Manley Labs Neo-Classic 300B RC Tube Preamplifier

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General:
The Manley Neo-Classic 300B RC is a full vacuum tube stereo preamplifier featuring 2 x 300B output tubes, 2 x 6SL7GT input tubes, 2 x 5AR4/5U4G rectifiers, and 2 x OD3 voltage regulators.

Manley Labs is an interesting company on the market as they produce high-end hi-fi stereo gear alongside professional audio equipment for recording studios. Much of their experience in the pro audio sector bleeds into their hi-fi gear and vice versa, creating a cool dynamic and exceptionally neat products.

The Neo-Classic 300B RC is a standout in their range with a beautiful fit, finish, and retro-modern aesthetic. Standout features include a motorized ALPS audiophile volume control, pure Class A output topology, and custom-designed output transformers wound directly in Manley's own magnetics department.

For the avid headphone fans among us, this preamp also has you covered. This model utilizes a dedicated headphone amplifier rated for a massive 1W (1000mW) into a 600-ohm load, complete with a 3-way impedance selector switch. This provides an incredible amount of distortion-free power on tap for cans that require it.

In testing we were impressed by its

Included will be its original RF remote control, manual, and box to make this a complete set for the next owner.

SkyFi Cosmetic Notes:
Unit is in great condition, Very minimal signs of wear. The included manual is a printed copy, not an original document.

From Manley Labs:
Experience the Manley Neo-Classic 300B RC, single-ended triode preamplification
The Manley Neo-Classic 300B RC Preamplifier employs the 300B triode as a dedicated line driver in single-ended Class A configuration, combining vacuum tube rectification and regulation with advanced ripple rejection circuitry for exceptional noise floor performance. Hand-assembled in California, this all-triode design delivers the transparency and dimensional imaging characteristic of zero-crossover-distortion amplification while providing comprehensive source integration and remote control functionality for modern high-fidelity systems.

Pure Class A triode topology with tube-regulated power supply
The preamplifier architecture maximizes the linearity and bandwidth of the 300B triode in single-ended operation. Vacuum tube rectification and regulation, combined with proprietary ripple rejection topology, achieve exceptionally low noise performance essential for resolving micro-dynamic information and spatial cues. The all-triode Class A signal path maintains phase coherence and harmonic accuracy from input to output, ensuring faithful reproduction of source material without solid-state artifacts.

Integrated headphone amplification with impedance optimization

The 300B output stage functions as a dedicated Class A headphone amplifier, delivering 1 watt into 600 Ohm loads with exceptional current drive capability. A three-position impedance selector optimizes output matching for headphones ranging from 30 Ohms to 4000 Ohms, ensuring proper damping factor and transient response across all driver types. This topology provides reference-grade headphone performance directly from the preamplifier without additional amplification stages.

Comprehensive connectivity with motorized remote control
System control is executed through a precision motorized ALPS volume potentiometer operated via omnidirectional RF remote, providing wireless functionality through walls and cabinetry. Five line-level inputs accommodate multiple sources, while a dedicated unbuffered record output and post-volume subwoofer output enable flexible system integration. The Neo-Classic 300B RC serves as a complete analog control center for discerning high-fidelity installations.

SkyFi Technical Notes:
This preamplifier has been fitted with a mix of tubes. Vintage USA Regulators, JJ Rectifiers, and Russian preamp and line driver tubes. The 300Bs line drivers are Elecrto-Harmonix Gold Pin.

Ownership:
Single Owner

Connections:
RCA Inputs and Outputs, IEC Power

General Sound:
Smooth, uncolored, undistorted natural and clean

Cosmetic Condition:
8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. See our detailed rating description here.

Working Condition:
Working perfectly and tested in our lab and listening room.

Included:
Unit, Box, Manual, Power Cord, Remote

Packing:
Original Manufacturers Packing

Original MSRP:
$7,999.00

Specs:
Tubes
2 x 300B, 2 x 6SL7, 2 x 5AR4 (Rectifier)
Inputs
5 stereo pair Unbalanced RCA
Max Output
+17.2 dBu (Line Stage)
Headphone Power
1 W into 600 Ohms
S/N Ratio
105 dB typical (A WGT)

Dimensions:
19" W x 13" L x 4" H (Top Deck)

Weight:
28 lbs.

Link to Manual:
Click Here

Recommended Cables:
Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

Testing Process:
We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface.

The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1 KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope.

We then switch to a 1 KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment.

Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected.

If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.