Conrad-Johnson PF2L Line Level All-Analog Preamplifier
Simple yet capable solid state preamp from CJ made here in the USA.
Super clean cosmetically, plus on the test bench were it performed very well for its price.
Note that this is the "L" Line Level version of the PF2, which does *not* have a phono preamp section. The rear panel shows AUX/PHONO, but on the PF2 "L" this is only an AUX style standard line-level input.
More from Conrad-Johnson about the history of the PF1 + 2:
The PF1 was the first solid state preamp bearing the conrad-johnson name.
— Introduced May 1990, PF1L in August 1991
More than one decade of research and development led to the introduction of PF1.
The circuit design featured a unique distortion canceling circuit that resulted in excellent linearity without resorting to global negative feedback.
Independent discrete dc power supply regulators were used for each gain stage for absolute insolation between stages.
Parts quality was to conrad-johnson’s usual high standards. All capacitors, including power supply, were polypropylene and cjd polystyrene. There were no electrolytic capacitors in the PF1. All resistors were 1% metal-oxide deposited on glass construction resulting in very low noise.
The PF1 nicely combined the lucidity and harmonic balance of c-j vacuum tube preamps with the superb definition and detail of transistor designs.
The PF2 superseded the PF1.
— Introduced PF2L October, 1993 | PF2 December, 1993
The line stage circuits were virtually identical.
The PF2 offered an improved phono circuit, with selectable gain settings (40,46, and 52 dB). This made the PF2 better suited for use with low output
moving coil cartridges.
The PF2 maintained the exceptional parts quality standards of the PF1. Capacitors were polypropylene and cjd polystyrene including the power supply filter caps. All resistors were 1% metal-oxide deposited on glass construction. Input/output connectors were upgraded from those found in the PF1.
Noted for the lucidity and harmonic balance of the cj vacuum-tube preamps, the PF2 refined the achievements of the PF-1 with the superb definition and detail of transistor designs.
Aux/Phono - AUX Only on this PF2L
Rec 1 and Rec 2 outputs
Record (selects source for the Record outputs)
Gain: Phono Stage 40, 46, or 52 dB selectable (phono overload 65 mV at 1kHz)
Line Stage 20 dB
Distortion: less than .1% THD or IMD
Response: bandpass 2Hz to more than 100kHz
RIAA equalization +/- .25 dB (20 to 20 kHz)
S/N Ratio: Phono Stage 86 dB below 10 mv input
Line Stage 94 dB below 2.5 volt output
19″ x 3.315″ x 14 3/8″
The SkyFi Testing Process for Preamplifiers:
We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.
At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.
Final testing involves putting actual music through the preamplifier. We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage KEF speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.
Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.
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