Technics SP-10 mkII speed adjustment question
"As for Artisan Fidelity, their plinth is a copy of mine and I resent that." Not so fast. Although Mr. Porter's tale makes for good story telling, anyone with a fastidious eye for detail and a keen memory should be able to spot immediately what classic Technics design was the near aesthetic duplicate of "yours". For those interested in investigating further, search Technics SH-10B3 Obsidian plinth on Google. Once a suitable image is located, note the familiar beveled edge angles (top and bottom) and armboard location and shape. Now, if one were to imagine this plinth's center slightly taller and a slightly longer armboard.....you get the idea. An original exterior design, yes, only by Technics circa 1980 or so. This base criteria also served as a personal design concept of mine on paper, long ago. Constrained layer damping in mechanical engineering is a practice which has been utilized in various industries, even audio for decades. Panzerholz, again, not invented or conceived by the poster above. Furthermore, the internals of these two respective Sp10 designs differ substantially. The method of cld layering, applied isolation, bonding, materials used, finishing techniques and implementation as a whole vary to a significant degree. The principal similarities of the plinths in question are almost solely aesthetic in nature. While we are sharing openly, inquisitive readers might also be interested in researching Artisan Fidelity's once unique practice of thick outer plank wrapping over a constrained layer core. This practice has been embraced by AF from the start and only later copied by certain others. If anyone is curious as to why another might suddenly switch their approach from thin to thick panel wrap, just ask, the whole story is an enlightening one, that much I can assure you. And the sudden offerings of Sp10Mk3's with aluminum chassis refinishes? A "copy" perhaps of our long standing practice or merely coincidence? The list goes on, but why bother.... Where credit is due on Mr. Porter's behalf, in my humble opinion, lies in helping bring to light the vast potential of these particular direct drives of a bygone era, the Technics Sp10Mk2 and Mk3 which were once overlooked by many, primarily as a result of poor implementation. (ie. plinth design) In this capacity, this individual has served as an inspiration to both myself and others. This includes the fundamental approach of Panzerholz core based plinths in conjunction with the above stated models. Artisan Fidelity's core substratum methods employed for Panzerholz based and conventional style plinths have been proprietary since day one for each individuals set design requirements and tailored uniquely for each make and model. For anyone following our work, never have our aesthetics for the Technics Sp10 remained static and based solely around the vintage factory SH-10B3 Obsidian plinth or "Porter" style in question. Moreover, our latest Sp10Mk2 and Mk3 next generation design efforts build upon knowledge learned through previous conventional design approaches and are a significant departure from either. Never has Mr. Porter made an effort to approach me privately regarding his feelings on the Sp10 plinth style matter, instead he wishes to continually express his thoughts in a contriving manor on public forums. Perhaps had he contacted me early on, and made the choice to discuss things directly like a professional, as a like minded audio enthusiast, we could have avoided these unpleasant and unnecessary forum antics. Time to put this to rest. |
Albert, I wonder if your objective in your plinth design was to "sink" vibrational energy rather than synchronize ("sync") it. But maybe synchronizing vibration frequencies for turntables is related to British thin-walled speaker cabinets? ;^) But seriously, with Lbeichev's question, I might guess that Technics engineers did make their best effort to design a suitable plinth -- for that point in time. If one checks back they will see Technics designed and offered a total of four different plinths for their SP-10 series of motor units and three out of four increased mass over the predecessor. The point is that much has been learned since the '70s when there were designed and sold. Just look at developments over the last 5-6 years in rim-drive turntables (Garrard, Thorens, Lenco) and how their performance has been improved. I suspect the current interest in DD tables followed what was learned with rim drive units (meaning mass and stability). |
Lewm et all, Sorry, I missed this thread initially. I have heard the SP-10 mklll with Krebs mods. In fact I have it in my system currently. I had some mechanical issues getting the table reinstalled in it's current Artisan Fidelity plinth but having resolved those it's running very quietly. I'm very happy with it's performance at this point. I also have a mklll in a Dobbins plinth which has been my reference as far as silent operation is concerned. I would say the performance of the two tables is very similar at this point. It's hard to imagine better vinyl playback or machines more user friendly in everyday use. Which would I recommend? Both. If carried out to their ultimate endpoint, both designs are reference quality in my opinion and a winner would be hard to chose. It may depend more on the look you're after. Hope this is helpful in some way. |
Albert, Why do you think the Technics engineers were able to make the best turntable, but they were not able to design a suitable plinth? For the same reason Technics did not know to do the Krebs mods which raise speed stability and improve transparency and dynamics. There are precious few products manufactured 25 years ago that cannot in some way be improved through modern materials and technology that simply was not available back then. |
Sonofjim (Kent), I'm surprised that all the phone calls and email messages we exchanged you never mentioned the mods done by Bill. Are you saying the two tables are almost the same performance (with and without) the mods? Your tests certainly did not result in the same outcome as here. Also, Bill explained the issue you had with noise on the (non) Dobbins version of the MK3. That was a huge noise generator easily wiping out any benefit of the mods. |
Lbelchev - Why do you think the Technics engineers were able to make the best turntable, but they were not able to design a suitable plinth?I think the answer to your question is probably explained by the end use of the product. The Technics was primarily going into radio studios - hence the drop into a top plate/plinth makes sense. Conversely the Kenwood L07D and Exclusive P3 were primarily intended for domestic use, they did not have to consider dropping their TT into a DJ or studio worktop. |
Sonofjim Thankyou for your positive comments regarding my upgrade. It is gratifying to hear that you like the results. Bill does a great job implementing the changes. The upgrade is a complete rethink about how the motor itself works and is independant of the plinth chosen. A good comparison would be a before and after upgrade in the same plinth. It would be informative, for example, if this test was in a Dobbins based TT, your reference. Further the upgrade takes considerable time to settle. Experience shows 3-4 months until it reaches its peak. I will be launching a web site in the new year to explain in more detail. Many thanks. |
Kudos to Albert and others for generously sharing their knowledge with us. Albert is on the money with product improvement. I think in the 70's cost was no object , but since then knowledge shared ( internet ), new materials and the lower cost and portability ( no pun intended ) of CNC machines means that the opportunity is ripe for re-engineering improvements at relatively modest costs. Conversely we are in the age of mediocrity, convenience & cost cuts and some things are worse and were better built back then. Many materials due to shortages of trace elements and health & safety police have declined in quality. |
Albert, I apologize. I'm not saying that the performance was the same before and after the mods. I'm saying that the mklll with Krebs mods and the Dobbins style direct mount produce similar results. Yes I had issues with rubbing on the chassis and even sent the table and platter back to Bill after the mods. He ran it out of the plinth for two weeks without issue. When I got it back I was more careful putting it back into the plinth to make sure it sat flat and not over tightening anything. I now believe the chassis was torqued or slightly twisted when the rubbing was occurring. It now run very quietly rivaling the direct mount in silence. To me this is a question of eliminating noted or perceived performance issues with the original table(direct mount) or mitigating these issues with modifications, band-aides if you will. In my experience the band-aides are quite effective. I think it makes sense because both methods address the same issues. I do agree that ANY rubbing or friction completely eliminates the benefit of the modifications which is why I went to such lengths to figure out the problem. Kudos to Bill for going the extra mile to address that. I don't want to offend or argue with anyone. I've worked now with all three major plinth makers to good end. No single product has been perfect in every way but all work very well with tweaking. That's the nature of these vintage machines. The headache of getting them maximized is rewarded in the end. It's been a long journey for me but I finally seem to have reached a satisfying end point. |
Dear Sonofjim, Thank you for your detailed response. I am treading on "little cat feet", but I have come to understand that a Krebs-modded Mk3 in a Dobbins plinth would not be too much of a good thing. Mr. Krebs was kind enough to send me some photos of his personal Mk3, and it is sitting in a Dobbins-type set-up, i.e., the motor is taken out of its chassis and directly mounted into his plinth. Likewise, I would guess that a Krebs-modded Mk3 in a Porter plinth is pretty fantastic. But I had no intention of starting a controversy about after-market plinths. IMO, the difference between now and 25 years ago is mainly the zeal with which those of us in the here and now are approaching the art of playing a record. There was not much of a market for such craziness back then, except the tiny niche occupied by Merrill and a few others. Suspended tables with flimsy plinths, a la Linn, were also more in vogue back then. Fashions change with time. Remember the Woody Allen movie "Sleeper", where he wakes up after 200 years to find that steak and ice cream sundaes are health foods? |
For the same reason Technics did not know to do the Krebs mods which raise speed stability and improve transparency and dynamics. Albert, When Technics made their "mods" from Sp-10MK2 to Sp-10MK3 we see a clear improvement. This improvement reflected in the measurements of the Starting torque, Speed fluctuation, Wow and flutter, Rumble. Can we see some measurements before and after the Krebs mods? There are precious few products manufactured 25 years ago that cannot in some way be improved through modern materials and technology that simply was not available back then. The previous question applies to the modern materials too. Can we compare them with detailed measurements of the old anti-resonance materials - Kenwood Anti-Resonance Compression Base (ARCB), Sony Bulk Molding Compound (SBMC),Technics non-resonance compound (TNRC)? The SP10 mk3 also has TNRC loaded in its chassis (you know the TNRC is not a "glass" ;-) Just this way (loading TNRC in the lower base), Technics have managed to bring down the Rumble from -86dB (MK2A) to -92dB (MK3). |
Lbelchev, I would guess that the Mk2 and Mk3 are just so completely different that it was just fortuitous fall-out that resulted in the Mk3 having lower rumble. Moreover, somewhere around that time, the method for measuring TT rumble was changed such that the newer numbers were all about 3 db better than before. Hence the Pioneer P3 vs the P3a; the P3a has better/lower rumble specs, but the two tables were measured differently, and I am not sure there is any structural difference at all between them to account for that difference, save for the method used to measure rumble. (Of course, I could be wrong.) |
I would guess that the Mk2 and Mk3 are just so completely different that it was just fortuitous fall-out that resulted in the Mk3 having lower rumble. Lewm, Out of question the Mk2 and Mk3 are completely different. Some of the differences are due to the different materials - respectively different technical data. This is from Technics SP-10MK3 brochure: "Also contributing to lower noise is the sophisticated cabinet construction featuring diecast zinc, diecast aluminum, and Technics original acoustic damping material TNRC (Technics Non- Resonant Compound) in the lower base. - 92 dB rumble means real silence; it's a difference you can hear from the moment you lower a stylus into the grooves." :-) Moreover, somewhere around that time, the method for measuring TT rumble was changed such that the newer numbers were all about 3 db better than before. Yes, This is the reason that I indicate the SP-10 mk2A rumble -86dB (IEC 98A) and the SP-10 mk3 rumble -92dB (IEC 98A). The SP-10 mk2 have different method for measuring -73dB (DIN 45539B). |
Lbelchev, When they wrote "sophisticated cabinet construction", it sounds like they were talking about their plinth, which I believe was supplied as an accessory to the Mk3. But is it possible, or do you think, they were referring to the chassis proper of the Mk3? If the latter, very interesting to me. |
Technics SP-10 series plinths: From what I've been able to find, Technics offered as many as five separate plinths (bases) for the various SP-10 motor units. The one SP-10 I've seen (not quartz locked and no outboard PS) had a traditional wood box frame plinth. Quite lightweight and I don't recall seeing a model number. The SH-10B3 was a 12 kg layered combination of Obsidian, rubber, and wood and offered for the SP-10 Mk II motor unit. The Vintage Technics site lists a SH-10B4 at 5.2 kg and a lower price. I've not seen any other reference to it. The SH-10B5 was 19 kg and all Obsidian. It was introduced along with the SP-10 Mk 3 motor unit. Technics engineers obviously felt a more massive unit was needed for the increased torque motor. The last one offered that I found info for was the SH-10B7. It was also all Obsidian but weight was listed at 17.5 kg. I've wondered why this was slightly less than the previous model? This plinth was offered during latter production of the SP-10 Mk 3 and Mk 2A. The dates for these plinths ranged from the mid-70s to early 80s. Obviously Technics engineers were attempting to make improvements through materials and mass as they revised plinth design. But that is not to say it is what would be designed today with 30 more years of engineering knowledge and material choices. If there was a change with the SP-10 Mk 3 motor unit frame (or chassis as Lew calls it) I would be interested to see a reference to that. I've never see a Mk 3 but own a Mk 2A. |
Tim, the Mk3 "chassis", as you know, does not contain any onboard circuitry. It is merely a cradle for the motor and a mount for the on-off switch and the strobe. Ergo, the bit that hangs down below the square escutcheon (the "dog's balls", in Dover's parlance) is circular in aspect when viewed from below, and its diameter tapers toward the bottom. IOW, it encases the motor assembly, only. Thus it does not have a potentially resonant cavity (or at least the cavity is very much smaller and confined), compared to the Mk2 chassis. You cannot put a Mk2 into a Mk3 plinth, as the former would not fit, not only a square peg into a round hole, but also a square with a side slightly larger than the major diameter of the Mk3 plinth circle. |
Hi Lew, Now I'm confused. What I'm asking about is the cast metal frame that surrounds the platter, and in the case for the Mk 2 and Mk 2A provides support for circuit board attachment from underneath. Since I've never seen a Mk 3 except in photos I'm not sure about it. But from the top it appears identical to the Mk 2 and Mk 2A. This is what I understood you to mean by chassis. The Vintage Technics site, which of course is not infallible, states the SH-10B7 plinth was intended for both the Mk 3 and Mk 2A mounting. The opening in that plinth is indeed not round. See this from Vinyl Engine - http://www.vinylengine.com/library/technics/sh-10b7-obsidian-plinth.shtml What I'd like to know is if the cast metal frame for the Mk 3 is different from the Mk 2A? That is, were additional vibration damping methods applied? |
"I will leave it to Audiogon members to decide who copied what. Take a look at ads and dates." I believe there may be some misunderstanding here, allow me to clarify. People often serve as inspiration but rarely can single individuals claim to be the emperor of all. This case bears no exception, as you yourself designed a plinth which was obviously inspired by the exterior lines and angles incorporated into a much older existing design developed originally by Technics for the very SP10Mk2 and Mk3 models that you and I, amongst many others, so passionately continue to covet. I do not wish to, nor has it ever been my goal to invalidate or diminish your own efforts (publicly or privately), however, since you continue attempting to stigmatize my own design efforts on public forums, I will then rightfully respond. True, you may have been the primary source responsible for bringing the Technics SP10Mk3 back into the community spotlight is not the contention and I believe I have already acknowledged this. The timing aspect of offering an updated revised version of the SH-10B3 style plinth, apparently is. Yes, indeed your plinth baring this form did reach the marketplace first. However, neither you nor any member here can claim that another SH-10B3 shaped plinth was not also in the developmental stages by Artisan Fidelity during this period of time. My design, inspired by the original factory design and thereby "your" design is quite different however (as mentioned previously), in its internal constraining layers, materials and implementation of these as a whole. The balance in terms of presentation is quite different, this much I can assure you, as I have spent enough time personally listening to your plinths sent in for repair to know first hand. People learn from other people and that is the beauty of the game, this does not have to be a competition. In all fairness and for the record, you took some of my ideas and I took some of yours and we learned from each other. For those members not aware, over the course of the past year and a half, we have had several A. Porter plinths in for extensive repair as a result of the Ebony plank wrap severely splitting apart along all sides. It was not long after this, that A. Porter began building his plinths with much thicker plank wrap, obviously as a preventative measure against cracking, this same practice has been employed and advertised by Artisan Fidelity from the beginning, then later copied. I see another more recent practice of yours, the advent of chassis refinishing/coating, platter refurbishment and even more comprehensive restoration services which have been employed, again these such services have been offered by Artisan Fidelity from the start. These will be my final comments regarding this issue on this thread. I would ask though that you please refrain from continuing to chastise our products when in reality we continue to respectively move in different design directions. I think its time to bury the hatchet. |
Bury the hatchet would be to drop the subject since my last reply was short. Additional short answer is my plinth has no relation to the stock Technics plinth other than the radius around the perimeter. Your's on the other hand copied our iron block and rod, recessed chassis, arm board design, rubber grommet and plate outlet for umbilical cable, metal interior plate sandwich to Panzerholz and pretty much all interior and exterior dimensions. |
Dear Tim, I think my original response does address what I think is your question. From the top side, the Mk2 and Mk3 "chassis'" are indistinguishable, as you suggest. What I was describing is that the part you don't see when the two are installed in any plinth is very different from one to the other. The SH10B7 plinth may indeed work with both units, but if you use the Mk3 in an SH10B7, there will either be empty space where the circular shape of the Mk3 motor housing does not conform to the square shape of the Mk2, OR there may have been a factory supplied insert that makes the SH10B7 fit the Mk3 snugly. Since Albert is among us, I need not speak for him, but I believe his plinths made for Mk2 can be adapted to Mk3 by adding some sort of wood inserts, or so it seems from one photo I once saw. Perhaps AP will comment. |
Tim, I should have added that because of the drastic difference in shapes, a plinth custom-made for a Mk3 would not fit the submergible portion of a Mk2 chassis. It's a square peg into a round hole, where the side of the square is at least the same as the diameter of the hole, and maybe bigger. Vice-versa mismatch would "work", as described. |
To clarify the design evolution on the Porterhouse plinths, I will start from the beginning. In August of 2007 I built the first plinth to Albert's specifications from Baltic birch covered in wenge. It can be seen here: http://farm9.staticflickr.com/8204/8283876129_eda99c9574.jpg As you can see, the corners are chamfered and the chamfer along the top edge resulted in a facet on the corners. Albert asked me how I could eliminate that facet and improve the appearance of the next iteration and I told him that by rounding the corners instead of chamfering them there would be a smoother transition. In December of that year I built the first of the Panzerholz plinths from material I had left over from another job. They were for the Garrard 301 and the Thorens 124. Albert was intrigued by these designs and asked me to incorporate Panzerholz in the next SP-10 plinth along with other improvements in design such as eliminating the facet, enlarging the armboard for more versatility, and my own idea of chamfering the bottom edge as well as the top to eliminate the chunky appearance. At this time I hadn't seen a Technics obsidian plinth since the seventies (which by the way is molded from crushed obsidian in a polymer matrix, and not carved from solid obsidian) so from my point of view the resemblance between the two plinths is coincidental. The improved plinth can be seen here: http://farm9.staticflickr.com/8500/8284935462_ef0d60ecc3.jpg There was a significant improvement in background blackness with the Panzerholz plinth so I began building simple plinths for our friends. One of our group suggest that we produce these plinths for a broader market but I wasn't that keen on the idea. However interest began to build on Audiogon and Albert sold a few of these simpler models there. There wasn't a whole lot of money to be made on these so Albert asked me to develop a two arm version of his ebony plinth so as to move up-market. He shelled out the $7500 for the Panzerholz after my supply had been exhausted and we began building this model on a limited basis: http://farm9.staticflickr.com/8076/8283876371_c1d095f9b2.jpg Shortly thereafter some cheaper clones appeared on the market which mimicked the exterior appearance but of cheap construction and they sold in the $750 price range. Later Artisan Fidelity came out with a higher end version which appears to me a cold copy of the Porterhouse design, although of different construction technique: http://farm9.staticflickr.com/8068/8284935288_9b85c6d9ff.jpg I can't say that the whole business hasn't been without problems due the difficulty in working with Panzerholz and its tendency to expand and contract a great deal with changes in humidity, not to mention similar problems in consistency with ebony and its own problems with movement and subsequent cracking. To this day I feel badly about the problems that arose with Kent's plinths and in the end I have to put it down to improperly dried ebony slabs, since none of the other ebony plinths experienced splitting to that degree. I hope I have answered most of the questions anyone may have had about the Porterhouse plinth and its evolution. John |
Lew, thanks for your clarifications. I think I should have approached my question a little differently. Since I have a SP-10 Mk2A I'd be interested to hear from anyone who modified their Mk 2 chassis. Since the number of Mk 2 and 2A (same chassis I'm sure) so greatly exceeded the production of Mk 3 motors it seems reasonable there might be more interest in Mk 2 and 2A upgrades. I'm not interested in going to the extent of eliminating the chassis and mounting the platter/motor directly to a plinth but if performance upgrades (reduced resonance) can be achieved by chassis modifications (damping) I would like to hear about specific recommendations. Thanks. |
12-18-12: Lewm A friend who listens with us occasionally is the first person getting Krebs MK2 mods, at least on this side of the world. His MK2 was still at Bill's two weeks ago but hopefully it's near completion. My friend (Ken) also has a Krebs Technics MK3 so he's clearly the person to answer this question. He has an ultimate system, very high resolution and pro tape machines that serve as baseline for sound. Depending on his report I may invite myself back to his home so I can hear for myself. |
Dear Albert, You wrote, "My friend (Ken) also has a Krebs Technics MK3 so he's clearly the person to answer this question. He has an ultimate system, very high resolution and pro tape machines that serve as baseline for sound." I am a bit confused. First of all, what is the question that Ken might answer? Second, I understand that you own and have been listening to a Krebs-modded Mk3. So why would you need to get over to Ken's house to hear a Krebs-Mk3? Thanks. |
You ask this question: 12-18-12: Lewm My reply was in response to that. Is that not what your question concerned or do you not have interest in performance differences on the more affordable MK2 mod? I spoke to Ken yesterday and he has his modified MK2 back from Bill's place. With the holidays it's not likely I can get over anytime soon. |
Lewm, Nope, not a dunce at all, these threads get so convoluted it becomes difficult to follow. I hope the MK2 mod is wonderful if for no other reason than it's an affordable upgrade on a turntable that's reasonably easy to find. The days of clean Technics MK2s for $800.00 are long gone, but even at current prices they're cheap. Especially compared to something like your Kenwood or MK3. |
I am "Ken" referred to above. I finally have my Krebs-modified Technics SP10 MK2A up and running and have posted comments over on Albert Porter's system thread about this table generally and also in comparison to the Technics SP10 MK3. Apologies for taking so long to post these comments, but water leak repairs in the stereo room caused the delays. |
Hi Lewm - My system is: Focal speakers and subwoofers; Boulder electronics, Tara cables throughout (for phono cables, in addition to Tara, Graham IC70 and Huffman). For turntables, Technics SP 10 MK3 and MK2a and Denon DP 80 direct drives, several restored Thorens TD 124s (with aftermarket platters and bearings for idlers), and Basis Debut Signature for belt drive. I use many different arms from current to vintage SMEs (9" through 12"), Graham Phantoms, Vector, vintage Technics EPA 250, and many different MC and MM cartridges. Although I really enjoy the equipment, music is my passion and that primarily classical. My reference for sound quality is live music, after spending many, many evenings in concert/opera halls mostly in my younger days. |
