AMR PH-77 Phonostage with Digital Output & Flight Case
Light scratch on front panel, otherwise excellent.
The PH-77 Phono Equaliser from AMR is a premium, high-spec vinyl player that puts the groove back into your vinyl. With its in-built Analogue-to-Digital audio converter, the PH-77 is one of the most sought-after vinyl players on the market.
here are excerpts of a steve hoffman review
This is the quietest tube phono stage I have ever heard and in addition to an RIAA EQ curve it has 22 others that are selectable on the fly by remote and has tons of cartridge loading options- including presets for hundreds of cartridges including my Van den Hul Colibri. From the manufacturers website:
Complete Catalogue of 23 Equalisations Curves
Contrary to common perception, the introduction of the RIAA Equalisation in 1954 did not result in all LP’s being cut using this standardised Equalisation Curve. 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. In addition, many original “all time classic” issues precede the widespread adoption of the RIAA Equalisation standard and so, require a particular equalisation curve.
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All such LP’s cannot be reproduced correctly with a phono stage offering only RIAA Equalisation. The PH-77’s OptiEQ allows the selection of 23 different EQ curves in real-time via remote control. This covers all known LP vinyl ever pressed, a true first among reference phono amplifiers.
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One may now finally listen to vinyl recordings the correct and original way such as:
The original Mercury Living Presence series (Decca FFSS, Decca FFRR EQ)
The original Deutsche Grammophon Classical records (Decca FFSS, Decca FFRR, CCIR EQ)
The original Miles Davis records (Columbia EQ)
Verve Jazz records, with performers like Charlie Parker, Count Basie, Ella Fitzgerald, Nina Simone and The Righteous Brothers etc. (Columbia & AES EQ)
The original Dave Brubeck Quartet records (Columbia EQ)
A significant number of the original stereo Decca (Europe) records (Decca FFSS, Decca FFRR EQ)
Rectify high frequency roll-off and excessive phase shift of all, including Neumann and Western Electric vinyl cutting lathes (Enhanced RIAA EQ)
This list* is far from comprehensive but sheds some light on how the magical musical performance of such coveted recordings has never been fully realised until now.
*: The labels on the list also issued many records based on the RIAA equalisation as well.
Unorthodox Signal Path Design and Bespoke Implementation
The PH-77 boasts only two gain stages that incorporate a total of 6 electron valves (3 per channel). It is a purist’s valve phono stage aimed at reproducing vinyl to the very highest level but with flexibility of adjustment of gain/load over a very wide range: The 1st Gain Stage is a hybrid comprised of one half which was adapted from "Advanced GAmma Tracking Array" (AGATA) pre-amplifiers designed in the UK. The other half is the NOS Mullard ECC81/12AT7 to form a fully direct-coupled stage with no negative feedback. Pure passive RC record equalisation2 (including the standard RIAA equalisation) is then performed using 26 silver foil coupling capacitors.
The 2nd Gain Stage uses the NOS Philips 5687WB electron valve for gain and to also provide a low output impedance for the PH-77 (<200Ohm). This stage has its cathode directly connected to the signal ground (no resistor or coupling capacitor). Bias is supplied by a fixed voltage. Following this, the signal is then passed through a directly coupled film & tin foil coupling capacitor of the highest quality to the output.
The PH-77 is a pure single-ended, class A, zero negative feedback design. All low level signal connections including the cartridge are coupled directly. Only two coupling capacitors are employed overall. One is a custom made silver leaf capacitor that follows the equalisation block. The output capacitor is the same German-made film and foil capacitor as 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.
All valves used in the PH-77 are rare NOS valves, e.g. Mullard ECC81/12AT7(2 pcs), and Philips 5687WB(2 pcs), EZ80(2 pcs).
The EQ section (including RIAA) is made up of custom-made silver leaf capacitors selected to less than 1% tolerance. For the standard RIAA EQ, all parts are directly soldered into the circuit using silver solder. The parts adjusting the historical curves are then switched into the circuit by gold over solid silver contact relays to ensure the best possible analogue performance with all EQ curves.
In order to ensure that any remaining dielectric effects in the capacitors are minimised, all capacitors carry bias voltages many times that of the signal voltage applied. This unusual approach operates the capacitors in a mode that is similar to single-ended Class A operation for amplifiers, to attain maximum linearity at incredibly low signal levels.
The end result is a signal path that preserves the purity of the music that is second to none.
Dedication to Purity of the Power Supply
The PH-77 uses sonically superior valve based rectification with NOS EZ80 (2pcs) and 2 x double C-core 20H choke filtering implemented fully dual mono, for the absolutely best possible power supply quality.
Conventional power supply regulation, valve or solid-state based, invariably uses negative feedback, which frequently results in sonic degradation of the signal circuit.
Instead of traditional regulators, the PH-77 employs a far more elaborate set of 4 virtual battery supplies, which are 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 very costly large value film capacitors for the highest sound quality.
The resultant power supply allows the delicate signal circuit to work unperturbed by any power supply issues, giving the PH-77 a supreme ability to convey the full dynamics and emotion of the music.
Finest Matching and Unparalleled Adjustability
In order to allow easy and precise matching of any cartridge, AMR has made the PH-77 adjustable using either the included aluminium remote control or via the front panel controls. The PH-77 offers:
levels of gain 72dB, 66dB, 60dB, 54dB, 48dB, 42dB, 36dB, 30dB for complete cartridge compatibility, optimally matching Cartridges with output levels from below 0.1mV to over 12mV.
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 tonearms, linear tracking or pivoted with Moving Magnet or Moving Coil cartridges.
High-Resolution 24bit/96kHz Analogue-to-Digital Converter For Storing Vinyl to Computer
The PH-77 features a reference grade 24bit/96kHz Analogue-to-Digital Converter for the highest quality transfer/archiving of vinyl to computer. This is achieved through a direct USB connection to a personal computer for preserving the integrity of the signal. This feature means the PH-77 is one of the most powerful phono sources with which to transfer vinyl pressings into the digital domain.
I have to admit a lot of that language screams of marketing-speak, but I can't argue with the sound.
From a review:
What struck me while doing A/B comparisons with the PH-77 and my reference ASR Basis Exclusive was the unprecedented clarity of the view into the soundstage. Hold on, let me refine that: more precisely, it was the unprecedented clarity of the reproduced musical content.
Because it wasn't simply a matter of more information: the ASR betters it in this capacity. It wasn't a matter of noise level, either: the ASR has the edge there, too.
Something else was happening beyond detail retrieval and noise level. There are things that plague analog playback, like tics and pops and scraping noises engendered by the stylus tracking the groove and out-of-phase ghost sounds coming from impossible locations. These telltale artifacts are so ubiquitous we take them for granted. I've yet to meet the analog front-end that doesn't have large amounts of a musical stuff competing with the signal; you always have to work through them. By the way, among other things, this is exactly what analog upgrades address. Whether it's a better table or arm or cartridge, all reduce these signature distractions.
Well, we should add phono stages to the list, for these artifacts are just what were eliminated with the PH-77. It passes less of these mechanical sounding distractions than any phono stage I've met. The upshot is the ratio of music to distractions tips way over towards more music.
How does the PH-77 accomplish this? For one thing, it cleans up some of the little things in the area outside the image. This is where most of the distractions live. For another, the AMR phono stage has a way of encapsulating images in discrete parcels.
Sound-Stage Holography
The last piece of the puzzle is the way the PH-77 floats those images in space. You get discrete parcels of dense tone hanging in air all around the soundstage. The spatial illusion is startling and tangible, as if they have 3-D coordinates. Compared to other units, the PH-77's sound-staging is High-Def.
