Manley Labs OASIS Phono Stage
MPN #OASIS Phono Stage
Steel chassis, precise RIAA equalization, low-noise FETs for amplification, 6922 vacuum tubes, user-selectable gain and loading, flexible cartridge compatibility
The logical successor to the legacy Chinook, our new OASIS Phono Stage deploys our modern dedicated power supply and construction to usher a new series of Manley preamplifier designs to your home. Named after one of our dearest Mastering Studio partners, the OASIS carries forth the clean and precise audio circuits of the prior Steelhead and Chinook audio paths into a new age of high fidelity preampfification offerings from Manley Labs.
Like the Steelhead, each channel employs the two triode sections of a 6922 for amplifying duties assisted by low noise FETs receiving the signal below each cathode. Highly accurate passive RIAA equalization networks perform the decoding task to restore the originally intended frequency response to the audio signal. In the Oasis, the signal passes through no Integrated Circuits. There are ICs deployed in a servo configuration to apply a precise biasing voltage to the Gate of each FET, and you might notice some other chips who are performing some LOGIC functions to direct the turn on and shut down sequences invoking the MUTE relays to prevent unwanted bumps or noises when the unit is power cycling. Importantly, the signal is directly coupled from the gain stages to another 6922 dual triode serving as the output driver in a White Follower configuration. This output stage circuit is our favorite because of its super-low output impedance and beefy current-driving capabilities. It can drive long cable lengths and difficult loads, tube or solid-state. Bring it on. No wimpy cathode followers here!
The chassis is a new powder-coated over zinc passivated steel design which will be shared amongst 3 other upcoming new Manley preamplifiers. Through this efficiency we have splurged a bit and created a more luxurious housing with its large-radiused substantial top cover sporting smooth rounded side edges. Rounding out the casework, the frontal face is adorned by a 3/8" thick CNC milled facia with an intricately inlaid contrasting "racetrack" insert for visual interest. The OASIS moniker is laser-engraved into the oblong island on the façade. By popular request we have made the faceplates available in traditional "Manley Blue" aka "Pewter Grey" or Black.
Setting up the Oasis is easy and requires no entry into the interior of the unit. On the rear panel you will find all the switches that you need to optimize your cartridge interface to the Oasis. Depending on the nominal output level of your cartridge, GAIN can be set to 45dB, 50dB, 60dB or 65dB of amplification. These GAIN choices will accommodate all Moving-Magnet and Moving-Coil cartridges. The back panel also contains DIP switches for adjusting the input resistive and capacitance loading values. 31 possible options between 26 and 800 Ohms plus 47k Ohms and 7 capacitive loading choices between 50 pF and 350 pF provide flexibility to match any cartridge and fine tune the tone. Set it and forget it! Audiophile-grade and time-proven componentry is used throughout, embodying Manley's dedication to seductive sonics, combined with the reliability that professionals around the world depend on. At just about a quarter of the price of our revered Steelhead preamplifier, the Oasis maintains focus on elegance of design, careful execution, efficient construction, and appreciable quality.
Designed and built in California, the Oasis exemplifies Manley's commitment to our local community and to a simple, clean, and quiet signal path. The Oasis demonstrates the supreme linearity of vacuum tubes while providing the flexibility needed to embrace any turntable setup. Everything from the most exotic 180 gram audiophile pressing to 25 cent thrift-store classics will be reproduced accurately and musically.
Features
Vacuum Tube Complement: 6922 x 2 (gain stage) plus 6922 x2 (output stage). Any 6DJ8, 7308, ECC88 types may be used.Unbalanced Input and Output connections via Manley Teflon & Gold plated RCA jacksAutomatic Mute Timer: On initial power up output jacks are muted for approximately 45 seconds. Automatic mute circuit allows tubes to warm up and circuitry to settle. At power down, output jacks are immediately muted.Input Termination Capacitance: 3-position user-selectable capacitor values of 50pF, 100pF, and 200pF yield resultant combinations of: 50, 100, 150, 200, 250, 300, and 350pF. Use these settings typically for Moving Magnet (MM) cartridges.Default Input Impedance: 47k Ohms, with no other DIP switches selected. Use this setting typically for Moving Magnet (MM) cartridges.Selectable Input Impedance: 5-position user-selectable resistor values of 50, 100, 200, 400, and 800 Ohms. There are 32 possible loading possibilities. Use these resistive loading choices typically for Moving Coil (MC) cartridges.
Specifications
Gain: Rear Panel DIP switches select 45dB, 50dB, 60dB, or 65dBDeviation from RIAA curve: Less than ± 0.5 dB from 20Hz to 20kHz at any gain setting. Typically less than ±1dB from 10Hz to 100kHz.Distortion (THD+N) (47k Ohm Input Termination, 45dB gain, 1kHz sine, 0dBu output): Typical 0.010% THD+N, into 100k Ohm load, BW = 100Hz-22kHzDistortion (THD+N) (47k Ohm Input Termination, 45dB gain, 1kHz sine, 0dBu output): Typical 0.030% THD+N, into 600 Ohm load, BW = 100Hz-22kHzDynamic Range (Gain set to 45db, 200 Ohm source): 91dB @ 1kHz, 0.1% THD+N, BW = 22Hz-22kHzDynamic Range (Gain set to 45db, 200 Ohm source): 107dB @ 1kHz, 1.0% THD+N, BW = 22Hz-22kHzNoise Floor at 45dB gain setting with shorted input: -84 dBu, A-weightedNoise Floor at 60dB gain setting with shorted input: -75 dBu, A-weightedMaximum Input at 45dB gain setting with 20 Ohm Source Z @ 1kHz into 10 kOhm load: 250mV RMS = +34.5 dBu @ 1% THD+N BW=22Hz-22kHzMaximum Input at 60dB gain setting with 20 Ohm Source Z @ 1kHz into 10 kOhm load: 40mV RMS = +34.2 dBu @ 1% THD+N BW=22Hz-22kHzMaximum Output: +37dBu @ 1kHz, 1.5% THD+N into 100 kOhm loadOutput Impedance: 91 OhmsMinimum Recommended Load: 2500 OhmsInternal Switch Mode Custom Power Supply: Fully regulated B+, Heater, and control voltage rails.Operating mains voltage: 90 to 254 VAC (internal universal supply)Power Consumption in Standby mode: 1 Watt (8.0mA @ 120VAC)Power Consumption: 42 Watts (345mA @ 120VAC)Mains Voltage Frequency: 50~60HzDimensions: W=17", L=14", H=3 1/2" (Occupies 2RU)Shipping Box Dimensions: 23" x 18" x 7"Shipping Weight: 20 Lbs.
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