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PH50 phono stages for moving magnet cartridges

  • Phono stages for moving magnet cartridges
  • Ultra low noise transformerless design
  • Variable high-pass filter to eliminate rumble
  • Plug and play easy to set up and use

The Hafler PH50 is an ultra-linear phono stage for moving magnet (dynamic 47k-Ohm) cartridges that exhibits less than 0.5dB deviation from 10Hz to 100kHz and boasts a well defined RIAA curve to preserve and transmit the original program material with minimal coloration. Particular attention has been applied to reducing noise, a problem common to the 33 RPM recording chain, resulting in a low -82dB noise floor with greater than 91dB of dynamic range and less than 0.002% distortion.

The design begins with a 14 gauge steel casing to shield the low level signals from external magnetic fields and RF contamination. Gold-plated input and output RCA connector pairs are employed that will not tarnish over time, thus optimizing signal flow. Inside, the solid-state circuit and military grade PC board have been optimized by carefully positioning parts for minimal self-noise and cross-talk and then supplemented with a ground plane to reduce susceptibility to RF and external magnetic fields. An external supply further reduces noise by removing the power transformer from inside the casing.

Front panel controls include a power on-off switch and a variable low-cut filter that may be inserted into the signal path when needed. The fully djustable low cut (high-pass) filter enables the user to reduce low frequencies that can cause resonance and feedback when playing music at higher levels. This helps eliminate both airborne and solidly coupled transmission of vibrations that can disrupt the stylus and cause feedback, rumble and distortion.

Compact yet 'plug and play' easy to use, the PH50 follows Hafler's 50 year tradition of building the very finest audio products.

Dial In

  1. Power
    Turns on the PH50
  2. Low Cut
    Inserts low cut filter into signal path
  3. Variable Low Cut Filter
    Eliminates rumble from excessive bass

Connect

  1. RCA Inputs
    Connects from the turntable to the PH50. Features 47k-ohm standard input for moving magnet cartridges. Gold plated to eliminate tarnishing and ensure optimal signal transfer.
  2. RCA Outputs
    Line level output connects to preamp or receivers' -10dB line input. Gold plated to eliminate tarnishing and ensure optimal signal transfer.
  3. Ground Lug
    Standard round spade connector for the turntable ground attachment. Features knurled stainless steel thumbscrew for easy manipulation.
  4. Power
    Connection for the external 15V power supply. Features cable lock for added security. The power supply is included.

Inside

  1. Low-noise, Ultra-linear Circuit
    To optimize signal transfer, the PH50 employs metal-film resistors along with full-sized capacitors that are hand inserted to deliver the very best audio quality.
  2. Double Sided PCB
    Through-hole solder points combine with a military spec circuit board for greater durability. A full surface ground plane reduces susceptibility to radio frequency interference.
  3. Extra Durable Switches
    Ultra high quality switches and potentiometers employ steel casings and metal shafts for long-term reliability. Switches rated at over 20,000 cycles.
  4. Steel Casing
    Made from virgin steel, the folded U-shape design provides a solid frame for the sensitive PC board to eliminate torque, which could lead to premature cold solder joints. Also provides excellent shielding against RF and tray magnetic fields.

Specs

Audio circuit type:Active operational amplifier
Frequency response:RIAA curve
Total harmonic distortion (THD+N): 0.008%
Dynamic range:91dB
Input impedance:47K Ω
Maximum input:-21dBu
Gain:35dB
Clip level - output:+12dBu
Output impedance:400 Ω
Equivalent input noise:-79dBu
Noise floor:-79dBu
Intermodulation distortion:0.04%

Features

Controls:Low pass cut off
Switches:Low pass ON, power
Low-cut filter:20Hz to 500Hz
Filter Slope:12dB / Octave

FAQ

Can I connect a moving coil cartridge to the PH50?

No. The PH50 is designed for moving magnet (dynamic) cartridges. For moving coil designs, the Hafler PH60 is the proper choice.

What is the advantage of the PH50 over a built-in phono stage?

Unlike most built-in phono stages that are ‘side attraction to the main show’, the PH50 was conceived from the ground up to deliver great sound with low noise for a more exciting and natural experience.

Can I bypass the RIAA equalization curve inside the PH50?

No. It is built into PH50 and is part of the circuit board.

Should I be concerned with the length of the cables I use?

High impedance cables are generally more prone to picking up noise from radio frequencies and magnetic fields. Thus keeping the cables shorter is beneficial. As a rule, try to keep the output cables from the PH50 under 2 meters (6‘) in length.

Why does the Hafler PH50 employ an external power supply?

The low output from a turntable requires a lot of gain to bring it up to a suitable level. This also makes the circuit much more prone to noise. The transformer in a power supply generates hum which if not kept in check can generate noise. By moving the power supply outside the casing significantly reduces noise.

Can I connect the PH50 to my iphone to transfer my albums?

Yes, as long as you have a stereo input on your phone or portable music player. Most audio dealers can supply you with a dual RCA to mini 3.5 TRS connector which would be used to send the signal from the PH50 to your portable device.

Does the impedance on my dynamic cartridge matter?

No. Standards have been established for years with dynamic cartridges so that they all work within a prescribed range. You simply plug in and you are set to go.

Reviews

Novo Magazine

The more I listened through the Hafler PH50 the more I became convinced of its great ability to drive musical engagement. While it doesn't extract the minutest of details, it does capture the essence of the performance, relaying a believable and lifelike interpreation that favours pleasantness over exacting detail.

George de Sa

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audioxpress

The PH50 is exceptionally quiet - literally a silent partner during my listening sessions. At full preamp gain, with my ear up to the speaker (no music, of course!), there's just a trace of hiss. It offered clean, detailed sound with reasonably good soundstage information and dynamics."

Gary Galo

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