124 in Slate

Seattle, USA.

The Thorens Td124 in a heavy Slate plinth

At this stage the TD124 is in good mechanical order and can sound --very good-- no matter which way it is mounted. See the other pages within this project for details of all the repairs and maintenance that was done.

The decision was made to build a very solid plinth out of thick slate in order to optimize the deck. The solution would not be limited to just a plinth, however. A dedicated turntable stand was also on the drawing board. To top it off the tonearm and cartridge are to be replaced with better quality units currently in my possession.

The new plinth: Slate, as a base material, was chosen for its exceptional resonant energy absorption qualities.

Slate: It is a metamorphic rock. A shale-type sedimentary rock. It does not have the hard crystalline structure of most other rocks, like granite. Compared to granite, slate is less resonant. Rather, slate is a softer rock that can be easily split along its layer lines using manual (non power) hand tools, or it can be carved into any desirable shape. The most common use is for high quality, long lasting roofing tiles in residential applications. Another use is for attractive counter tops within the home. Yet another use is the ultra-flat bed surface underneath the felt fabric in high quality billiard tables.

For my purposes, the layered structure, high density and absolute rigidity of it are qualities that allow the slate to absorb the acoustic energy and other mechanical vibrations emitted by old vintage players like the Thorens TD124 and its well known competitor back in the day, the Garrard 301 and 401 idler drive turntables.

Jonathan Weiss:

To get the slate I hooked up with Jonathan Weiss of "Oswald's Mill" in Pennsylvania. His slate comes from a local --ages old-- slate quarry.

When polished this Pennsylvania slate demonstrates a dark black dominant shade but with just a hint of blue. There are occasional swirls of lighter colors. Like nothing I've seen before.

From the quarry he takes the large milled slabs of slate to another nearby manufacturing facility where it is cut to dimension via cnc water-jet. This is where I provided some essential data. Based on measurements taken from my TD124, I produced cad drawings for the water-jet programmer to develop his cut paths. I also provided some hard templates as a reference check to make sure the cut-outs fit the turntable without interference of fit anywhere.

The plinth design:

Here is the original concept I rendered as a 3d sketch. It provides a 2 inch border around the Thorens and uses two stacked slabs, 2 inches thick, and then 3 slate blocks for feet. Gravity holds it all together. No threaded inserts. No dowel pins. No glue. The internal water-jet cuts look like this: The textured top surface is called a "cleft surface". It is done by hand where the slate worker hand chisels the rock parallel to the layered structure.

The first parts:

After we had finished parts there was a discrepancy. The inner contour that fit my early model TD124 like a glove had some clearance issues in the vicinity beneath the armboard support structure on Jonathan's later Td124. The discrepancy is about dimensional variation in the cast chassis of the Thorens that has occurred during the eight years of production for the mark 1. I've noticed other variations as well. Note that this is NOT a MK1 versus MK2 difference. Both tables are mk1 but mine is an early model circa 1958/9 with a 4 digit serial number (2729) while his is later with a 5 digit serial number. Obviously the Thorens factory produced different casting patterns over the years and there were some minor changes made. More on that later in another section of the TD124 dept.

The look:

Jonathan styled his plinth with slightly different detail. For a look here's his:

He's retained the original stacked-slab configuration and then cut rounded corners and edge radii along each perimeter. I like the look quite a bit. Photo by Cynthia Van Elk. For more of Jonathan's slate designs link here.

The weight and rigidity of all this slate serves to provide stability to the turntable mounting. See the top photo. There is 52 lbs of slate beneath the chassis of this TD124. I term this plinth layout of mine as a "two-tier skeleton" for its open bottom and spaced-apart two-slab build. Each slab is 2 inches thick. Between the two slabs are three 2 x 2 x 1-inch cubes of solid slate acting as support spacers. For the feet more solid slate is used in 2w x 2w x 2 inch high dimension.

Metal fasteners: The only metal being used in this build-up are the fasteners that clamp the Thorens cast aluminum chassis to the upper slab of slate. In this case a brass-threaded-rod is screwed through the aluminum adjuster and then into the cast chassis of the thorens at the top. The rod fits through a hole in the slate, through a special pvc resonant dampening grommet insulator, then an extra-thick aluminum washer and finally is secured by a plated brass thumb-nut from underneath. Btw, thread size is m5 x 0.8mm.

The Stand: Beneath the slate plinth is a new dedicated turntable stand. I intended for this stand to offer exceptional stability by making it rigid and massive. The stand has legs constructed of laminated 1x4 'poplar' hardwood, 4 layers thick. The two massive shelves are laminations of stacked Baltic Birch plywood totaling 2 inches thick each. The turntable stand is assembled with adhesive. Once the glue was dry, 48 hardwood dowels were installed through the legs and shelves to add further strain resistance. No metal. Under load the stand appears rigid and flex-free.

Armboard and arm:

In order to mount the Graham 2.2 tonearm to the Thorens I needed to construct an armboard. I chose 1/2 inch thick ebony hardwood as the board material. I found the ebony at a local "Rocklers" wood workers supply store in Seattle. At Rockler's there was on hand an interesting stock of exotic hardwoods all neatly cataloged. A haven for those who work wood. The ebony was priced at $60 per bf. I selected a piece that was 20 inches long, 3-1/8 inches wide and 1/2 inch thick. I paid ~ $23.00 after sales tax. There was enough material left over to make another td124 armboard should I want to.

I used the alignment jigs and fixtures supplied with the Graham to align arm and cartridge to the TD124. The cartridge is an Ortofon MC Jubilee. The alignment went smoothly resulting in a "spot-on" overhang and zenith alignment. VTF was set to 2.5 grams using a Shure sfg-2 scale. The VTA working range was adjusted over time by ear while listening to familiar Lps. The Graham 2.2 has on-the-fly vta adjustment capability which makes this easy.

Listening Impressions

Note: initial listening through the TD124 on slate was done with the chassis of the TD resting directly onto the slate. The rubber isolation mushrooms were not used.

For this part of the report I can't avoid making subjective comparisons between the arms and cartridges being used on the Thorens, and then making an A/B comparison between the Teres 145 and the Thorens using these same arms and cartridges .....all this while playing through the same downstream components. Hopefully the impression will be realistic and useful to the reader.

Express Machining RB 250 tonearm with Denon DL-103R MC phono cartridge:

For a time I listened to the Thorens in this "slate plinth" using the Express Machining RB250/Denon DL103-R tonearm and cartridge (mushrooms not in use). The armboard in use was/is an original looking painted black piece of dense fiber board that I had previously drilled and trepanned to fit my Rega-based tonearm. I was very impressed by the sound coming off this player with this new setup. Compared to the previous plinth, a heavy plywood open box using the Thorens rubber mushroom isolators, the TD124 now had a quieter, blacker background behind its music. Faint musical details became better articulated. Some sounds not previously heard became apparent. This was an obvious improvement.

The Graham 2.2.

The Graham 2.2 with MC Jubilee mounted on the TD124. I've heard this arm and cartridge combination before on my Teres model 145. Much of what I hear now is comparable to that.

Mounted in the slate plinth and not using the Thorens rubber isolation "mushrooms", the TD has an inky black background behind its music. To my 'ear' the s/n ratio is comparable to the non-suspended Teres. Drop the diamond into the lead-in and there is...... a hint of a very faint trace of low frequency surface noise. The stylus riding over smooth vinyl. Barely perceptible.

Disclaimer: Of course you DO need to have an idler turntable that is in good mechanical condition. That has been a prerequisite and the early focus for this project.

One difference between hearing this arm and cartridge on the Thorens versus the Teres is in the 'dynamics and drive' departments. The Thorens, with its idler driven platter, delivers dynamics like no belt-drive turntable that I've heard. Drums attack more suddenly while reaching further into the space of the listening room. There is a force behind the rhythm that causes your feet to move involuntarily. Play the same Lp on the Teres and you still move your feet but with a little less compulsion. This difference is more noticeable on some recordings than on others. For instance, Brian Auger, "Closer To It". The popping congas, percolating as they do are much more alive and palpable in the listening space when played through the TD124 than through the Teres.

above photo: listening to the Teres for comparison in the same environment.

The Graham tonearm delivers a very refined sound. By refined I mean that its musical output lacks any trace of edge or harshness. It finds faint musical details and nuances within the Lp grooves and articulates them. It delivers pure clean tones. It fleshes out the timbres and textures of musical sounds. With some Lps there is a sense of the original recording space. The MC Jubilee seems to be a fair match to the Graham. Tracking over difficult high amplitude tracks is very, very good. I've never heard even a hint of miss-tracking with this arm and cartridge. The Jubilee delivers a vibrant alive sound. There is 'air' surrounding the strikes of notes allowing us to hear with clean definition. High frequency sounds are extended and clean. Midrange frequencies are vibrant and intimate. Bass is textured, sharply defined and has good solid weight. I have read descriptions of this arm elsewhere that label it as an "analytical" sounding arm. My take; If this is analytical, then I find it agreeable. More likely, the pairing of the Graham and Jubilee is a happy marriage that produces goodly amounts of detail without losing sight of the scope and flow of the music it reproduces.

Compared to the Thorens/ExpressimoRB250/DL103-R, the Thorens/Graham/Jubilee delivers a much more detailed presentation. There is a greater sense of the recording space ambience. There is less bass slam. The sense of dynamic explosiveness seems tamer. Drums don't reach into the space of the listening room quite as far nor with as much force. Rhythms and percussion are less palpable.

More notes: June 13, '07

I think the TD124 works well in the slate plinth. When transitioning directly from the previous wood plinth, using mushrooms, into the slate -sans mushrooms- the TD quite noticeably has a quieter background and then articulates finer musical detail. This is noticed while making no other change except for plinth mounts.

Over time I found that I liked the TD124 better while using the Express Machining RB250 and Denon DL-103R arm and cartridge than with the Graham 2.2/Jubilee. Reason: The essential idler drive character. The unstoppable rhythmic drive. Dynamics that rush into the listening space. This was more apparent here than with the Graham with Jubilee.

More notes: October 3, '07

The Expr. RB250 with DL-103R is still in the slate. What this arm/cart combo lacks in detail and refinement is more than compensated for with dynamic punch and immediacy. That is not to say the setup lacks detail or refinement. This is very enjoyable in all ways I can think of. I'll try other arms in the near future looking for more of the qualities I prefer.

More notes: July 6, 2008

See notes on "tuning arms and cartridges". Link here Through some try-it-and-see experimenting I found that the addition of mass helps greatly with the performance of the Denon DL-103R cartridge. I constructed a headshell weight. A carbon fiber/brass/carbon fiber layered build held using super glue to hold the three layers together. This weight fits between the headshell of the tonearm and the Denon. In the case of the Expressimo RB250 tonearm it was necessary to attach additional weight to the counterweight in order to balance the added mass over the stylus. With this done I was impressed with the sound and listened happily to the turntable this way for quite some time.

After some time it occurred to me that I had not heard the mass loaded Denon in the Graham and that it would only be fair to mount this up for an audition. Here's a pic:

Above photo: Uwe Ebony bodied DL-103R, with headshell weight, mounted in the Graham 2.2.

As it turns out the Graham 2.2 comes with an additional bolt-on piece to add more weight at the counterweight end when needed. With this mounted I found it well within range to balance and accurately set the vtf for this assembly. VTF was set to the recommended 2.5 g. Because of the added height I was unable to use the Graham overhang alignment jig. However a 2 point protractor (Baerwald style) set the overhang and zenith angle just as nicely.

Sound?: Very nice. Unlike with the MC Jubilee in this setup I don't feel like I'm missing any dynamic rush or rhythmic drive. Tones are pure and realistic. Crank it up loud and this front end source does boogie. Play classical and it seems to deliver the essence in a very pleasurable way. Excellent detail extraction for a DL-103R. Jazz gets a lot of play.

Associated equipment:

	phono stage: Wright WPP100C
	Classe' CAP 151 integrated amp
	NHT 2.9 4-way tower speakers
	more system details: link