Manufacturer: Gold Note PH10 phono pre-amplifier
UK distribution: Audio Pinnacle, (+44)1420 544140
Product: PH10 phono pre-amplifier with variable EQ
Price: £1096.00 + VAT (£1315 in UK at review date) YMMV
Reviewer: Mark Wheeler - TNT UK
Reviewed: Summer-Autumn 2017
Probably the most challenging task in the domestic audio amplification chain is the tricky business of preserving those tiny microvolts from the pick-up cartridge output and making them big enough and linear enough for a line input. Not only have massive amounts of gain to be applied to tiny signals emerging from even tinier coils, but this has to be applied in varying amounts according to frequency. Low frequencies, from 50Hz upwards need 6 dB per octave more gain than higher frequencies. That is more gain difference, between the low bass and the sensitive midrange, than the 21dB difference between 1W and 100W. In the UK and much of mainland Europe, 50Hz is where the mains hum is (similarly 60Hz in USA). It might seem odd then that we've agreed on a universal standard designed to magnify any induced hum in the playback system. The even more miniscule high frequencies, where the subtle nuances of performance, and the tiniest shimmering clues of ambience lie, alongside the subtlest higher harmonics of voices and lead instruments, benefit from least amplification to drag them above the amplification noise floor, in exchange for those tiny high frequencies being as far above the vinyl noise floor as possible. Even then, the subtlest higher harmonics of a musical instrument might be recorded with a groove wiggle in a similar order of magnitude to the size of vinyl molecules.
"Different vinyl LP pre-emphasis and replay EQ characteristics?" Question the Plebs' Chorus, stage left, in an incredulous but ironic tone, "What's all that about?"
The RIAA standard, by which modern records are cut, and its forebears, including the Columbia Standard and the Decca standard, all use recording emphasis and playback de-emphasis to overcome two primary limitations of cutting a wiggly slot into plastic to try to make a reasonable mechanical representation (or 'analogue') of a sound waveform (itself merely an analogue of compressions and rarefactions of air molecules). Its a wonder we hear anything from those 300mm discs of vinyl, let alone arguably one of the most viable formats for durable sound recording yet invented in this corner of our galaxy. RIAA means one thing to most vinylophiles, the standard by which most vinyl microgroove stereo discs are equalised to enact that groove squeezing principle. The RIAA equalization (EQ) characteristic was introduced in the 1950's to standardise what had previously been a plethora of competing EQ's. Three time constants were chosen, at three frequencies, 50.05Hz, 500.5Hz, and 2,122Hz create the pre-emphasis ('pre' because it is before the transcription to disc), requiring three matching de-emphasis time constants: 3180μS; 318μS and 75μS. This, if done correctly at both ends of the disc creation and reproduction chain, results in a flat frequency response with the minimum of extraneous noise. The RIAA record and replay equalisation were quickly adopted internationally, and duly became incorporated in IEC98 in 1964
Your Old Scribe remains intrigued at the numerous diverse solutions to phono pre-amplification, which is at least as diverse in approach as power amplification. Some argue that solid-state is quieter, some argue that fewer active devices in a valve circuit preserve the signal better. Some argue that only passive filter poles preserve high frequency timing due to reduced negative-feedback while others argue that active filters use fewer and smaller components. Some argue that only transformers can accurately match and raise the voltage of moving-coil cartridges, while others argue that only active devices like FET's can preserve phase accuracy at frequency extremes. What we have in the system today is the Gold Note PH10 phono pre-amplifier, an original approach to the high-end phono pre-amplifier that addresses problems rarely considered in the 21st century, while simultaneously attempting to maintain 21st Century performance and audiophile credibility, in a compact box. It succeeds, so reader, do read on.
As if all this close attention to EQ detail was not enough, Swiss research resulted in another time constant being added to the IEC standard, 7950μS, which created a playback only 6dB/octave rolloff at frequencies below 20.02Hz. The noble intention was to reduce the levels of infrasonic frequencies generated by record warps and ripples, exacerbated by the fundamental arm-cartridge resonance, overloading the amplification and loudspeaker chain, possibly in reaction to market dominance by reflex loaded loudspeakers supplanting sealed boxes as the predominant bass loading. Reflex, or ported loading, is prone to allow cones to flap about creating intermodulation distortion and dynamic compression with subsonic frequencies. As is obvious from the graph (courtesy Stereophile) this 7950μS pole affects the frequency balance all the way up to two G's below middle C (97Hz). This proved controversial among those interested in high quality reproduction, but remains written into the current IEC standard. Sometimes it seems as if the recording industry has an embedded institutional self-destruction, from the suicidal drug habits of its performers to the economically suicidal decision making of its management. The recording industry has consistently, since the 1970's, raced to the bottom in terms of sound quality. With vinyl they sought the lowest common denominator in reproduction quality from flimsy vinyl with a degraded playback EQ. Then they offered the abomination that was musicassettes, a format designed solely for dictaphones, and so handy for people to make free, equally lo-fi, copies. Then they offered a digital disc via a digital disc format (CD), that was less than half as good as what was possible at the time, and even easier to make free copies of equal quality. Finally they achieved the ultimate (so far) idiocy that is MP3 so easy to copy and stream that few have ever paid for it.
Not confused yet? In addition to this, two decades ago, when attempting to design a DIY phono-stage, your Old Scribe purchased Allen Wright's excellent amplifier design handbook, The Tube Preamplifier Cookbook. In it, the founder/designer/CEO of Vacuum State Electronics put forward a coherent argument for yet another tweak to the venerable RIAA/IEC playback EQ curve. Wright proposed a correction for a response error identified in the most commonly used master cutting lathe, the Neumann. The so called 'Neumann correction' was to mitigate their lathe design decision to limit ultrasonic frequencies in the cutter heads, because they're unnecessarily for the audible bandwidth and merely generate heat and waste cutting head amplifier power-bandwidth. So this is effectively another filter pole, above 50kHz, or 3.18μS either to correct the frequency response, or the phase response, depending on which commentator you believe. The AQvox 2Ci does have this extra pole and the Canor TP306 VR+ does not. Both are differently excellent and neither prove the case, one way or the other. The differences between them are probably far greater for other reasons than ultrasonic bandwidth. The Gold Note PH10 does offer an opportunity to hear the same circuit in both configurations. However, selecting the 'Neumann correction' 3.18μS EQ option also selects the IEC 7950μS, rumble filter. One end of the bandwidth goes up while the other comes down.
Other authors, Keith Howard, for example, argue that the correction does not match that shown in Neumann's specifications (a classic Butterworth 12dB/octave from a similar frequency) and is therefore the wrong approach to correction. Others argue that the extra components are more detrimental that the primary error. Yet another group (exemplified by Bill Dyer) argue that the phase errors created by numerous I/O transformers in mixers and audiophile passive crossover loudspeakers would overwhelm these tiny phase errors. What matters is can we hear.
Gold Note, with their PH10 is One example of a manufacturer trying to cover all the bases and rectify the industry imposed vinyl limitations. The Gold Note PH10 phono pre-amplifier is a small object of desire. Hewn from solid billet aluminium with a red LED glow from the interior when on standby, this is a product that shrieks Italian style with the banshee wail of a V12 superleggera. By contrast, the Gold Note PH10 then backs this style up with the gearbox options of an old twin stick truck.
For much of the review your Old Scribe was under the misapprehension that the Gold Note PH10 would be around 2 grand. Listening notes were made on that basis and the Gold Note PH10 was pitched mercilessly against the standard of the Canor TP306 VR+ and the notes from the current amplification AQvox 2Ci. In the UK, the Gold Note PH10 is priced at £1096.00+VAT (£1315) and they're determined to hold this price "despite the political turmoil" caused by the UK so-called 'Brexit' policy. A network of dealers is being sought in the UK and Eire, so dear reader, you might be able to audition one in a dealer demonstration.
Your Old Scribe soon had some questions to ask the designers, once listening began.
In an exchange of emails, back and forth between Old Scribe and Gold Note, we learn:|
Who designed the circuits?
What is the philosophy behind the circuit decisions?
How are the filter poles achieved and at what time constants?
Is the 'enhanced' EQ the usual Neumann (Hagerman & Wright et al) 3.18us (50kHz) and/or the 7950us low end IEC high-pass pole?
The variable input resistance is very welcome, why not variable input capacitance for the moving magnet options (e.g. Decca/London cartridges benefit from 22k but need more than typical parallel capacitance, depending on model)?
How was the configuration chosen and what was the philosophy behind the decision to offer alternative historical EQ alignments?
When will the outboard PSU be available?
There are two RCA inputs so two turntables or arms might be connected simultaneously. Each input can be configured differently to match each cartridge. It is high time the antiquated, unsuitable, make live-before-earth RCA plug and socket were expelled from the shores of quality audio (at least Naim tried unsuccessfully to convert the world to impedance matched BNC plugs), but Gold Note have to fit the things that every pick-up arm manufacturer uses. There are nine cartridge loading options on each input of the Gold Note PH-10. Then that cartridge output can be matched by four different selectable gain levels -3dB, 0dB, +3dB, +6dB. Thus the two inputs may be closely matched to each other and to the line levels of other sources, whether driven by MM or MC cartridges.
The inductive nature of the coils in cartridges (regardless of which bits move: magnet; coil; iron; earth etc) means the nine different load options 10Ω, 22Ω, 47Ω, 100Ω, 220Ω, 470Ω, 1000Ω, 22KΩ, 47KΩ will all sound different. For example, Decca London cartridges blossom with 22kΩ and most moving magnet cartridges are good with 47kΩ but many moving coil cartridges sound more powerful at an order of magnitude lower Z. Once the cartridge is optimised, the replay characteristic EQ can be optimised for historic discs with different pre-emphasis and replay characteristics. Now the Gold Note PH10 user may select the correct EQ characteristic for every disc, between the internationally recognised RIAA, DECCA-LONDON or AMERICAN-CBS-COLUMBIA curves,
Only then might they choose to add the IEC and Neumann corrections , selected simultaneously using the "enhanced" setting of whichever EQ is chosen. This Gold Note claim, is by their "cutting-edge" cutting lathe correction proprietary technology to "improve listeners' vinyl experience". We shall make our minds up based on listening. However, Gold Note have even used modular design to enable further developments to be retrofitted, covering any future developments. These will include, they say, an External Inductive Power Supply, a Curve Equalizer Extender unit, and Class-A Tube Output Stage and Gain Stage Enhancer. The inductive power supply is eagerly awaited. Several manufacturers (especially in the UK) have used power supply options to create a hierarchy of improvements, while maintaining a core family sound. If 'inductive power supply translates as a choke regulated linear supply, big improvements in bass quality and PRaT may be expected.
The Gold Note PH10 case is machined from solid aluminium. The shell construction minimises low frequency resonance and vibrational feedback control. The eddy currents present in non-magnetic aluminium resists the influence of magnetic fields (perhaps from poorly orientated transformers) and the case is an effective Faraday cage. The single knob control is an unusual technology that works with the TFT display to enable rapid control of the unit's functions through the "single knob joggle" (not a phrase I ever expected to type). The display shows information clearly and looks great.
The press and hold knob that controls all but the primary mains supply is the simplest human interface of any high end audio product this reviewer has encountered. From this single knob, which activates the unit, to selecting gain, EQ, cartridge load and recording constant, this single knob does it all. A sustained push connects the dormant power supply to the audio circuits. A twist changes the parameter to be varied. Another push chooses that parameter. A further push alters the dimensions of that parameter and a third push selects the chosen level of that parameter. The interface has all the qualities of a good single lever tripod head, with a twist of the handle for vertical movement and two twists of the handle for horizontal movement while maintaining mechanical integrity. Your Old Scribe has two tripod heads of the same brand and vintage, one single handle, 2-stage twist grip, all accurate metal construction, and one typical modern polycarbonate two handle plus knob (horizon tilt, vertical tilt, horizontal rotation) and guess which usually got left behind in the studio when heading for a job?
"Get on with it," Complain the Plebs' Chorus, stage left, "What does it sound like?"
The Gold Note PH10 presents a precise local acoustic. In a multitrack recording, the local acoustic of each performer is often still present. Even in a multitrack recording where some compression has been applied to each instrument track and then some overall compression to the final mix, the information can be there, available to high resolution systems. Providing that compression has not been overdone in either individual tracks or the final stereo mix, the local acoustic can still be audible around each instrument. What is needed in the reproduction chain is adequate bandwidth and adequate dynamic range. This zone of the dynamic range is not the top end of the dynamic envelope, the upper 6dB of available dynamic range of CD's into which a lot of modern music is recorded. Allen Wright, the aforementioned designer of many all valve phono stages, coined the phrase 'downward dynamic range'. It is the lowest available level of the signal, just above the noise-floor and tailing off into it, that counts to achieve this. Even when a signal is at a similar level to the noise-floor, it reacts with the noise, intermodulating it. This downward dynamic range is often inaccurate, but far better inaccurately present than completely absent. The Gold Note PH10 manages this trick very effectively, in a manner different from the Canor TP306 VR+, but still present. The Canor achieves spectacular ambience by immaculate phase preservation while the Gold Note PH10 manages better downward dynamic range instead.
Little Feat's Cold Cold Cold (Sailing Shoes) has a clear vocal booth audible space around Lowell George's vocal line distinct from the mic feed from each vocalist. Checking his preferred recording protocol, Lowell would let the band get on with it, watching and listening from the control room (totally different from Van Vliet's Beefheart practice) then adding his own vocal track on top. The Canor TP306 VR+ offers a bigger picture but more vague, as though a slightly lower degree of resolution has been magnified to a greater extent than the Gold Note PH10.
The Gold Note PH10 is capable of BIG sound despite little soundstage depth and height and no extension beyond the loudspeakers, like a typical flat earth (e.g. Linn/Naim) presentation. The dynamic envelope of each note is faithfully reproduced. The dynamic shape of every piano note is well preserved as it decays into ambient information. There is no exaggeration to snare drums, In the manner of the old Naim MC K boards, while thinking about Flat-Earthiness.
The Gold Note PH10 offers clarity and precision in a flat soundstage. Despite the lack of 3 dimensional its of the soundstage, every instrument is clearly delineated and the listener can follow each individual instrument in even the densest of mixes. Carlos Santana's Moonflower includes so many densely mixed tracks full of musical, information that adds up to so much more than the sum of its parts that it can be difficult (or superfluous) to identify individual contributions. The Gold Note PH10 succeeds in making either possible at the whim of the listener.
'Front end first' is the philosophy that information retrieval is paramount and information lost at any stage in the audio chain cannot be regained later. Raw information comes in many forms in musical reproduction. That is why there are so many approaches, all vehemently defended by their designers, to getting music from recording venue to listeners' ears. The shallow depth and average (for its class) width soundstage, with offered by the Gold Note PH10 may not impress the kind of audiophile who thinks "Never mind the quality, feel the width". The Gold Note PH10 seems most adept at preserving subtle musical information. The listener who commented "You can hear the inside of his guitar" in response to the Canor TP306 VR+, was impressed with the musical performance revealing qualities of the Gold Note PH10. The enhanced power supply may improve the soundstage scale.
Bass precision is good enough to let listeners know when it's a Precision Bass. The enhanced power supply, to be available later this year, should take this further. Counter intuitively the Gold Note PH10 copes with heavy bass despite its standard tiny power supply and massive gain. We therefore look forward even more to evaluating the promised big PSU (power supply unit). Vocals and instruments in a similar range, like cellos, violas, guitars, saxophones etc maintain their power and integrity, even when heavy bass is present.
The variable EQ does not lead to tone-control exaggeration nor does it seem to compromise transparency unnecessarily. However, the enhanced option often seems lightweight sounding, despite extended ultra high frequencies being reported in psychoacoustic research to improve bass quality. Standard RIAA accuracy was preferred consistently. Deliberately selecting the wrong EQ sounded like the effect of the 'Tilt control' on the Quad 44 pre-amplifier. Briefly amusing but ultimately not satisfying.
Despite all the tweakability of the Gold Note PH10 phono-stage, or perhaps inspired by it, the PH10 proves an ideal evaluation tool. It enables rapid optimisation of whatever is connected. Its obsessive attention to accurate EQ led, by association, to other thoughts about pressings.
The Gold Note PH10 phono stage was sufficiently revealing to leave it in place when reviewing Divinyl LP cleaner. undisturbed by pops and clicks, the PH10 was an ideal vehicle to transport listeners between 'before' and 'after' conditions, without exaggerating the differences. This phono-stage's immunity to overload from spits, pops and crackles helped make an objective comparison. Changing gain settings did not upset it during the Divinyl test, even on the highest gain setting, the 'before' condition discs did not upset the Gold Note.
The Gold Note PH10 was used to compare the two most commonly available pressings of Frank Zappa's 'Ship Arriving too Late to Save a Drowning Witch' and modern vs old pressings of The Who's Who's Next for a future article. The Gold Note phono-stage was also pressed into service to evaluate a service and re-tip of a Linn Basik turntable and Audio Technica AT95E & Linn K5 cartridges. At no time did it seem necessary to replace the Gold Note with other phono pre-amplifiers costing over twice as much.
The Gold Note PH10 is one of the most competent and comprehensive phono pre-amplification stages on the market. That it achieves this status at a key price point, rather than in cost-no-object territory, is a remarkable achievement. The manufacturers were very keen to get this out to review as soon as possible and it is easy to understand why. This is a very special audio component that will fit the contexts and priorities of many system owners.
This review compared the Gold Note approach with the completely different approaches of both the AQvox 2Ci and the Canor TP306 VR+. The former uses the uncommon approach of fully balanced currant amplification while the other uses characterful active devices (6SL7) and purely passive RIAA EQ de-emphasis. Neither could be more different in approach. More conventional approaches from companies like Naim (solid state), Audio Research (heavily regulated valves) and others all aim to achieve the same goal of extracting the maximum musical enjoyment from the tiny signal at the cartridge pins. All choose their own set of compromises because no one can please all of the people all of the time.
Gold Note, with the Gold Note PH10 effectively manages its own attempt to please as many of the people for as long as possible. This phono pre-amplifier punches above its crowded price point. On top of that it adapts to whatever cartridge the listener is using this month, so it is future proofed against cartridge upgrades. The promise of upgrade accessories implies it is future proofed against being upgraded from purchaser's systems.
Uniquely, the Gold Note PH10 manages to be past proofed in its capacity to match the historic pre-emphasis EQ of archival record collections. At this price point the Gold Note PH10 is unique in its achievements.
Copyright © 2017 Mark Wheeler - firstname.lastname@example.org - www.tnt-audio.com