Click here to to see Utopia Line Stage photo gallery.

Utopia Direct Coupling Dual Mono Vacuum Tube Remote Controlled Line Stage represents top of the Line Stage segment in NAT audio equipment. NAT is really proud to present line stage with no coupling capacitors or inter-stage transformer on signal path, yet zero feedback concept. Sound is treated only with vacuum tubes and hi quality small value resistors.

Utopia is a vacuum tube dual chassis line stage preamplifier in full dual mono configuration. First chassis called Control Unit contain power supply, digital controls and all other modules. Line Stage is second chassis, which contain only analog circuits.

LINE STAGE CIRCUIT: Unique all triode zero feedback configuration makes this low output impedance preamplifier capable to drive any kind of power amplifier. Long life military grade tubes 6N23P-EV (E88CC equivalent) & 6N6P/6N30P-DR special low impedance triode are used in line stage circuit.

Volume control is realized with 16 high reliability relays. Contact material of these relays is silver with gold glad. By relays switching combination volume control can be adjusted in 100 steps.

ANALOG POWER SUPPLY started with two custom-made low-density toroidal transformers. All needed voltages are regulated with 11 stages per channel(22 stages in total). Anode voltages are double regulated for each analog stage.

Control Unit Chassis contain two high quality input AC filters one for analog power supply transformers and one for the digital supply.

Micro-controller Based DIGITAL CONTROL CIRCUIT controls all necessary functions of preamplifier, and its current status is displayed on an alphanumerical front panel. Front panel is made of twelve dot matrix displays. Digital Control Circuit is supplied with custom-made low-density toroidal transformer (totally three transformers per unit). Remote control unit made from two pieces of solid block aluminum controls all preamplifier functions.

	NAT Audio has  review for Utopia Direct coupling Line Stage and Magma M Mono Block Power Amplifier in Italian audio magazine "Fedelta" April 2010. edition. Click here to download original review (Italian) (256 kB) Click here to download original Cover (329 kB) Click here to download review (English) (640 kB) Click here to download review (German) (630 kB)
	NAT Audio has cover page & review for Utopia Direct coupling Line Stage and Se2Se Mono Block Power Amplifier in Netherland audio magazine "Home Studio" nov/dec 2003. edition. Click here to download original review (Dutch) (1471 kB) Click here to download review (English) (531 kB) Click here to download review (German) (545 kB)

Frequency Response

DC to 500 kHz, -3 dB; 20Hz to 20kHz, +/-0.00dB @ 47 kohms

Noise

90 dB IHF ref. to 1 Vrms output

Gain

15 dB(x5.6) Phase status: invert (180 degree)

THD & N

< 0.1 %

Input Impedance

> 27 kohms

Stereo Separation

> 95 dB @ 1 kHz

Tube Complement

4 x 6N23P-EV, 2 x 6N6P/6N30P-DR; all military grade

Output Impedance

< 80 ohms @ DC to 500 kHz

Power Requirements

110 VAC or 220 VAC @ 50 to 60 Hz, max. 80 VA

Dimensions (Control Unit)

19" (483 mm) wide x 10.4" (265 mm) deep x 5.5" (140 mm) high

Dimensions (Line Stage)

19" (483 mm) wide x 10.4" (265 mm) deep x 4.3" (110 mm) high

TOTAL Weight

approx. 55 lbs. (29 kg) packed in wooden box