AMR’s PH-77 – The world’s most flexible phono equalizer

After years of extensive in-house development and close collaboration with recording engineers and archivists from the BBC; the British Library Sound Archive; The Institut für Rundfunktechnik GmbH1 and Sveriges Radio AB2, AMR is pleased to announce it has commenced shipping of the PH-77 Reference Class Phono Equaliser3.

The PH-77 is the only phonograph source able to lay claim to exclusively feature a comprehensive catalogue of 22 equalisation (EQ) curves4: every LP record ever made may now be replayed using the one and only correct equalisation curve.

With unorthodox approaches to the circuit design, along with rare and primarily bespoke components, the AMR PH-77 Phono Equaliser paints a sonic picture that is so seductively vivid, beautiful and harmonically rich, it possesses an enthralling live performance-like quality that after listening, one is left struggling for superlatives.
Together with 8 levels of gain; 64 steps of load; 3 inputs for unprecedented flexibility in cartridge choice/matching and an onboard 24bit/96kHz Analogue-to-Digital converter, the PH-77 is undeniably, one of the most significant reference phonograph sources ever produced.

Complete Catalogue of 22 Equalisations Curves

Contrary to common perception, the introduction of the RIAA equalisation in 1954 did not result in the cutting of all LP’s to this standardised equalisation curve. In actual fact, even as late as the 1980’s, several significant record labels (including USA ones) continued to use equalisation curves that differed from the RIAA suggestion. With 22 different equalisation curves, for the first time, the PH-77 is one phonograph source that is truly able to correctly replay every record that has ever been pressed.

Unorthodox Signal Path Design and Bespoke Implementation

With an unusual approach to circuit design, the PH-77 is one of the most organic sounding phonograph sources ever made. The circuit is a pure single-ended, Class A, zero negative feedback design. All low-level signal connections including the cartridge are coupled directly. Overall, only two coupling capacitors are employed: one is a custom-made silver foil capacitor that follows the equalisation block; the other, the output capacitor, is the same German-made film and foil capacitor used in the multiple award-winning CD-77 CD-Processor. The circuit is designed to preserve absolute polarity at all gain levels and for all equalisation settings.

Further, the input stage was adopted from extreme low-noise circuitry used in quantum particle research. Along with only the highest quality of parts, the resultant equivalent input noise of -145dBV (0.056uV) places the PH-77 in the highest echelon of the quietest phonograph sources ever made.

Dedication to Purity of the Power Supply

The PH-77 uses sonically superior valve-based rectification with NOS EZ80 (2pcs) and double C-Core 20H choke filtering implemented fully dual-mono: for a quality of power supply that is quite literally, unequalled. Instead of traditional regulators, the PH-77 employs a far more elaborate set of 4 virtual battery supplies, characterised by zero negative feedback and lowest possible noise. These are followed by a further 28 stages of passive power supply filtering, 8 of them utilising costly large value film capacitors for the very highest sound quality.

Finest Matching and Unparalleled Adjustability

All of the following functions are completely adjustable in real-time either on the front panel or from the included aluminium remote control.

  • 8 levels of gain 72, 66, 60, 54, 48, 42, 36, 30dB for complete cartridge compatibility.
  • 64 steps(*) of load for pinpoint resistive and capacitive loading.
  • 3 switchable inputs to select the desired cartridges and tonearm combination: be it elliptical or spherical stylus cartridges; stereo or mono cartridges; fixed or flexible (linear tracking or pivoted) tonearms; with Moving Magnet or Moving Coil cartridges.
    (*)32 steps for Moving Coil, 32 steps for Moving Magnet.

    High-Resolution 24bit/96kHz Analogue to Digital Converter

    The PH-77 features a reference grade 24bit/96kHz** Analogue-to-Digital Converter. Through direct USB connection to a personal computer, this enables the transfer of vinyl pressings into the digital domain with the highest possible sound quality.

    The worldwide recommended retail price of the PH-77 is EUR7,800 (excluding VAT). You can expect to hear this model on demo in our showroom any day now!

    #1: Research centre of all German language public service broadcasters (ARD/ZDF/DLR), Austria’s ORF and the Swiss SRG/SSR.
    #2: Sweden’s Radio Ltd.
    #3: AMR first demonstrated the PH-77 prototype at CES 2008.
    #4: Equalisation on records has existed for over 80 years.

  • ph77_01s






    Related Links:

  • PH-77 Specifications   
  • PH-77 Owners Manual
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