NAT Audio Magnetostat Reference Absolute Zero Feedback Vacuum Tube Line Stage

Magnetostat is a new reference point line stage made by NAT standards – transformer coupled pure triode class A with absolute zero feedback circuit configuration. Military grade type 6S31B-R output tube is used – represent high technology in vacuum tube manufacturing.
All tubes are also by N.O.S. (new old stock) and military grade and have high reliability. Construction of output tube 6S31B-R is very robust also in mechanical domain – means there is no high level of micro phonic effect for negative influence to the sound reproduction. Hand crafted wide-bandwidth output transformer (custom designed for NAT ) is used in this unit. Output transformer contain no less then 78 layers. Open bandwidth is from 3Hz – 400.000Hz. That is extremely good result for high direct current single ended transformer coupled operation mode. Output has separate configuration for single ended and balanced operation!

By specific technical approach mention output transformer in combination with single output tube may drive easy any type of moderate lenght interconnect cable.

Absolute zero feedback concept is well known also as the best solution for purity of sound reproduction without negative influence from feedback circuit. There is no any capacitor on direct or indirect signal path – unique construction.
Attenuation is based on 56pcs. high reliability relay (pure silver with gold plated contacts) network that is computer controlled – there is 96 position of attenuation and always is only one (single) laboratory grade resistor per phase on signal path.  
Magnetostat is equipped with basic function remote control unit made from solid block of aluminum.
Power supply section also speaks for itself. High capacity battery supply is used as the best solution for power section.
There are separate voltage regulators also for all additional (non signal path) stages.
Sound quality is totally independent from line voltage instability and influence of wide variety noises that could be coupled across.
Also, separate transformer supply digital circuit that control non analog signal preamplifiers function.
There is a built-in measurement for total hours of tube life accumulated that is presented by led diodes universal Meter (in decimal manner).
Quality of electronic material that is used inside Magnetostat is impressive – tubes by military and N.O.S. grade standard, 0.1% Vishay resistors, high quality transformer core, electrolytic capacitors for 105C of working temperature, gold plated Teflon isolated connectors, pure silver input wiring…
Line stage works properly at all world wide AC line voltage from 100 – 250 VAC, 50-60Hz (different transformers are used).
Design Features
– transformer coupled circuit (without any capacitor on direct or indirect signal path)
– absolute zero feedback design (unique construction)
– automatic recharge function
– custom designed wide-bandwidth output transformers
– fully balanced stabilisations for tube heaters and other purposes
– 6S31B-R special selected tubes (N.O.S.) and military grade in amplification section
– separate transformers for digital control and recharge function
– attenuation network form silent reed relay (56pcs.) – encoder rotation knob type
– remote control made from solid block of aluminium
– all modulated chassis that includes 4mm thick aluminium top cover
– built-in measurement for total hours of tube life accumulated
– Teflon insulated gold plated connectors  
– gold plated Teflon insulated RCA jacks with gold plated XLR balanced connectors
– hand assembled modulated chassis
– laser engraved front panel made from triple separate aluminum block of 20mm thick
– remote control made from solid block of aluminum
– extensively used computer numeric control machines (CNC)