Audio Research PH8 audio amplifier
Contents
1. TECHNICAL SPECIFICATIONS Type Tube Transistor phono stage for MM MC pickups Origin US designed and made Features One set of unbalanced inputs One set of unbalanced outputs Stereo mono switch Variable cartridge loading Mute button Frequency response 2dB of RIAA 10Hz to 60kHz 3dB points below 0 3Hz and above 400k z Distortion Less than 005 at 50V RMS 1kHz output GAIN 58dB at 1kHz MC amp MM compatible Push buttons Power Mono Load Mute Input impedance Selectable 47K 1000 500 200 or 100 ohms with 200pF Unbalanced Output impedance 200 ohms Unbalanced Recommended load 50K 100K ohms and 100pF 10K ohms minimum and 2000pF maximum Output polarity Non Inverting Maximum inputs 7OmV RMS at 1kHz 180mV RMS at 10kHz Rated outputs 50V RMS 10Hz to 60kHz 100K ohm load output capability is 50V RMS output at 1 2 THD at 1kHz Power supplies Electronically regulated low and high voltage supplies Line regulation better than 01 Noise 0 2UV equivalent input noise IHF weighted shorted input 74 dB below ImV 1kHz input Tube complement 2 6H30 dual triodes with JFET input 6550 and 6H30 as HV regulators Dimensions WxHxD 47x13 2x30 5 cm D Rear chassis fittings extend 1 5 cm Weight 6 8 kg Net 10 5 kg Shipping Price 6 299 Manufactured by Audio Research Corporation URL www audioresearch com Distributed by Absolute Sounds Tel 44 0 20 8971 3909 URL www absolutesou2. EQUIPMENT REVIEW Audio Research PH8 Phono stage u ith so many reasonably priced phono stages reaching a pretty high standard is it really necessary to spend this much on Audio Research s PH8 Sadly the answer is yes don t know about you but if was stumping up this sort of dosh for a phono stage d want nay demand something downright amazing with absolutely knock out orgasmic sonics from the first moment you hear it I d want to be blown away by a sound that is clearly superior to what already have The improvement would have to be blindingly obvious not something you have to listen carefully for but an obvious immediate gain in performance But is that a realistic expectation even given the massive price tag of the PH8 Sure the PH8 is bound to be good it s from ARC nuff said But doesn t the law of diminishing retums apply with a vengeance to products like this Maybe all one should expect is a subtle improvement over a good but more realistically priced phono stage Yeah right Such were the thoughts that ran through my head as got the PH8 ready to roll removing the top to fit the tubes Affordable Well sort of Actually to keep things in perspective it needs to be said that the PH8 is not the best phono stage Audio Research make That honour goes to ARC s Reference 2 The PH8 is intended as a more affordable version of the latter Of course the term affordable is used he
3. extra something EAT to the Beat Using the impressive EAT Forte S as our front end the PH8 created a big solid richly detailed sound that was notable for its spacious dimensionality and tonal opulence Dynamic range was wide and the music emerged from an inky black silence It was akin to listen to CD in so far as there was no audible surface noise or background hiss At the same time the music sounded freer and more natural than CD with a wider range of tone colours and greater subtlety Timing seemed better too so that rhythms were more tightly sprung with greater forward momentum Put simply the music and performance sounded truer and more real as though you were listening to real people playing live The PH8 is a fabulous phono stage in every sense incredibly good sonically and hugely aspirational It s such a pity the cost is so high since it means only a lucky few will ever get to own such an amazing price of kit Life is so unfair But if you can afford the asking price definitely go and audition a PH8 We think it will significantly improve on your existing phono stage almost irrespective of what it is and what it costs and probably leave you amazed and impressed The way it brings your vinyl to life is incredible You ll go through your collection hearing old favourites as never before which is great Only trouble is you may not fancy listening to CD afterwards There had to be a downside hike 57
4. idges you d need to set the impedance to 47k Ohms But MC cartridges can be used at any impedance Frisky The 47k Ohms setting should deliver the brightest liveliest sound but if the top end is AUDIO RESEARCH PH8 PHONO STAGE a bit too frisky selecting a lower impedance should help meaning you can fine tune things to get the best results from your chosen pickup A stereo mono switch is provided very important for those who play old mono LPs Switching to mono cancels output caused by vertical motion of the stylus and has the effect of significantly reducing pressing rumble and noise The PH8 is very revealing yet not in a destructive manner It always makes the most of whatever signal you feed it with so you hear what s right with your recordings rather than having the bad things emphasised Here s an example While comparing a couple of high end turntables using another phono stage we noticed that one of the decks clearly revealed that two guitars were playing at a certain point in a track With the other lesser turntable this detail wasn t quite so obvious However with the PH8 in the driving seat you could clearly hear two guitars being used with both turntables In a sense the PH8 almost reduced the difference between the two decks making both sound utterly fabulous For years now we ve had it drummed into us that the source component is dominant holding the key to superior Sound quality Yet the extra someth
5. ing delivered by the PH8 almost made the absolute quality of the turntable seem less crucial Turntables Who needs em This represents something of a paradox l m not saying you can use any old turntable with the PH8 a chain is only as good as its weakest link But the need for the front end to shoulder the full burden of responsibility is much reduced Tonally the PH8 delivers a fairly rich warm sort of sound full bodied and weighty Detail is amazing but never in the sense of it seeming etched or forced Things sound smooth natural and impressively holographic Bass is solid and powerful the mid band open and liquid the highs brilliant and incisive but sweet Best of all there s an impressive three dimensional out of the boxes soundstage that suggests real depth and space Bandwidth is unusually wide with 3dB points below 83Hz and above 400kHz On paper this makes the PH8 potentially sensitive to sub sonic audio research LOAD 100 OPERATE itis 55 noise and rumble However in practise there should be no issues given a good turntable Distortion levels are extremely low and gain is a useful 58 dB making the PH8 is sufficiently sensitive for use with low output moving coil cartridges You could even use an MC step up transformer without risk of overload Bring on the Billington had a Billington MC transformer to hand and tried it with impressive results With most MC phono stages you wo
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7. re in its relative and comparative sense The PH8 remains an extremely costly piece of kit and will probably be beyond reach for many enthusiasts But it s still an exciting and interesting product It borrows some of the Reference 2 s technology but features solid state J Fet input devices rather than the four 6922 tubes used in the Reference Coupling cap types and circuit board material are common to both products Straight from the box Audio Research warn that a long burn in period is required before new equipment sounds at its best Our review PH8 already had hihi 53 a few miles on the clock and proved to be immediately impressive In typical ARC style the PH8 produces a big rich deep sound that has massive scale and depth It s a very solid tactile sort of presentation there s nothing small or effete about the sound The music sounds focused and very present The PH8 has a fixed gain of 58dB Overload point is a massive 70mV at 1kHz making it suitable for virtually any pickup on the market fixed or moving coil We used a Koetsu Urushi Sky Blue a medium high output MC pickup There was plenty of level and background noise was very low Those with ARC preamps like the LS 27 would be able to vary the gain of the line input stage to create a comfortable listening volume In order to tailor the phono stage to your cartridge the PH8 offers variable input impedance When using fixed coil MM cartr
8. uld not be able to use a step up transformer due to problems with impedance and overload But with the PH 8 it worked well We got a much bigger soundstage with greater scale and wider dynamic contrasts The sound had enhanced depth and much increased presence Even at a low setting of the volume control the sound effortlessly filled the room The inputs and outputs on the PH8 are single ended with variable impedance loading 47K 1K 500 200 100 ohms plus Stereo Mono and Mute buttons A choice of silver or black front panels is offered The vacuum fluorescent display offers eight selectable brightness levels The display can be switched off but nine small pixels remain dimly lit so you know your PH8 is still powered up AUDIO RESEARCH PH8 PHONO STAGE Usefaully all these functions are accessible via the supplied remote control so changes can be made from your listening chair There s even a tube meter so you know how long the valves have been in service While the Reference 2 might deliver even better sound quality the PH8 gets quite close to its more expensive sibling Near enough perhaps for many to consider the difference in price to be too high to justify in terms of the improvement offered Certainly when coupled with a good tumtable arnm cartridge the PH8 makes listening to vinyl hugelyrewarding No matter how good your digital source CD SACD or hard drive might be LPs still offer a certain
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