Technics SP-10 Tonearm Pod instead of Plinth/Base

Dear Weisselk: +++++ " This is yet another of those "to each his own" audio discussions " +++++

No, it is not absurd or " bad idea " ( it is only a different " road " and you don't have to like it. ) to run the Sp-10 with out plinth if you have the right " tools " ( including know-how ) to do it.

Certainly your bad experiences about means you don't have those right tools.

Anyway, if what function to you is a different " road " good for you this is the important issue: that you be satisfied.

Like Jsadurni I'm satisfied using no plinth.

Regards and enjoy the music,
Raul.

Dsa, I think there may be some confusion over the meaning of "pod" in this discussion, but I'll come back to that.

A couple of years ago when I got an SP-10 Mk2A, I started researching plinth design. Initially I cut out a 20" X 18" sheet of 3/4" particle board (not even MDF) so I could mount an arm to enjoy the table while designing and building a proper plinth. I experimented with different mountings, from the Technics bottom pan directly on a shelf to various absorptive materials either under the pan or supporting the particle board frame. I have not liked any springy support and the differences between stiffer support and no support are minimal. But unlike Lew I've not had any problem with the table moving from start-up torque.

Researching plinth design was initially disappointing since there is little info on SP-10s compared to all the rim-drive sites for their Garrards, Thorens, Lencos, etc. One good source for information is the DirectDrive site (see review of plinth materials) but I can't access them now to provide a link. Another is Soundfountain which has already been mentioned. Many great ideas are available from Albert Porter, even if you choose not to buy one of his plinths. I'm sure the OMA slate plinths are excellent but they are costly (at least for my retiree budget).

One other thought for plinth material comes from Townsand Audio, make a mold of the proper plinth and use plaster of paris, possibly including lead shot. Still messy but easier than concrete.

Since I had met Raul and had several discussions with him, I ask for his opinion. Here is where I think there may be some misunderstanding. When Raul says he favors a non-plinth design, my understanding is that he is saying it is not a standard box frame or solid wood plinth. Rather it is similar to what I'm using except even smaller in dimension - just enough wood attached to the platter base to mount the tone arm. Then he places his AT suspension feet underneath the bottom pan of the motor unit.

Many commercial turntables include what is called an arm pod but they are attached to the base mounting the platter/spindle housing in some fashion. I believe this is what Lew is addressing when he talks about the mechanical integrity of the platter/arm mounting. Very few offer an isolated pod for the arm which could simply be picked up by itself because of the lack of a mechanical connection, other than weight. While I'm not an engineer, much of my reading discussed the importance of stability between platter mounting and arm mounting. Given the microscopic undulations of the record groove, the need for such stability makes sense to me if we want to insure the only vibrations picked up come from the stylus in the groove. And even with a very massive separate pod to stabilize the arm, imagine moving it for the small increments required for proper alignment overhang and offset!

Anyway, for a long list of reasons, my proper plinth has not been built yet, but I must say my SP-10 sounds pretty good bolted up to the single 3/4" board.

Pryso, You got the same idea I had re Raul's non-plinth. When I described it here pretty much as you did, Raul posted that I was incorrect, that his tonearm IS on a discrete outboard mount of its own. While Raul is not alone in preferring that type of set-up, it does go against the prevailing philosophy that there needs to be some rigid physical connection between bearing and tonearm. I personally am not going to say that Raul's SP10 can't sound good. I have just made my own decisions in the other direction, in favor of mounting any tonearm in or on the same physical structure that houses the turntable mechanism. The analogy that is vivid for me is that of a race car driver who gets in an accident with or without his safety harness buckled up. The link between bearing and tonearm assures that both elements of the playback system remain coupled during those rough moments.

LEWM: thanks for the tip on the cutout. Thanks also for the explanation of the arm length issue. Weisselk has also suggested that removing the base of the SP-10 could be a good idea, especially sonically.

Raul and others seem to have had success with a plinthless setup. It's looking like slate for a plinth or semi-nothing. Reports coming in on the cement option are poor. I imagine that resonance is the problem (like granite).

Hello Pyrso: Yes, there is a plethora of info on plinths for the rim drives, and much less for DD crowd. The OMA plinths are expensive...but I starting to believe that a finely made slate plinth is the best (plinth) option. The OMA models look exceptionally well made.
Yes (and Lewn said this earlier too and details it again above)- I think Raul's no-plinth setup is more correctly a semi-detached armboard setup. However, dibs to Raul for the application of his clever thinking.
Plaster of Paris, eh? Any other takers on that idea? Making the mold could be a pain though. I have trouble laying carpet tiles to fit a room let alone making a mold!
Yes- there is a strong valid argument for keeping the tonearm connected to the turntable proper
I'm thinking it's like when there a two cars drive next to each other, trying match speed, and a passenger attempts to pass a egg out the window to the other car while both cars negotiate pot holes and speed bumps!
It might be good 'ol 3/4 chipboard for a standby plinth after-all.

Oh, but those OMA slate plinths...

I have an SL-1000 MK II. That's an SP-10 MK II in the original Technics obsidian base. What is wrong with it and what improvements would I be seeking by changing to slate or some other material? I have read threads like this often but have never yet been prompted to try something different. Part of this is a respect for the integrity of the original design and part is skepticism. If Technics was able to build one of the finest turntables ever made available, would they not have provided a very suitable base? Would they not have experimented with many materials and different masses? When this turntable was offered it was extremely well funded and very capably engineered from a cost no object perspective. What did Technics do wrong?