Technics Linear Tracking Turntables – part 1
The analog audio bug has bitten me again…
In order to further assess the Artesania Turntable Platforms that were over for a review, a friend brought over a humble Technics J3, just for the fun of it. Interestingly, this cheap plastic unit managed to sound emotionally utterly engaging, communicating in a manner that even my best CD players failed to do.
And so, I was once again bitten by the analog audio bug.
Avid Volvere turntable, Grado and Benz cartridges and Musical Fidelity M1 Vinl phono stage kindly supplied by StudioAlkmaar
On the main picture and above: the best Technics linear trackers: SL15 on the left and SL7 on the right. But let me tell you all about how this story started.
First: a disclaimer:
The turntables reviewed here are 30+ years old. It is not uncommon for turntables of this age to have worn bearings or, especially in case of linear trackers, aged electronics causing misalignment of the arm. While I found no evidence of the former, I did encounter the latter, but I compensated for this by carefully re-aligning the servo settings. Nevertheless, I can’t rule out that some of the conclusions that I reach are clouded or influenced by the mere age of these players. That said: they all sound wonderful, and especially after recalibration, it seems that they perform just perfect.
Let’s start the show
It all started with the humble J3. On top of the superb Artesania Krion turntable platform, which is large enough to hold two Technics linear trackers at once – very handy for my comparisons!
After the positive initial experience with the J3, I decided to purchase a Technics SL-7 for myself. 35 or so years old, and still going strong. The SL-7’s top part (body and lid) is made of aluminium diecast and its bottom part (the dark grey bit) of zinc diecast. Given its diminutive size, the SL7 seemingly weighs a ton. As you can tell from the above picture, they use completely different mechanisms as well.
J3 and SL-7
98% plastic J3 on the left, 98% aluminium/zinc diecast SL-7 on the right – just kidding with those figures of course, but despite being built from different materials and having different automation- and arm mechanisms, the J3 also has some things in common with the SL7, which is something that can’t be said about the SL10 and SL15.
One thing that surprised me was that the platter motor mechanism is seemingly the same for the J3 and SL7.
Above: the stator part of the direct drive motor for the J3
Above: the rotor part of the direct drive motor for the J3
Above: stator part of the direct drive motor for the SL-7 – notice the similarity? All the plastic of the J3 is now aluminium and zinc diecast, but the SL-7 platter motor, while not a 100% copy, follows the exact same principle as in the J3. This is actually a much-reduced version compared to what’s in the SL10 and SL15, as we will see later.
Above: rotor part of the direct drive motor for the SL-7. The Magnet assembly is identical as far as I can see.
Above: the SL-7 platter, however, is thicker at the edges, and quite a bit heavier.
Tangential Tracking Principle
The tangential principle for all the Technics variants remains the same: a servo controlled worm wheel connected to a radio-dial-reminiscent rope that pulls the arm assembly. This is activated via an optical sensor upon dis-alignment of the arm as it is pulled toward the centre of the LP.
The whole arm assembly rests on a lubricated metal rod. Supposedly, this type of linear tracker manages to retain an amazing 0.1% tracking angle error. Well, that number sounds very good to me at least, but I’m not (yet) a vinyl expert and I honestly don’t know what tracking error percentages normal record spinners yield.
btw Cartridge shown in these J3 pictures is the standard EPC-P33 with a cheap replica stylus. We swapped it out for an EPC-P540 with original 540 stylus and it made a very, very large difference to the sound: much more refined treble, more low-level detail and more air with less ragged edges. The P33 had already been fitted with a brand new stylus but clearly, that didn’t help cover up that the cartridge can be bettered. The EPC-P540 did have less forceful bass though.
It may well be that normal pivoting arms cannot manage such low tracking error percentages as the Technics linear trackers, except on two places on the record. At least audibly I can attest to the fact that typically the last tracks on LPs sound worst. I’ve heard it countless times in friends’ setups as well as my own, when I still owned a Michell Gyro SE. Guess what? The Technics linear trackers sound as distortion-free on the last track as they do on any other track on the LP. And what’s more: I don’t hear any off-centre-related speed variations.
The downsides? Two that I know of. Supposedly these more complex systems are prone to break down. Well, all the linear Technics units I’ve seen, still play on nicely after 35 years. Second, you’re supposed to be able to hear the servo as it pulls the arm in short bursts every 2 grooves or so. Well, I don’t hear anything there either. Direct drive related downsides? Again, I don’t hear them. But I do hear the upside of Quartz lock though: perfect pitch and superb transients.
But I’ve only got MM cartridges to play with. The story might be different with the more sensitive MC variants. After all, the signal is much weaker and needs to be amplified more, and in the process, more rumble might be picked up. I don’t know. And I don’t really care. They are just too much fun.
In the SL7, the arm assembly is built right into the cast aluminium lid, as opposed to being built into a separate folded metal part in the J3. Contrary to what is said on the Vintage Knob site (“The SL-7 is an SL-10 sans built-in MC preamplifier, with less aluminium and more plexiglass”), the SL7 has very little in common with the SL10 and SL15. The Vintage Knob is right in that the SL7 lacks a MC to MM preamp, but otherwise, the info is wrong. SL10 and SL15 are actually practically the same machines, but the SL7 stands out.
Compared to the earlier SL10 and SL15, the later SL7 has completely revised electronics, a simpler platter motor and a different arm mechanism. The latter still works via motor-worm-wheel-waxed-rope, but the plastic assembly covering the rope is very different. The arm itself is also slightly different, as is the locking mechanism. Oh, and the SL10 and SL15 have a mostly metal puck, while the SL7 has one entirely made out of plastic. The SL7 and SL10 also sound very different. “Oh dear, there he goes again”, some readers might think. Yes: I’m saying that I hear clear differences between SL10/15 and SL7 using the same cartridge and styles, and the same 1.4-gram tracking force (needle pressure).
btw: Technics recommends 1.0 – 1.5 grams, aiming for a centred 1.25 grams. Importantly and conveniently, all T4P cartridges and stylii are made to this spec. Even so, I found that it is good to check the actual tracking force with a digital meter and adjust accordingly, not only relying on the mechanical indicator.
Initially, I noticed that 1.4 is just right: 1.5 makes for better bass but kind of suffocates dynamics and fluidity. Lower settings improve fluidity and air but at the cost of bass power. For the remainder of part 1 of this review (this page), I used all Technics T4P turntables with a calibrated 1.4 grams tracking force. However, recently I found out that the EPC-540 cartridge in the SL-7 was slightly loose and I tightened it, without giving it another thought. When I had a friend over a few days later and we listened to the SL-7, I found that it sounded a bit restrained and too controlled. It then occurred to me that my preference for a higher than usual tracking force may have sounded better only because the cartridge was not fixed in place well enough. I recalibrated to 1.25 grams and yes indeed: back was the fluidity and agility. So, from this point forward (next page of this review) I calibrated all Technics players to 1.25 grams.
For best tracking, as well as lowest wear, some believe that tracking force better be nearer to the highest value that the manufacturer recommends, while others believe that it can better be set nearer to the lowest. Opinions on this matter differ, and even the experts can’t seem to agree, so I suggest you experience for yourself and form your own opinion.
Tracking Force (Needle Pressure)
How did I manage to measure tracking force with these Technics players? It’s a bit tricky actually because they’re made to be foolproof. They won’t lower the arm unless there’s a record on, and not unless the platter is spinning. Here’s how I do it. First I trick the player into thinking the lid is closed by pressing the contact switch, then move the arm to the middle position and switching off power so that it stays there. Unfortunately, it is really, really dummy proof and it raises the arm again right after switching off the power.
Ultimately I found a way to jig the arm lowering mechanism, simply by blocking the lever that takes it up again. I then place a digital needle pressure reader in the right spot and carefully lower the lid.
Oh, it looks like if one really wanted, the counter weight’s position could probably be changed slightly, further enabling tweaking (negating) the spring’s tension.
That’s an original Technics EPC-P540 in the SL7: a big improvement over an EPC-P202 which itself seemed to be an improvement over the P24, but perhaps my particular P24 was not in optimum shape, as apparently all the Technics P-mount bodies are the same. There’s a scale indicator for the needle pressure near the adjustment screw all the way at the back of the top cover, under the arm, but it’s not very precise. It’s supposed to be at 1.5 grams in the middle position, but I already measured enormous differences between the various players when set to that middle position. The screw tensions a spring that adds pressure to the metal weight that is at the end of the arm. This is how these turntables are able to play vertically. However: too much spring tension can have a dynamics crushing effect (Thorens owners take note). That’s why I like to keep it slightly under the recommended 1.5 grams.
Sound – J3 versus SL7
The big difference in sound between the J3 and SL7 is in timbre/tonality and dynamic behaviour. While the J3 is very lively and engaging and has a beautifully open midrange and treble, it is also devoid of colour and sounds a bit synthetic. Pianos sound more like keyboards. And bass, while fast and articulate, is less than full-bodied. The J7 sounds much fuller, yet less coloured. It’s almost as if you can hear the calming effect of using lots of aluminium/mass. However, the SL7 sounds dynamically more compressed: all sounds being seemingly equally loud.. Not good. Setting the needle pressure to 1.4 grams helps, but not enough.
Next suspect item was the clamp. While it may look loose and wobbly when touching it hanging from the lid, it actually contains a spring and is pressed tightly to the record when the lid is closed. That’s the other reason why these players can play vertically. But I remember from earlier turntable days that clamps, especially heavy ones, do more damage than good. They improve sonority and calmness but, you guessed it, they crush the dynamics. The player still sounds fast (it doesn’t have pre-ringing, like a CD player) but still it’s like the transients are stopped in their tracks before reaching full potential, in a word: they sound topped off. Removing the SL7 clamp is not very difficult, but it requires unscrewing a lot of screws, and careful removing of the plastic part of the lid. With the SL10 it’s a little bit more fiddly as it requires the removal of the plastic inside cover that can’t easily be totally removed.
With the clamp removed and used with the same EPC-P540 cartridge in the J3 and SL7, the SL7 now sounds just as fast and dynamic as the J3, but with much fuller tonality and no synthetic feeling whatsoever. For fun, I momentarily placed the puck back on the record manually, without the spring, but even that has an influence on the sound, and I don’t like it.
The same owner of the J3 then brought along an SL-15. Turns out he has a whole fleet of these preciousnesses. The J15 is the big brother of the J10 and it is built almost exactly the same. Obvious difference is the track programming section on top and this is actually very cool: the player scans the record and makes a distinction between the tracks which can then be programmed to play. Say you like only track 2 and 3 then just put on the record, close the lid, press the buttons 2 and 3 and off you go. Well, not always. Maybe the electronics are a little off, or not all records have clear enough distinction between the tracks, but it doesn’t always work. But never mind: the rest still works beautifully, and in playing the SL15 sounds a lot like the SL10. Please note though that the record clamping puck for the SL10 and SL15 is made mostly of metal as opposed to all plastic, and that this means that its negative influence on dynamics is even bigger than with the SL7. Because I don’t own the SL15, and the owner doesn’t want to have the puck removed, I will leave it aside for further comparisons.
Coming Up Next
In the next instalment of this review, I will directly compare the SL7 and SL10 with the same EPC-P540 MM cartridges, and I will see what the influence is of the Artesania platforms on which they sit. Also, I have obtained another SL10 with an original EPC-310-MC cartridge and I will discuss the benefits and downsides of MC versus MM by means of 2 different phono preamps: the Musical Fidelity M1 Vinl and the Jeff Rowland Cadence.
What’s more: I managed to borrow a beautiful Avid Volvere with SME 309 tonearm from Ben Hoedjes, proprietor of Studio Alkmaar, an audio store in Alkmaar Netherlands, that sells new and second hand high-end audio equipment.
The Avid Volvere will be compared directly with the best of the Technics direct drive crop. Will the Avid crush them? Or are the differences not all that large? All will be revealed in the next instalment!