Sunday, May 24, 2009
Rega P5 revisited
I had blogged on my Rega P5 recently. It was more on the excitement and a certain degree of unsureness over its acquisition, set-up by a first timer (and that's me), sound quality in general, addition of some third party upgrade parts and how the acrylic platter transformed the sound. This is a follow-up, zeroing into the subject of subplatter and other areas omitted earlier.
What's in a Rega turntable? Having lived with a P5 for 7 months by now, I find it downright simple with minimal parts count and build quality rather basic. I'd rate it as musical sounding though, especially its rhythmic flow and ebb of music which inadvertently set listeners' feet to start tapping and the bringing out of air guitar from nowhere into play. There are many other turntables out there capable of sounding more accurate, dynamic and three-dimensional than the Regas but most are either not musical enough or beyond my reach. A review on both P5 and P7: http://www.stereophile.com/turntables/1204rega/ and a forum discussion on Rega P5: http://www.zerogain.com/forum/showthread.php?t=7041&page=1&pp=15
Rega turntables are deliberately tuned to run slightly faster to attain the famous British rhythmic bounce which is not only highly addictive but renders listening a pure joy although Roy Gandy purportedly denies such allegation. In my opinion, the subplatter (the small flywheel beneath its main platter that holds the belt from motor pulley) in a P5 and lesser models which is cast from mold and made of phenolic (definition here: http://www.wisegeek.com/what-is-phenolic.htm) is the weakest link and has 2 obvious imperfections. Firstly, it is not perfectly round and attributed to higher 'wows & flutters', thereby affecting pitch stability. Secondly, its diameter is a tad smaller and caused speed (measurable by stroboscope and light at certain frequency) to run faster than 33 1/3 and 45 r.p.m. and compromises focus/absolute clarity. See footnote below. The subplatter in P7 and P9 is made of aluminium alloy and a perfect round; its exact diameter not known but I suspect it is same as the phenolic unit in lesser models. Rega hides the slight lack-of-focus with their selection of material for their platters, ie. glass for P3-24 and P5 whereas ceramics for P7 and P9. Both these materials share some common sonic traits – they ring, emanate a bright and pitchy sound and require damping with felt mats; they also tend to emphasize more on the mid bass and this complements the British pop and rock music well. Rega's apparent lack of enthusiasm in vertical tracking angle adjustment could probably be interrelated, as lower VTA translates to the suppressing of excessive brightness.
The tonearm fitted to P5 is RB700, an identical tonearm as the much acclaimed RB300 but finished in silver colour, fitted with tighter tolerance bearings internally and needs to be three-point mounted. Its design is again basic and would benefit from upgrades like counterweight replacement and/or Incognito rewiring to further enhance its performance. Many third-party companies produce replacement counterweights with each offering a different design philosophy, fit 'n' finish and attention-to-construction detail. I replaced the stock stainless steel counterweight with Michell TecnoWeight, a well crafted and reputed to be the best of the lot counterweight - its centre of mass at stylus level improves tracking and minimizes stylus/record wear (I also found the RB700 tonearm more sophisticated). Its use requires the disabling of spring-loaded vertical tracking mechanism of Rega tonearms and enables accuracy of 1/10th gram adjustment in VTF. Audible improvements include better extension to both frequency extremes and a better defined three dimensional soundstage. Full details here: http://www.vinylengine.com/michell-tecnoweight.shtml
I also replaced the stock glass platter and mat with a 24mm thick acrylic platter sourced from Deutschland. What I heard with it are detailed in full in my posting on Analogue Source - Rega P5 turntable. Another obvious benefit unrelated to sonics is that my newly cleaned records would remain clean with no mat around. Do allow me to enthuse on my use of a 190g acrylic record puck instead. I had been rather lazy all these while and the truth is I hardly make use of any of my three different record weight/puck/clamp (a made-in-USA Locus Design 340g stainless steel BasiClamp record weight (subsequently sold to a hifi acquaintance), a made-in-Germany Delta Device 190g acrylic record puck and a made-in-England Michell record clamp). The primary purpose of a record weight/puck/clamp is to flatten warped records by coupling them to the platter and this minimizes mistracking and prevents the damaging subsonic rumbles (the gyration of loudspeaker woofers when warped records are played). Some listening sessions lately with the 190g acrylic record puck reveal a subtle but real enhancement to sound – a darker background, less graininess with instruments sounding more vivid and palpable apart from the sound of being dampened – fuller, weightier and reduced sibilance; more of the "on steroid effect" akin to switching from a 16 bits normal CD to a 20 bits XRCD. Its downside is a slight loss to pace, rhythm and timing; and perhaps this could be reason why Rega does not encourage the use of any record weight/puck/clamp on its turntables. An interesting read on use of medium weight record clamp: http://www.soundfountain.com/amb/puck.html
A transparent dust cover is supplied with every Rega turntable; its use is what its name suggests, ie. to keep dust away but its presence on the turntable could adversely affect the sonics from vibrations induced thereof. See excerpt of the review of P7 in HiFi Critic of UK which confirms this: "Straight out of the box. P7 (fitted with Exact MM cartridge) stepped in at 47 marks. ……. Everything was 'good', not remarkably so, just well ordered, stable confident, easy on the ear and on the mind. Bass was quite tuneful and flowing; low bass was a mite lean. The stereo soundstage was stable, well focused and with good image width and depth. Treble was sweet and notably tidy. The Rega P7 would certainly have passed muster with the moderately priced Exact, but the 10X5 further confirmed its credentials. Installing the Dynavector cartridge led to a mildly rougher sounding treble than with the Exact, but the unmistakable improvement in bass crispness, overall dynamics and front to back clarity of the more costly MC cartridge was quite apparent, resulting in a gain of 8 marks. A decent test score of 55 was awarded with no dissent, but installing the lid (operated closed) resulted in a 12 point drop to 43 marks, in our view."
The subplatter is an integral part of Rega turntables and affects how they sound; the phenolic unit in a P5 and lesser models is clearly a compromise. The solution would be to replace it with a precision machined third party subplatter. At present, Groovetracer™ seems to offer the best 3-piece-assembly subplatter with the main hub machined from 6061-T6 aluminum, its bearing axle is hardened RC62 ground steel and the record spindle machined and polished from stainless steel. The benefits, extracted from Groovetracer's website, include lower coefficient of friction between the bearing surfaces and minimizes vibration for a lower noise floor, the record spindle is decoupled from the bearing axle to further reduce vibration transfer to the playing surface, three point Delrin interface in Reference model between the subplatter and platter ensures positive contact and also minimizes vibration transfer, 0.001"or better concentricity between the axle and hub offers vast improvement in pitch control, and extended length record spindle (14mm) permits the use of clamps like my Michell record clamp.
My Groovetracer Reference subplatter arrived from the States in immaculate condition on 28.05.2009. It was double-boxed and well cushioned by small pieces of polystyrene inside both boxes. Frank Smilie or his staff sure did an excellent job in the packing and paid attention to every single detail. He responds to e-mails promptly too. Kudos to Frank!
The installation of the subplatter and Zirconia ball is pretty straightforward with Frank's simple but well-written instructions. I found the diameter of Zirconia ball larger than Rega's 4.74mm steel unit. No measurement was made though. Once done, I noticed that the bottom section of my acrylic platter is raised up by 2mm from the Cherry wood surround of my P5 (I've added a 2mm thick brass spacer to the bearing assembly on top of the plinth so as to elevate the acrylic platter from the wood surround), then it struck me that Groovetracer supply their own 26mm thick acrylic platters whereas thickness of the unit I am having is only 24mm. The length of bearing axle of the subplatter must have been custom built to cater to their acrylic platter and not mine. It appears that I should now remove the 2mm thick brass spacer to regain the correct VTA. (PlS: I did removed the spacer but the increase to height of the acrylic platter is inadequate to dispense with it altogether. It was refitted after a good and thorough polish with Brasso.) The top plate of the stainless steel section (just below the spindle) that fills up the centre hole of the acrylic platter is recessed by another 2mm with same result expected from the use of Rega's 12mm glass platter. Hmmm... I was hoping that it'd be at same level. A sapphire thrust plate is integrated into the bottom end of the bearing shaft; this must be good stuff! The stainless steel spindle, with diameter of 7.15mm, gives a loose fit (as opposed to interference fit from Rega's phenolic spindle) to records. My acrylic platter spins smoothly without the slightest wobble, unlike when used with Rega's phenolic subplatter. Excellent!
Listening impression - The first LP I listened to with my new subplatter is Ben Webster – At the Renaissance, a recording made in 1960 and reissued by Analogue Productions. I immediately noticed loudness of the music to be a tad softer with volume set at my usual listening level. I cranked up the volume and my system soon gained more details and dynamic contrasts. This should be what people termed as lower noise floor! What I heard further: voices of people talking in the background (akin to those at the beginning of Limehouse Blues in Jazz in the Pawnshop album) of this LP are more discernable, instruments sounding leaner with better precision (as opposed to fat, bloated and vague previously). The high frequencies are slightly lesser but I perceived the sound to be more natural that I did not miss any treble diminution. I spinned the Aaron Copland & Gian Carlo Menotti - Piano Concertos's LP next. This LP, being a new digital recording and a low serially numbered original pressing by Analogue Productions, sounds pretty impressive as usual with dynamics, dynamic contrasts and immense clarity of instruments so apparent that would easily put many decent-sounding CDs to shame. I checked out my P5's new PRaT capability by listening to Money for Nothing in Dire Straits – Brothers in Arms's LP before I called it a day. The result: absolute speed and the rhythmic bounce are without doubt a tad slower than before. What I gained instead are precision, neutrality and music sounding more natural.
I picked up an used but mint copy of Michelle Pan (潘越云) - 情歌 unplugged version of 原音再现 LP recently. Before the subplatter change, I thought it's quite a lemon with its sound almost muted, lowly resolved and with extremely low gain. What captivated my interest though, are the content of the LP – her songs and the way how they were rearranged and sang. A quick spin before leaving for work this morning highlights the prowess of new resolving capability of my P5. The sound opens up tremendously and live instruments are easily discerned with its resolution now not very far from a CD. One word to describe this: Amazing!
The Groovetracer Reference subplatter is not cheap; its full costs inclusive of air mail postage and 3% PayPal surcharge exceed the price of a brand new Rega P1 turntable in Malaysia with enough change to pick up a brand new record. Its sonic benefits though, are clearly superb and a-must-have for all Rega turntables. The precision build and materials used combine makes it the best subplatter, better than the unit in P7 and P9. In my opinion, the performance of my upgraded P5 now could be easily be equaled to turntables costing twice its costs and of all the upgrade parts. Two turntables immediately came to mind are VPI Scout and Clearaudio Performance. I consider myself a music lover first and a keen audiophile later; I am prepared to forgo focus/absolute accuracy if such an improvement is gained at the expense of absolute PRaT and overall musicality, the very reason why I find turntables tuned to highlight bass, bass weight, slam and attack on percussions unmusical to my ears - they are all about dynamics and excitement. Rega turntables (and few other British makes) stress on the rhythmic bounce which draw us into the music and enable us to listen for many fatigue-free hours. The sonic improvements brought about by the change to Groovetracer subplatter are clearly not about gaining dynamics and excitement. The rhythmic bounce may be a little lesser but at the same time I've gained abundance of resolution, finesse and further naturalness – music sound unforced and flowing!
Footnote:Q: How does the Rega stock subplatter which is slightly smaller in its outer diameter measurement affect the sound?
A: Smaller diameter attributes the subplatter to spin faster and consequently music sound faster, full of vitality and more appealing to our ears (as we concentrate on the bigger picture rather than the details). Spin too fast and we'll hear the Chipmunks effect. The downside is some lack of clarity and details. Disbelieve? Check out the different speeds on an open reel tape player for proof. To attain correct speed, the outer diameter of the subplatter must be enlarged and details would snap into focus. We get to see more vivid details including clearer outline of the main object(s) as we attain perfect focus just like photo shots with SLR cameras.
Reply from manufacturer:
I'm glad you received your subplatter in good order. I will point out a couple of key notes on your review that come to mind:-
Firstly, the zirconia ball is only 0.02mm larger than the stock Rega unit and will not affect anything dimensionally that would alter the function of the bearing. The difference is miniscule to say the least.
Secondly, the stainless steel spindle diameter is the most common diameter used today. I can only assess that your stock Rega spindle is slightly bulged due to the inconsistent press fit with the stock subplatter assembly. If you take it apart you would see what I mean. Actually, the fit is the same as 95% of hi-end turntables I have ever encountered. This is the way records are supposed to fit, not tightly coupled to the spindle. I guess it is personal preference when it comes to this but believe me, it is a lot better than having to make spindle holes in LPs larger.
Third point on the "critical" dimensions of my subplatter are all that matter and mimic that of the stock Rega unit so you can use it with any platter you wish to place on it. We want the record playing surface level to be the same (or within a few thousands of an inch) which is the most important feature. I see that the manufacturer of the acrylic platter you own sent you a 2mm spacer to raise the bearing assembly to clear the plinth. I make an acrylic platter specifically for the P5 that doesn't necessitate the implementation of a spacer. I'm sure that you raised the tonearm by 2mm to offset this anomaly.
The final point I will make is that the sapphire thrust plate which is integral with the bottom of the bearing shaft has a huge influence on the performance of the bearing assembly. The precision build and materials used combine to give you the best subplatter available today for your Rega. I am glad you are happy and over the next several hours after the bearing runs in, you will become increasingly pleased, I'm sure. I think you will be very happy with the performance of your P5 now. It should keep you interested in playing records for many years to come. Thank you again for taking the time to comment on your purchase.