The Incredible New Technics SP-10R Thread

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I know of at least 3 members here who have one. There is a whole new world out there with plinths and modifications just waiting !

Many will know me from the SP-10 thread where I attempt to help people get old ones working. This is getting more difficult (but still possible) over time.

And yes I keep them in stock and sell them.

Click here Technics SP-10R for recent reviews, manuals etc

Here in Europe they come in massive wooden crates with the SL-1000R weighing 85Kkg !

I am hoping a member here "Bon" will tell us of his adventures with plinths later ?
 
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Time to kick-start this thread. I will break up my comments into a series of smaller posts. I took possession of a Technics SP10R in August, courtesy of Dave Cawley. (Thanks for the hospitality of my brief visit, Dave). Back in Sydney, I got down to the construction of a plinth for the mighty machine. The HFN review of the SL1000R raised concerns with the performance of the Technics plinth.
http://www.soundhifi.com/images/HiFi News SL-1000R review.pdf
I have used the mkII for two decades, in custom plinths of my own design and construction. I have experienced first hand the effect that various plinth materials and construction methods can have on sound quality. For non-suspended high torque turntables such as the SP10 mkII and SP10R, attention to the fundamentals of mass, stiffness and damping of the plinth makes a noticeable difference to the sound quality. A direct-drive turntable like the SP10R has a constantly acting servomechanism that attempts to reduce speed fluctuations to an imperceptible level. A counter torque is experienced by the mass of the chassis plus plinth. A good plinth controls spurious motion due to counter torque by mass and damping.
 
A properly damped plinth dissipates the reaction torque and main bearing noise, minimising the influence on the plinth/tonearm interface. Over many years, I have tried many plinth materials and damping methods. My finding is that starting with a material with superior internal damping works best. Applying damping layers to stiff substrates did not get the results I wanted. A while ago I settled on isophthalic polyester resin/bentonite compound cast into a mold, as promoted by a DIY Audio member Cat Squirrel.
damping factor values - audio qualia
He has compiled damping factor test results of standard samples of many candidate plinth materials. Panzerholz is the best but the resin/bentonite is close.
Panzerholz is very expensive and hard to machine with typical DIY facilities, and was rejected. Using resin/bentonite required a quite lengthy learning process. Firstly the optimal formulation of resin+catalyst+bentonite. Then the mixing and pouring technique took time to get right. Then the process of mold making, choice of mold inserts, extraction methods for the inserts, curing time, testing mold release compounds, repair of molding defects and prep for painting, base coats application, clear coats and buffing etc.
 
The overriding principle is to use the damping properties of the resin/bentonite plinth material as a sink to damp residual vibrations from motor reaction forces and the main bearing. Another issue arises when the turntable is used with an isolation platform, such as an air table, active table or negative stiffness platform. These all decouple the supported mass from external structural vibrations experienced by the stand and support. Unfortunately decoupling works both ways. Turntable induced vibrations cannot be drained to the stand and have nowhere else to go but into whatever is in contact with the chassis. A plinth with excellent damping is a good start.
 
There are a number of things I don’t like about the SL1000R plinth arrangement. The SP10R plus arm boards drop into the SL1000R plinth, like a skirt. It is open at the bottom, with the SP10R secured by nine 5mm bolts around the perimeter. The open base compromises torsional stiffness of the plinth, in my opinion. The bulk molding compound base is an extensional damping layer to control the aluminium top plate. Aluminium has a terrible damping factor compared to the best materials available. Moreover, my experience is that extensional damping layers are outperformed by materials with high internal damping. Secondly, the tonearm mounting boards are cantilevered from the edges of the SP10R chassis. I prefer a solid a mounting of the tone-arm+plinth+chassis. My ideal tone-arm mounting is a drilled plinth top plate. The chassis-plinth-tonearm connection is then as rigid as possible and better able to preserve the relative stylus-groove motion. As Yoda would say, “no tone-arm board is as good as no tone-arm board”. Of course, this is inconvenient if you want to change tonearms! My compromise is a substantial cast tonearm board similar to the bulk plinth material and rigidly connected around its full perimeter.
 
Since I have a number of excellent tonearms and cartridges, I wanted to make maximum use of the SP10R by mounting multiple tonearms. The Technics tonearms for the SL1000 are typically 10” and the chassis of the SP10R is just able to be used with a 9” tonearm like my SME IV in the standard position. The SP10R platter is off-centre to the square chassis, so when using a 12” tonearm in the standard position, there is a big space of plinth between the tonearm mount and the chassis. This unnecessary expanse of plinth material increases the already high overall mass by upwards of 5 kg. I chose to mount the SME V12 at the front right and rotate the plinth anti-clockwise by 90 degrees. Because of the platter off-set, the V12 is mounted much closer to the chassis in this position with much less wasted plinth material, keeping the overall mass down. The SME IV is now located at the rear left. Because of the peculiarities of the SME anti-skate, their arms are always at an angle to the chassis. My mounting positioning of the V12 puts its headshell above the speed selector switch. This just means I change speed, if necessary, after positioning the tonearm over the lead-in groove. It has caused me no concerns so far. Most other tonearms are designed to be parked in the straight ahead position, so this arrangement should cause no concern. Also, the styling of the SP10R labelling is very discreet and the rotated lettering is hardly noticeable. Others may disagree. A primary requirement was a compact plinth. Even so, the plinth mass is 35 kg. The overall weight of the plinth+SP10R+tonearms+stainless steel/carbon fibre mat+peripheral ring+record weight, is 67 kg.
 

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When measuring the motor drive and how much current is applied during nominal running conditions, start and stop, and when a very minor disturbance occur, you'll find the reaction torque theory doesn't hold water.
I put the plinth + SP10R (no tonearms) on a lazy susan with a low friction ball-race track. When switching on the motor, the whole > 65 kg rig rotated in the opposite direction to the platter greater than 90 degrees due to reaction torque. There same occurs on switch off in the opposite direction. It was essentially friction and the resistance of the power supply lead than stopped the motion. Of course when close to nominal speed the correction torque variation is small, but is it negligible? I haven't measured it. Try the lazy susan trick yourself. It is fascinating.
 
Here are some photos.
One curious thing about the SP10R, is the use of 4 extra fixing bolts to the 5 of the mkII, for a total of 9. I wondered why so many? I can only guess that Technics identified resonance nodal points that they wanted to control. When I examined the underside, I found that it was surprisingly quite resonant at various points. Especially the thin cover plate underneath the switches and buttons. The additional fixing points are not in this area though.
 

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Here are some photos.
The quality of the components justified a superior support, and this is supplied by a MinusK 150 BM-8 negative stiffness platform. I was very surprised at the difference it made. The noise floor dropped noticeably. I considered that my previous plinth isolation feet were pretty good but the MinusK is in another league. The immediate first impression was that everything was louder. I had to turn my pre-amp down a couple of notches to get my usual comfortable listening level. The music is now sitting above a reduced level of grunge. I am confident that this is the MinusK contribution, since I had been listening to the SP10R on conventional isolation feet for a number of weeks before the MinusK arrived. I am wary of giving my subjective opinion, since everyone will hear differently. Overall, I would summarise the combination sound as smoothness with enhanced detail.
 

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Time for an update from me. The price was widely speculated as being higher than it actually is. From Japan to Europe and onto the USA, bearing in mind local taxes and exchange rates, is almost exactly the same everywhere. There are some countries where they are not available and I can help there. The current prices are :-

SP-10R UK £7,995.00 including 20% sales tax (£6,662.50 less sales tax) USA $9,995.00

SL-1000R UK £13,995.00 including UK sales tax (£11,662.50 less sales tax) USA $18,000.00

I am disappointed to report that all of my 3 plinth projects have failed. They were either going to cost too much or not meet our desires. We are now on a 4th iteration ! However as shown in the first post the SP-10R can be used without a plinth at all.

There have been comments about the SL-1000R plinth and without listening to one I felt the same, especially about the arm supplied. However I have a SL-1000R on my own system now with a Glanz MH-104S, Glanz Stainless Steel armboard and a Miyajima Madake. It is stunning, no feedback in any direction and it easily passes the knuckle test !

I was at the UK pre-launch in November 2017 where a PowerPoint presentation went on endlessly about many things, including the SL-1000R plinth which I took with a pinch of salt. But as it turns out they were right. The plinth against all odds and perceived wisdom is very, very good. There is no doubt that my up-coming new one and Bon's is better and of course recommended. But for out of the box WAF, the SL-1000R is great.

Measurements suggest very little energy is applied to the motor whilst it is running. Of course with a low compliance cartridge and a high mass arm, the plinth needs to dissipate that energy without feeding back into the platter. The reviewer of the HiFi News article said to me in person, how quiet the lead-in groves were on known records, I have encountered the same and turned up the volume expecting a given level, but had to turn it back down again. This isn't of course louder, just that the surface noise appears to be quieter. More later (probably) !
Oh, and as usual YMMV..................
 
Hi Bon

Yes JP and I own and have heard both. They are different and there is no escaping that. Measurement wise there is nothing in it. Sound, well I'm not sure, the MK3 has a heaver platter and a bigger bearing and here expectation bias kicks in.

In essence there is no difference. The big thing is that the Mk3 is difficult to service and I believe only JP and I can do this. Mk3's are still about the same price as the new R.

In an ideal world you should have both. If that's not an option then the SP-10R is a no brainer.

Does that help ?

Dave