User 510's Technics SP-10 mkII
Receiving:
some plinth design renders.
1) light weight. layered baltic birch plywood builds
Still working on final details for this design.
notes:
This plinth will allow either one 12 inch tonearm or one 9 inch toneam to be mounted. Presumably, any effective length arm in between these extremes will work as well. but I plan on first a 9 inch tonearm; the black Zeta. Then, over time, I will explore other tonearms/cartridges to see where the turntable's strengths are.
It only incorporates Baltic Birch in its build.
Finish will be multi-coats of lacquer.
Probably, in black.
I plan on making the first armboard out of purple heart. More details later as I develop them.
concept 5, light - medium - heavy . This is the same basic build but with
medium and heavy versions using more layers.
concept 5, light version, 3 views. Thickness this version is 3 inches, top
to bottom plate.
concept 5, medium weight version, 3 views. Thickness this version is 4
inches, top to bottom plate.
concept 5, heavy weight version, 3 views. Thickness this version is 5
inches, top to bottom plate.
here is a top view dimensional layout:
click on thumbnail to view/copy full sized pdf of the dimensioned drawing.
Adobe Reader required.
Please note. Above drawing is readable on 11 x 17 (US B size) plot.
If you can't print to 11 x 17, use the 'snap shot' feature in Adobe Reader to split the drawing into two separate 8-1/2 x 11 prints to improve readability.
The first plinth built is the heavy version. The more I thought about it, the more it seemed inevitable that a heavyweight plinth just seems logical.
At this stage, the plinth is complete in its glue-up but still requires much sanding before finish coating can begin. The purpose for this session is to check for fit of the sp10 mkII motor unit within the plinth, and also to fit the tonearm board , then layout for the drilled hole locations to mount the tonearm.
Laying out the tonearm location.
The pivot to spindle distance for the Zeta tonearm is 210.6mm. ( 8.2913 inches) Using the Clearaudio protractor, 210.6 is set on the scale and a 210.6 mm radius arc is scribed across the tonearm board. Anywhere on this arc will correctly set pivot to spindle distance. But we also need to consider a more optimal location of the arm relative to the rest of the turntable. In this case, because the SP10 mkII is a really large TT that was designed for a 10 inch effective length tonearm (as opposed to the 9 inch effective length of this Zeta) there isn't very much room to fit the tonearm without its mounting flange touching the side of the SP10 mkII chassis. As it turns out, there is just enough room to accommodate the Zeta and its 2.375 "dia mounting flange.
The one good thing about the Clearaudio protractor....it works as a layout tool
for custom tonearm mounting. Very well, actually. I bought mine when
they were new and could be had for approx. $150 usd. Now they cost more
and I wouldn't for the price they ask.
Look close and you can see the center punch for the main drill, but also a 2.375
dia is drawn around it in pencil using a drafters compass. This measure
insures that all parts of the tonearm will fit the area. Just barely.
Tools in use. A 5/32 inch transfer punch just fits the the Clearaudio tool
and serves as both scribe for making the arc, and punch for marking the drilled
hole start. The compass lays out for the mounting flange of the Zeta
tonearm to allow us to see that it will fit the area. A machinists rule to
set the compass diameter.
an alternate effective length considered but not used. The 228.6mm
effective length, with 18mm overhang listed in the owner's guide will work in
this application.
Early listening.
I can never resist a chance to listen to the rig before everything is done. There's this need to know.
In the above photo one can see the site method as well as the downstream components. I have three Lp spinners using MC cartridges of similar load resistance requirements. They all plug into the 1:10 step up transformer that feeds the multiplied signal into a Wright WPP100C phono preamp, which in turn sends its line level signal to the Classe' CAP 151 integrated stereo amplifier. The processed and amplified signal is then sent to a pair of NHT 2.9 flor standing loud speakers.
Both the SP10 mkII and the Thorens TD124 are using Denon DL-103R low output MC cartridges. Both of these cartridges have been installed into custom exotic wood bodies sold to me by Uwe. The difference however is in the DL-103R mounted to the SP10 mkII. This Denon has been re-tipped at Soundsmith with a Ruby cantilever/Fine-Line diamond stylus. The Denon in the Thorens still uses the stock tubular aluminum cantilever and conical diamond stylus. The Denon in the SP10 mkII uses a Panzerholz body by Uwe. The one in the Thorens uses an Ebony body by Uwe. There are differences in sound quality between these two Denons because of the different cantilever/stylii and also to a lesser extent because of the different exotic wood bodies.
Impressions:
Further notes on early listening.
JCarr's suggestion to move the phono cable ground from the stud on the SUT to
the stud on the phono preamp is a good one. Naturally.
The change was not huge, but definitely real and for the better. Improved focus,
ambience and tone. Slight, but audible and beneficial. Thanks Jon. Drop by and
tune my system up any time you like
Other notes:
I think I'll listen to the turntable a few more weeks while I sort out some
other non-audio related tasks to be accomplished.
What is noteworthy about the above sentence is that I'm willing to continue
listening to this turntable. It does have some very nice attributes. I would
include among its strengths terms like focus, detail (macro and micro), tone
quality and very, very good timing.
The very good timing manifests itself by fleshing out those brief, soft, quick
passages with a more precise articulation of it. This adds to the whole a
greater sum than might otherwise be heard. This particular Technics adds very
good texture to the musical picture, is what I'm trying to say.
So I find myself listening to the classical side of my Lp library with this TT.
Partly this is because the SP10 mkII seems very good at rendering classical
music but partly because it doesn't quite produce the same amount of energy
output on sixties/seventies rock as does my TD124 that stands near it.
In contrast, the TD124, an idler design from the late 1950's, has that ability
to make the leading edge of notes seem to leap forward with a good sense of
immediacy. To put it in different terms, the Thorens can cause my feet to move
involuntarily with its strong energy output while the Technics would having me
simply tapping those same feet to the same track.
But I'm not going to call the Technics laid back by any means. Compared to my
TD150, it is more punchy and slammy. But compared to the TD124, it can't match
that level of slam and visceral sense of drive.
I'm at a loss to explain why this is. The Technics platter is propelled by a
motor with a much higher amount of available torque than is that of the TD124.
Yet the Thorens defeats it in terms of energy output.
On the other side of this coin, the Technics defeats the Thorens in terms of
detail and focus.
But this brings me back to something I'm willing to accept; different record
players for different records....and I'm not going to ditch either the Thorens
or the Technics any time soon.
In the fullness of time I will do a complete disassembly and refurb of the SP10
mkII. I'll document it with plenty of photos as I have done on my TD124
projects. I'm just not going to dive in right away. No need. Things are working
quite well for the moment.
-Steve
10_23_2011 and still listening.
Just a short note to say that this rig is exceptionally good with The Moody Blues. In fact the turntable is more articulate than I am because I just discovered that I'm not finding the words I need to describe what is working well on these rock records from the psychedelic era. Clean tone. Sharp articulation. Driving rhythm. Deep bass. Clean highs.
Last week I played one side of the Pink Floyd Wish You Were Here album. The side with "Shine On You Crazy Diamond". It had me leaning back in the listening chair , closing my eyes and taking the ride. Sorry. I have no analysis of it to report other to say that I was able to get lost in that music. Good stuff
11_6_2011
still good!