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  The Model 7LX3.5 Line Level Preamplifier (the top unit in the photo) is designed for the person seeking the ultimate in a neutral but dynamic line level preamplifier. Designed as a control center for both digital and analog based systems, the 7LX3.5 makes an ideal companion to the 7PX3.5 and shares many of the same design and construction features. The exceptional naturalness of the 7LX3.5 preserves all the subtle nuances of the source material and enables it to mate equally well with either vacuum tube or solid state amplifiers. The sonic neutrality of the 7LX3.5 rivals the best of the passive controllers but easily out-performs these units in dynamic contrasts and ability to drive long cables while also providing balanced output capability for amplifiers having balanced inputs.
   
• Both balanced and unbalanced outputs for total system flexibility (see input option below).

• Separate "listen" and "record" circuits provide ultimate flexibility of signal routing. An input "Off" position for both circuits allows isolation of recording equipment or preamplifier when either is not in use.

• One of the five line level inputs provides factory installed options as follows:
Model 7LX3.5 - an unbalanced line level input via Oxygen Free Copper RCA phono connectors.
Model 7LX3.5/B - a balanced line level input via XLR connectors.

• Separate L and R channel input level controls set the input impedance of the unbalanced inputs. Wired in shunt and normally operated in their maximum (or near maximum) positions where no current flows in the wipers, these controls allow for both L/R channel balance and source attenuation without perceptible sonic degradation.

• Volume adjustment is achieved by a true stepped attenuator having laser trimmed resistance elements for precise channel tracking.

• An auto-mute circuit using FET switches provides a 30-second turn-on delay by clamping the outputs to ground during initial turn-on, in the event of a momentary power failure, or where the line voltage is too low to maintain proper DC regulation. A two-color LED indicates the state of the auto-mute circuit at any time. The mute circuit can also be manually activated with the front-panel mute switch. In this case, a logic circuit allows immediate defeat of muting, yet prevents false resetting if there has been a recent power interruption.

• Discrete inverter circuits provide both balanced and unbalanced outputs with optimum sonic performance for both types of amplifier inputs. Balanced output signals are available via both XLR and OFC RCA connectors.

• All outputs are direct coupled to eliminate the need for large blocking capacitors in the signal path. DC offset is maintained to plus or minus five millivolts with DC servo circuits operating outside the signal path. All inputs and outputs are protected with shunting diodes.

• The bottom panel is made of dense .25 inch thick Corian® composite for high acoustic stability and low electric field interaction.
   
Gain: 14 dB Unbalanced; 20 dB Balanced.

Bandwidth: 0.1Hz. to 150KHz.

Input impedance: 25K Ohms unbal. inputs with input level control set to max. 15K Ohms with input level set at min. (25K per side for balanced input of model 7LX3.5/B.)

Output impedance: 300 Ohms Unbalanced. 300 Ohms per side Balanced.

Finish: The Chassis is finished with a black Polyurethane paint with a light texture. The Face Panel is anodized, in either black or platinum gold. The Side Bars are black lacquered Ash with a semigloss finish.

Dimensions: The 7LX3.5 is 2.5 inches (6.4 cm.) high, 19 inches (48.3 cm.) wide, and 11.58 inches (29.4 cm.) deep.

Weight: The preamplifier weighs approximately 15 pounds. The power supply weighs 3 pounds, and total shipping weight is approximately 20 pounds.
   

  The Model 7PX3.5 Phono Preamplifier (the lower unit in the photo) is designed for the person seeking the ultimate in phono reproduction. A complete stand-alone phono preamplifier with an external power supply, it can be used with a line level preamplifier, a digital preamplifier with an analog line level input, or a passive switchbox controller. Like that of our other audio components, the sonic character of the 7PX3.5 emphasizes musical naturalness rather than the overly dramatic “high fi” sound with exaggerated definition and consequent fatiguing high-frequency reproduction. The exceptional neutrality of the 7PX3.5 enables it to mate equally well with either vacuum tube or solid state preamplifiers.

Consistent with our commitment to a musically natural sound, all signal amplification is accomplished with our discrete proprietary circuits potted in modules labeled Music Module™. While we hold technical excellence in the highest regard, our final choice in circuits and components for the Music Module™ is based on their ability to accurately reproduce the correct tonal and harmonic character of music itself. Furthermore, each Music Module™ is constructed and adjusted for its particular function in the circuit.

All critical passive parts in the 7PX3.5 (jacks, wire, resistors, etc.) have been selected on the basis of extensive listening evaluation in our own reference system and are chosen primarily for their ability to yield the most transparently natural sound at all frequencies. (Some of the parts are extremely expensive aerospace components rarely used in consumer grade equipment.)
   
• RIAA Equalization is passive using the very finest parts available.

• The external power supply uses a toroidal transformer with a capacity approximately 5 times the actual preamp power consumption. It provides filtered dual-polarity DC power to the main chassis via a shielded power cord and a premium-quality screw-lock connector.

• Internal power-supply regulation is accomplished with three precision cascaded levels. The first level provides ripple and line transient filtering, and locks to a nominal DC level. The second and third levels use individual precision feedback regulators for each channel which independently feed the first and second amplification stages via “star” networks. This trilevel regulation system, consisting of a total of ten independent regulators, provides a very high level of channel separation.

• Main outputs are direct coupled to eliminate the need for large blocking capacitors in the signal path. DC offset is maintained to plus or minus three millivolts with DC servo circuits operating outside the signal path. All inputs and outputs are protected with shunting diodes.

• Separate buffered tape outputs are provided for the ultimate purity in taping cherished analog pressings directly to either analog or digital tape recorders without the need to route the signal through a companion preamplifier.

• The Model 7PX3.5/B includes a factory installed balanced output option (similar to the Model 7LX3.5).
   
Gain: Adjustable at 36, 50, 64, or 66dB at 1 KHz.

RIAA accuracy: +/- 0.2 dB at 1.0 VRMS out.

Bandwidth: 0.5Hz. to 150KHz.

Input impedance: Resistance is adjustable from 100 to 47K Ohms. (User selected resistors allow any value between 0 and 47K Ohms.) Capacitance is fixed at 150pF.

Output impedance: 300 Ohms, both main and tape outputs.(300 Ohms per side balanced-7PX3/B only)

Finish: The Chassis is finished with a black Polyurethane paint with a light texture. The Face Panel is anodized, in either black or platinum gold. The Side Bars are black lacquered Ash with a semigloss finish.

Dimensions: The 7PX3 is 2.5 inches (6.4 cm.) high, 19 inches (48.3 cm.) wide, and 11.58 inches (29.4 cm.) deep.

Weight: The preamplifier weighs approximately 12 pounds. The power supply weighs 3 pounds, and total shipping weight is approximately 20 pounds.

As we continuously engage in research to improve our products, we reserve the right to make changes in specifications and prices without prior notice or obligation.