This is a project that's been on going since the days of my Lenco experiments. My Lenco project is posted as a virtual system here at Audiogon too.
My Technics SP10 MK2 in custom African Wenge plinth is posted in my main system and this Technics SP10 MK3 in Panzerholz and Ebony Plinth was completed November 20th, 2008.
More images to follow, including the Ebony custom platform it will rest on. The platform is 9 layer construction including a layer of Texas Instruments shield with active ground plane.
Kftool, aren't the vacuum clamp-down systems built so that there is a very thin cushion of 'vacuum' between the platter and the record (other than where the rubber lips meet the vinyl)? I have never used one but I have always assumed that from looking at them up close.
With all due respect from a guy that likes his records SUCKED down. Putting two metal plates together and expecting them to mate as if they are one is utopia. I tell Sue that her nooks fit my crannies, but we're both flexible where metal isn't.
If coupling the record to the platter is important, shouldn't it be necessary to treat the platter, mat, record as one. When a record is cut on a lathe it is SUCKED down to the massive platter so that the only vibrations that EXIST are those from the cutter head.
In playback, shouldn't we mimic the same conditions that existed when the record was cut?
The Neumann lathes used a direct drive motor to power the platter, in the same vein as the Technics and Denon tables; I think it was a Technics, if I'm wrong I'll hear about it.
Have you tried a coupling agent between the two metal plates on your SP 10 MK III ?
I just can't get over watching a record go around with vertical deflection. Vacuum, perimeter clamp ring, a cat riding the recording as it goes around, it seems that something is necessary. Maybe all I need is another cat
I forgot to ask what you're using between the copper Micro Seiki mat and the metal SP 10 platter. I have a micro mat I'd like to try but need something in between the two metal plates; felt, rubber or something.
a dear friend of mine was wiped out by the Madoff scandal. Now he is 77 and his future is very unclear. Trying to find work is bad enough now. I'm 66 and no takers, him at 77 has zero chance. With no family left he may wind up in a gov supported ALF. Sorry to be somewhat off topic here.
I have a room reserved at the Tucker Pavilion in Richmond for the mentally deficient. Your response will determine if I need to make a deposit!
Fritz the Cat, please reserve a room for me as well :^).
The vacuum hold down is a great idea, unfortunately the Technics does not have that feature. Then again, I owned a Versa Dynamics and two Basis Debut Gold tables that had vac hold down and the Technics is better than any of those.
Makes me wonder what the MK3 would sound like with vac.
Glad work is good for you, I and the rest of America are struggling to find enough work to keep bread (and Technics) on the table.
I'm sorry I missed you at the CES but my company ACTUALLY GOT AN ORDER! I had to wurk, weerk, wuerk, wuerc. work for a change; it's been so long that I'd forgotten how to spell it. My ticket was non refundable but I charged it off on the company as I have, had, a few customers in the area.
The Denon DN 308 table that I got from Peter at PBN audio is beautiful. He veneered the cabinet with rosewood and the job was stellar! Since he builds top dollar loudspeakers I expected nothing less than the best.
I look to you for advice regarding a mat. The factory mat is old and funky; we both know what that that means, especially at bedtime. I have a copper mat from a friend and an Oracle mat that I bought for my Thorens TD 124 many moons ago. With the original mat the sound is fabulous, even if it's not a belt drive, suck down platter.
Albert, I'm a firm believer in vacuum hold down on playback, as that's how the master is cut. I have a table with speed accuracy to the n'th degree but if the record has contact problems with the platter I might just buy that Table that spins the record in mid air, the Ronco MK III.
Next weekend our audio group is traveling to visit "The Record Cutter" in northern Va. to view three Neumann Lathes and cut a record from a source we each bring. I'll be looking at the vacuum connection to the platter that Neumann incorporated, a tube to a hollow center spindle. My thought is to ply a vacuum disc to the DN 308 platter and end up with the same result as Neumann designed in their last lathe.
I have a room reserved at the Tucker Pavilion in Richmond for the mentally deficient. Your response will determine if I need to make a deposit!
Kmccarty, I'll post results here once I see and hear the results. If I'm pleased I'll let everyone know and they can contact the guy for their own needs.
T_Bone, I ran across a web site that claims their aftermarket SP10 MK2 power supply is superior to the original, but I have not heard it.
I have my SP10 MK3 in the shop and should know in a few weeks what the expert I choose can do. I've ask him to rebuild the power supply completely, and tighten up the specs.
I think my memory is good enough to be able to relate here what the upgrade brings to the system. If in doubt, two other members of my group have stock original MK3 power supplies and we can do a shoot out.
I have not used the Micro Seiki mat for long enough to determine if it causes any of the problems you mention. Truth is, I have not determined if I prefer the Micro Seiki over the three or four other mats I own.
I finished the MK3 project, acquired two new phono cartridges, two new tonearm cables and upgraded my Aesthetix around the same time. I need a bit more time to figure it out but promise not to hold back the truth, whatever I find.
As for Slate, I like the Saskai system I saw at RMAF. I wish I had the cash to get one of those built for my MK3 and test it all.
I am curious about the Micro seiki mat you are using. Have you found any problems using it with respect to increased bearing noise, premature wear, stress on the motor due to increased weight? Also are you using a record clamp?
How thick is the aluminum plate you are using, and is it positioned in the center of the plinth?
What adhesive(s) are used to laminate the various layer of the plinth?
Thanks Albert and John. I just did a bit of digging and found this page detailing the acoustic impedance properties of a variety of metals (and indeed, cast iron looks like great bang for acoustic impedance buck). On other pages within the same site there is a discussion of acoustic impedance (use the search box at the top of the above link and search for "acoustic impedance") and a java applet. I have not been able to get it to work yet, but it looks worthwhile, especially because the applet is supposed to demonstrate that a change in acoustic impedance significantly affects how much acoustic energy is transmitted from material to material, which directly relates to what materials one wants to put together, and in what order, which is what plinth-builders are trying to solve for.
Acoustic impedance, when you break it down to its base parts, comes to be calculated as:
Acoustic Impedance = Density x SQRT(elastic constant/density)
which at first glance makes intuitive sense to me (as well as confirming what you noted above, that density is a major factor in the calculation)
I was told density is one of the prime descriptors of metals ability to absorb energy. Our first thought was Phosphorous Bronze or Tungsten but both were crazy expensive.
Here's a density scale in KG/m3 for various metals:
On page two of this document there is a list materials showing their specific damping capacity. Iron was chosen for Albert's plinth because manganese bronze was prohibitively expensive and the magnesium alloys weren't readily available. You could say that grey cast iron offers the most damping capacity per dollar.
I have used the Einstein phono stage for about two years and have very similar feelings to those which Albert expressed.
For those that don't know, Fred and I are good friends. We spoke on the phone today and I bragged to him how impressed I was with the Einstein.
T_bone
Albert, could you elaborate on the thinking behind and design of the implementation of your rod+iron block 'drainage' system, drawing vibrational energy from the SP-10's bearing well to the iron block? What exactly is the connection between the bearing well and the rod? It appears as if the iron plate is fixed into the plinth, in which case it would not act as a pendulum? Does a certain material have to be used for the rod? Is there a sequence of hardness (or shall we perhaps say, of combination of material density and elasticity constant?) which has to be followed from the bearing well material to rod to iron block? I am quite curious on how this is supposed to work.
The design is simple, the iron block is fixed (recessed) into the plinth bottom with stainless steel screws and has a threaded hole, bored very offset from center.
A large brass rod with polished end threads through the iron block, passing through the plinth, coming to rest against the bearing well of the MK2 or MK3.
Not only does this stop any tendency of the turn table frame to flex vertically, it offers a direct connection-drain point for vibration to flow into the massive iron block. The iron block is probably 15 pounds, it's a lot thicker than you think.
Iron is near the top of the heap in it's ability to absorb energy, making it ideal other than it's magnetic properties. Those magnetic properties are why it's very offset, on the opposite side of where the phono cartridge traces the LP.
Thanks to you and aaron for the great compliment of the look and design of the plinth.
Interesting comments on the Einstein phono stage. Is it quieter in your system than the Aesthetix Io? Do you think that the balanced version of the Einstein would offer any sonic advantage above and beyond the SE version? I guess this depends on whether it slots into a truly balanced system.
The Einstein is maybe 2 or 3 DB quieter than the Io, not really noticeable but audible if you listen all evening. I'm told the balanced version of the Einstein is anywhere from 15% to 25% better (their numbers) than the SE version. Perhaps the variation is due to your observation that performance could differ if the system was not truly balanced.
In what ways does the Io hold a sonic edge over the Einstein in your system?
The Io delivers music with what seems like an unlimited force behind it. When things get loud or complicated the Io just pushes harder rather than compressing or fumbling. I did not hear any errors in the Einstein but there was a sense it was smaller both in imaging and power.
Other than that, the two seemed to have identical RIAA curve or EQ or whatever you want to call the overall balance and tone of the music. Of course the all tube Io sounded more textural and warmer than the solid state Einstein but I could easily live with this solid state piece, especially if I had not heard the Aesthetix.
Almost forgot, the Einstein is actually slightly better resolution on some things. During soft passages when things are mixed up by the producer of the record, the Einstein can often pull out a tiny bit more vocal, making it more intelligible.
It will be interesting to hear my new Io Eclipse, which I should have back in the system soon. The factory says the upgrade is substantial over my Io Signature version.
albertporter on All Out Assault