode (N.O.S.) vacuum tubes-up to 20.000h of lifetime
- premium amorphous input step-up transformers (with dual gain option)
- ultra low magnteic radiated toroidal power transformers for logic control
- full automatic battery charge
- soft start operate
- teflon insulated RCA input & output connectors
- gold plated sockets
- hand assembled all modulated chassis
- anodised 0.6"(15mm) thick aluminum front panel
- extensively used computer numeric control machines (CNC)
Specifications are subject of change without notice
| Technical Specification | |
| Name | Value |
| Frequency Response | 5 Hz to 100 kHz |
| Noise | < -90 dB "A" weighted |
| Gain | 38 dB MM + 20 dB MC HIGH + 6db MC LOW (TOTAL 64 dB) |
| RIAA Accuracy | ± 0.1 dB |
| Channel Unbalance | < 0.1 dB |
| THD & N | < 0.2 % |
| Input Impedance | up to 250 ohms for MC LOW, up to 1000 ohms for MC HIGH, up to 100 kohms for MM |
| Stereo Separation | > 96 dB @ 10 kHz |
| Tube Complement | 8 x nuvistor triode |
| Phase Status | (non inverted) 0 degree |
| Output Impedance | < 500 ohms @ 1kHz |
| Power Requirements | 100 VAC to 240 VAC @ 50 to 60 Hz, max. 90 VA |
| Dimensions | 19" (483 mm) wide x 22" (560 mm) deep x 5.7" (145 mm) high |
| NET Weight | approx. 60 lbs. (27 kg) unpacked + 16 lbs. (7 kg) = 75 lbs. (34 kg) (with power supply) |
| TOTAL Weight | approx. 113 lbs. (51 kg) packed in wooden box |