Audio Research PH3 Hybrid Tube Phono Preamplifier

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This is a wonderful and full-featured hybrid tube phono preamp from ARC. Tested in our lab and working perfectly.

Hard to beat the simplicity, warmth, and precision of this phono preamp that's made right here in the USA.

Tube Notes:
• The current tube complement is (3) Vintage Philips ECG JAN (Joint Army Navy) 6922.

Load Configuration:
• Default load resistors are present: 47K
• Default load capacitors have been removed, therefore setting the input capacitance to 40pF

If your cartridge requires a different load configuration, please contact us before making your purchase so that we can install the proper components for your cartridge.

Click below for our recommended RCA/Balanced XLR interconnect options, brand new from Kimber Kable (SkyFi is an official Kimber dealer).

Kimber RCA Interconnects

Kimber XLR Interconnects

Audio Research PH3 Tube Phono Preamplifier - Manual

More from Audio Research:

The PH3 is a phono preamplification stage intended for use with an active line-level stereo preamplifier. Fully single-ended from input to output, the PH3 uses a combination of J-FET input stage technology (for low inherent circuit noise) and class A operation vacuum-tube gain via three 6922 twin triodes. Total gain of the PH3 is 54 dB (non-adjustable). Used with typical line preamplifiers having 12 to 18 dB of gain, the PH3 is suitable for phono cartridges having .25 mV output or higher. Input impedance is factory-set at 47K ohms, and input capacitance at 90 pF. For optimal matching to moving-coil and moving-magnet phono cartridges, both input impedance and input capacitance may be adjusted via simple resistor and capacitor changes.

A resistor kit (with solder) is supplied for proper loading values between 30 and 800 ohms. Additional resistor values and capacitors may be ordered from the factory. On the rear panel, the PH3 provides one pair of gold-plated, audiophile-grade single-ended connectors for L & R inputs, and one pair for outputs. High-quality single-ended interconnects such as Audio Research LitzLink 2 brand are strongly recommended for best sonic performance with the PH3.

Hybrid stereo phono preamplifier

INTRODUCED
1995 (PH3).

MSRP (US NEW RETAIL)
PH3: $1,495. Increased to $1,695. Increased to $1,995 on Feb 5 2001.

SPECIFICATIONS:
FREQUENCY RESPONSE
±.15dB of RIAA, 10Hz to 60kHz.
3dB points below 0.5Hz and above 400kHz.

DISTORTION (THD)
Less than .005% at .50V RMS 1kHz output.

NOISE & HUM
0.1µV equivalent input noise, IHF weighted, shorted input (80 dB below 1mV 1kHz input).

GAIN
54dB at 1kHz (MC & MM compatible).

INPUT IMPEDANCE
47K ohms and 90pF Unbalanced.
(Provisions for any value below 47K ohms or added input capacitance for
matching certain magnetic cartridges.)

OUTPUT IMPEDANCE
200 ohms Unbalanced.
Recommended load 50K-100K ohms and 100pF.
(10K ohms minimum and 2000pF maximum.)

OUTPUT POLARITY
-

MAXIMUM INPUTS
60mV RMS at 1kHz (240 mV RMS at 10kHz)

RATED OUTPUTS
.50V RMS 10Hz to 60kHz, 100K ohm load (output capability is 30V RMS output at 1/2% THD at 1kHz).

POWER SUPPLIES
Electronically-regulated low and high voltage supplies.
Line regulation better than .01%

TUBE COMPLEMENT
(3) 6922/E88CC dual triodes with JFET input.
Solid state power supply.

POWER REQUIREMENTS
100-135VAC 60Hz (200-270VAC 50/60Hz) 28 watts maximum.
Line fuse 0.6A SLO BLO (0.3A SLO BLO 230V).

DIMENSIONS
19" (48 cm) W x 5 ¼" (13.4 cm) H (standard rack panel) x 10 ¼" (26 cm) D.
Handles extend 1½" (3.8 cm) forward of front panel.
Rear chassis fittings extend ¾" (2.2 cm)

WEIGHT
PH3: 10 lbs. (4.5 kg) Net;
19 lbs. (8.6 kg) Shipping. 

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.