Technics SP-10 Tonearm Pod instead of Plinth/Base

Fehhhh on perspex. Bad idea, IMO. I know that Clearaudio uses perspex for everything, but they are making belt drive tables. That's a different kettle of fish.

I make slate plinths, under the OMA name, so obviously I am not unbiased. And I HAVE listened to an SP10 with no plinth. Which is why it strikes me as rather absurd to go that route. Same with people who like a skeletal or box plinth with decks like the Garrards. I started making slate plinths first for my own SP10, and at that time you virtually could not mention that you used that deck, as it was so out of fashion.

In any event, I found the difference between using slate, and the wooden plinths I had made, or one of the Obsidian stock plinths which I also own, was so impressive that I began making slate plinths for other decks as well.

Running an SP10 without a proper plinth, and with a separate armboard, is a very bad idea.

Someone has suggested perspex with a layer of another material, like aluminum or wood. Not sure about perspex- reviews of turntables plinthed with the material don't read well.

Hi Lewm,
No, Corian. I read up on that- it's really some sort of polymer (Ie plastic). I also saw that people had tried it and it made a poor plinth- plastic is very unsuitable.
Think terrazzo. That's a sort of fancy concrete with pieces of marble through it- looks great! Other aggregates might be good too.

You mean Corian? The scuttlebutt on Corian is that it does not sound so good as a plinth. This is only word of mouth information. I think Jean Nantais is one person who tried Corian as did some others with Lenco tts. Don't give up on concrete, IMO. Maybe you can make a mold and cast a piece with a square opening for the SP10 chassis.

Hi Lewm,
That is interesting info on the L07D. As for my budget concrete plinth- I suppose I would have to make sure that the 'slab' I buy is able to be cut without crumbling. I regularly see workmen cutting driveways and the like with a water protected circular saw arrangement. The tonearm hole would be easy, the space for the SP10 could be tricky.
What about a material like they use in kitchen benchtops? Nice colours too!

Concrete might be excellent. I recently saw a Kenwood L07D. It's plinth is made in part of a very dense particulate material, much like concrete. (The plinth is further damped by metal and wood layers.) By all accounts, the L07D is VERY quiet, so I assume the plinth "works". But this makes shipping of an L07D a nightmare, because that concrete-like stuff may crumble if it receives a blunt force blow. I would think also it might be difficult to make a precision fit with concrete, because does it not shrink while drying? But in principle, concrete would be an interesting choice and would probably work well. I see that you propose to start with pre-formed slabs of concrete. Can it be "worked" to accept the SP10 without crumbling? Anyway, it's a cheap experiment.

OK, I'm going out-of-the-square.
What about a thick slab of concrete with holes cut-out for the SP-10 and a tonearm? Terrazo? Other aggregates? Does anyone know the sonic properties of the afore mentioned options?
What about three of four cement tiles, with holes cut, and then bonded together?

I don't have any idea why it might be so, but I have had negative reports on marble as a material for plinths. You can say it rings when you tap it, as does granite, but I have never understood how/why that should be the determining factor. I would stick with slate or wood. The Japanese have virtually no access to slate, which is why some of them may use marble, but I must say also that I have never seen a marble plinth in any of my several trips to Japan, during which I haunt audio stores.

Dear Dsa: I try and I have two heavy ( 40-50 kg ) lovely Marble ( green. ) and Onyx ( beige. ) plinths that I used with my Denon's ( DP-80/75. ).

Looks great but I can't say in this precise moment how good against my no plinth approach.

Regards and enjoy the music,
Raul.

I forgot to mention my third option for a plinth- Marble. The Japanese seem to think that this is the best material for a direct-drive TT plinth. Slate is another, but marble is easier to come by and preferred by many.
Has anyone tried a marble plinth?

This is yet another of those "to each his own" audio discussions. We can be comfortable knowing we are all in the right. Have fun. If any one of us besides Raul tries it both ways, please report back on your preference.

DSA, as for the layered plinth I made that my first choice of options that are out there. I think solving a problem seems to always create another one. With that said I have thus far made audio choices based on what someone had to say about the particular component and how it would work with the rest of my system. Now I have made a choice to test and see how it works and if I like it I will continue to use it or if I don't like it then I will take a look at other options. I urge you to do it your way just to see if it works for you.
Thanks

Thanks everyone. For me, a lack of funds is the mother of invention, so that's why, at least in part, I'm thinking of Raul's clever approach.

I've always been a little circumspect when it comes to wood and turntables. I believe that its use transforms the turntable into a musical instrument (I also consider that sprung suspensions add to the euphonic mix). While all plinth designs have this effect, the goal (for me) should be neutrality. The more 'stuff' attached to the device that is extracting the micro signal from the groove, the more chance for colouration.

Lewm: Good points to consider. In place of the AT pneumatic feet of Raul's set-up, I was thinking of some of those fantastic feet from Herbie's Audio Lab. They would perform the isolation task very well and secure the TT to prevent dancing across the room... The company also make a great matt that is perfect for the SP-10. As for the pod, checkout this pod with adjustable feet, layering, damping and (brass?) weight:

http://www.turntables.lt/gallery/tonearmturret/norm_04859_2009-04-04.jpg

Rnadelman: Ah, the layered approach. If I had to go with a plinth, I think the plywood/aluminum woud be the best sonically. There is someone here (In OZ) who makes them. Do you think that they do a better job than wood of draining unwanted resonances?

Jsadurni: See the link above- is that the kind of 'pod' you made? Would you say that your setup keeps the speed and bass reproduction while extracting the upper mid and treble with air/space/soundstage depth?

Raul: It seems that Jsadurni is getting great results from the non-plinth + tonearm pod approach. I agree- I can always try the setup first. The feet I can use later with a plinth if the pod idea doesn't work.

Keep the idea coming, thanks everyone!

About the Theory of Mechanical Linkage of the TT chassis against the tonearm, in my point of view, less vibrations are better than "joint" vibrations. Now to theorize here seems a bit ridiculous but any way I will give it a go: To have a synchronized vibration could work in order to lets say minimize the sum of vibrations, but this would mean that both the Tonearm and the TT are at the crest of the vibration at a given moment and at the valley, in complete synchronization, if one is at the valley and the other at the crest then it is better to have them Isolated, in a separate Pod. Now, in music we know vibrations are in a lot of frequencies, not only at one, so to have a synchronized movement that would annul the vibrations in all frequencies seems a bit complicated.

This would be theorizing on a result I found in practice, I dont know how valid that could be since we could also theorize on the contrary.

Practically I like it better.

Raul has a point; I have never heard an SP10 sans plinth. Really, there are two issues here: (1) plinth vs no plinth, and (2) outboard arm pod vs mechanical linkage of the tonearm mount to the tt chassis. I feel more strongly on the latter subject (pro-linkage) than on the former. It would be simple to take a piece of plywood to form a skirt fastened to the underside of an SP10, with enough area beyond the boundary of the chassis to allow for mounting of a tonearm. Then you could put the chassis on feet like Raul has done, and you would have no-plinth but with linkage. I may try that. But you guys can keep your outboard arm pod. One other issue that comes up whenever Raul gets into this subject; who else has a set of those Audio Technica feet? Since they are rare, what else would do as well? I could imagine that the no-plinth SP10 might have a nice open sound quality, or it might not.

Dear Dsa: The plinth or not plinth subject is so controversial because no one of those plinth advocates guys never test/try the SP-10 non plinth alternative ( at least I never read that any one of them tested. ), so they don't know for sure which approach achieve better quality performance.

Well, I did and that's why I support the non plinth in the SP-10 and with a tonearm separate tonearm pod.
How anyone can talk on the subject if never has the opportunity to hear it?

Dsa, if you care mainly about quality performance more than how it looks my advise is that you try it ( it is inexpensive to do it. ) before pay a lot of money for the plinth solution and then decide about.

I'm not against any SP-10 alternative on the subject, my clear and precise position here is: how to achieve the best quality performance, that's all.

Regards and enjoy the music,
raul.

I have such a setup, I got an Sp10, I took out the plinth, given a cheap one, but it was like taking the bell out and leaving only the little metal ball inside it.
I made a pod for the tone arm with 3 different metals and it is pretty heavy, trust me it wont move. The Sp10 is sitting on its own with no plinth at all, I have cones holding it from the original chassis, we actually discussed even taking the chassis off.
The improvement was impressive, in micro-level detail and air around the instruments.
Isolation is very important and the cones that support the SP10 can change the tone of the setup, for a tubed Phono preamp I like solid steel cones, for SS I use the famous Audio Technica Support Isolators with metal cones. Actually my favorite sound came from a combination of cones.

The Pod base stands on cones also, that improved the sound a lot also.

I dont want to rub the people with plinths the wrong way, this is my private setup and I like it, my system consists of triamplified 5 way horns.

Check out theanalogdept.com/stefano_bertoncello setup, he uses a Garrard with a Pod also.

Guys, If I am wrong about Raul's rig, I stand corrected. It means that I have been under the wrong impression for several months. In fact I thought Raul agreed with me when in other places I had stated my case against having separate arm pods. Nandric, I know Kuzma does do it that way in their top line product, so evidently Mr Kuzma does not agree with me that it is a bad idea. He is probably smarter than me, too. But there is a difference between a minimum plinth SP10 and the Kuzma table you own in that your table AND your outboard arm pod have enormous high mass. Also your table does not potentially suffer from being spun on its own axis by its motor (due to Newton's 3rd Law of Motion), as could happen with an SP10 chassis that is just sitting on a set of Audio Technica feet, a la Raul. (I have seen this happen with my own SP10; it does not actually spin around of course, but it twists at start up, if you just sit the chassis on a table. Eventually after several start-ups, it will move across the table top. This would tend to screw up geometry.) I also would point out that there are other smart guys (turntable designers and builders) who agree with my opinion on this matter. Eventually, Raul will see this thread and trash me. In fact, if he likes his SP10 set-up, it probably sounds good. This is all meant in good fun.

Dsa, Jim is making the layered plywood plinth with aluminum for me at this time.

Hi Dsa, I am very reluctant to contradict Lewm but the so
called 'theoretical arguments'(aka 'scientific') are regulary used in our forum as long as they don't contradict
with our preferences. Well I have an 'armbase' next to my Kuzma S.R. and I prefer this combo (Reed L2A+Reed base+ Phase Tech P3) above Triplanar VII+ Benz Ruby 3 'on' the Kuzma.

Regards,

Thanks All!
Lewn- I'm pretty sure from reading the blogs that Raul's armboard is separate from the turntable- ie not touching. However, I do see your point of keeping an even playing field by having the tonearm and the platter sharing the same plane. That being said... some brands of TT have a separate pod for the motor when the platter is driven by a belt. I had this idea in mind as I wondered of a pod for the tonearm. Maintaining geometry is still a vexing question.

Jax2- The Porter plinth is beautiful, yes. It also looks one step away from being gilded with gold... ie very expensive as you suggest.

Rnadelman- I've googled Mr Campbell and found a couple of pics of what looks like a very nice plinth. I'll drop him a line.

The other plinth option is a layered plywood plinth with the odd layer of lead or aluminum. A better option than solid/heavy/dense wood plinth?

Hi DSA, Jim Campbell makes a plinth, I have only seen pictures however he is making one for me. He can be contacted at JEC@AFO.net. I think I saw his ad on Audiogon
You might do a search a see.

The plinth Albert Porter had a hand in developing for the SP10 is gorgeous. He may have sold through all of them, but you can always give him a try. I'm not sure if he's having more made. They ain't cheap, as you can guess from the pics....but, up close and personal, they do look and feel very much like you get what your pay for.

I am not sure that your description of Raul's set-up is correct. I thought he had mounted the tonearm on a short skirt of plywood that is also fastened around the tt chassis. In any case, that would be my preference, if I were to go with the ultra-light approach. If you isolate the tonearm from the vibrations of the chassis, then the chassis/platter/LP will vibrate while the tonearm/cartridge stands still. This in theory could maximize badness. Don't you want the tonearm/cartridge to be on the same roller coaster with the bearing/platter? The problems of maintaining geometry only add to the mess, IMO. I saw a nice plinth on eBay for a bit less than $500 from somewhere in the US or Europe. I saw a cheaper one from somewhere else in the world that I did not like nearly as much.