Technics SL1000 MK3 (SP10 MK3) performance/value VS modern turntables?

@atmasphere 

I think the SP10MkIII is better than the new 10R because it has so much more torque. But a good deal of that was so it could be used for LP mastering and I suspect that was not their goal with the newer version. 

Yes but no one has addressed the major problem with the SP10mk3 - that is the antiquated error correction circuitry based on obsolete chips that results in errors and overshoot.

The Technics SP10 servos use algortihms to estimate predicted errors and employ rapid response times (limited by the technology of the day). The servo action includes error and overshoot.

It is no better than the jitter endemic in digital reproduction, and sounds like it to me.

I am surprised that on one offers a modern improved speed control system for the SP10mk3 motor.

Since the Technics was built there have been significant advances in technology. We now have computer simulation software to model motor behavior and generate more accurate algorithms, from which the input parameters are derived. There are now faster chips and amplifiers for driving the motor �- PWM�s are switching at a trillionth of a second today.

The problem is the Technics is full of obsolete chips and trying to optimize the feedback loop would be like trying to tune a car that has a very basic engine management system. You would probably be better to throw the boards away and start afresh. 

By comparison look at the error correction systems employed in newer TT's such as the NVS & Monaco. 

Modern control systems, with enormous computing power, can use statistical analysis, and a continuous shrinkage technique to improve the prediction of error on the fly - resuting in less overshoot and more stability.

In other words with new technology, the input parameters for the speed correction/servos are NOT set in concrete, as in the SP10mk3, they can now be calculated on the fly.

If you believe you cant hear it - have a look at the reviews by owners of the new upgrades to the GP monaco TT's. Omly a few years ago they claimed their TT was state of the art and perfect ( just like CD ). now they have further refined their electronic servos and low and behold - the improvements are audible. And their first TT interation error correction makes the Technis SP10mk3 speed controller system look like the dinosaur it is.


Explanation of Overshoot

 Algorithms are used requiring control inputs based on measuring past errors, the present error and a prediction of future error based on the current rate of change. 
Past errors (Integral) are included to accelerate the process and remove any steady state errors in the present error (or proportional if you want to get technical). 
Since the integral term responds to an accumulation of errors from the past, it can cause the present value to overshoot the set point value (where you want to get to).

In terms of correcting the present error, if the gain is too high you get instability, too low and you get a less responsive controller that may not deal with fluctuations. 

The prediction of future errors (called the Derivative) is required to minimize overshoot.

So, summarizing this then these inputs have to be balanced to maximize the correction and minimize instability and overshoot. There are always tradeoffs.

I visited the Krebs website and found nothing in the price list at 2500$ for the modifications of the Technics MK3 you get to max 1200$ and in any case its modifications do not convince me.

If Technics SP10 owners are contemplating the krebsupgrade they should be aware that there are legal exclusions of liability for any breakages incurred during the modification and that the modifications are irreversible.
I quote from the krebsupgrade website -

Some Legal Items:
All due care will be taken with your precious motor, however there is a remote possibility that a fragile or previously damaged but still functioning part could fail. In the unlikely event of this happening. We will do our best to repair or replace this part but we cannot guarantee a fix and cannot be held accountable for this failure.

FREQUENTLY ASKED QUESTIONS
If I dont like the upgrade can it be removed?
Due to the nature of some of the materials used the complete upgrade cannot be reversed.

I also see that no measurements or objective tests have been provided to support the krebsupgrade claims. 

Personally if I had an SP10mk3 I would, at the very least, get a full service of the electronics done by Fidelis Analogue that includes an upgraded chip to replace MN6042 that does actually imrpove the original design, and for which Fidelis has published test data supporting his claims.

Lewm - just to be clear

I use to listen to an SP10mk3 just about every night for about 3-4 years back in the early 80's - purchased NZ new, Technics EPA100mk2, and various cartridges bog standard and immaculately maintained by a precision engineer, fully qualified, who owned the largest die cutting machine in Australasia.
Over the last 40 years I've heard it in multiple systems with different arms along with multiple L07D's and many Sp10mk2's which are more common.
The last SP10mk3 I have listened to at length was fully updated with Krebs mods, Porter plinth, SME V12 & Ikeda 407 mounted.

With regard to the servo system I cant understand why you cannot conceptualise that advances in motor controller technology might improve the SP10mk3 significantly. Are you still using the computer you purchased in 1978, if indeed you had one.

As far as vintage audio goes, rare items are now like vintage cars - if you modifiy them chances are you diminish the value. Do you not think that folk who are interested in modding their equipment should be fully informed when making their decision. All I did was point to the website of the modifier, I did not make any subjective statements on the quality of the work or efficacy.
The modifier in question on his website states that the mods are not reversible, and if any breakages occur in the modification process, the modifier eschews any legal responsibility due to the age of the equipment.

@jpjones3318

Hi Dover,

The Technics "Quartz Locked" units utilize PLL motor control.

So you believe the frequency generator, speed and phase control circuits meet current state of the art performance do you, even though the SP10 uses 70’s chips and we now have chips capable of switching at a trillionth of a second, and computer power millions of times faster today ??

If indeed the SP10mk3 controller is as crude as described in their advertising - then basically it is correcting instantaneously any speed deviations calculated using data generated from those 70’s chips.

It is no different to digital jitter in my view. The advertising implies there is no smoothing of the error correction.

I note that Technics again claim in their advertising that the higher platter mass of the mk3 ( 10kg ) is key in generating a more stable FG used in the speed and phase control circuits.

By comparison the Victor 101 calculates the error over a period of time and feeds the correction in over a period of time to "smooth" the correction.

Also as you would know the L07D relies on platter mass for stability, the error correction only kicks in when the speed deviation is beyond quite a wide range.

It is clear that Technics, Victor and Kenwood, 3 of the supposed best direct drive TT’s from the 70’s, had 3 quite different views on how best to implement speed control of the platter.

They must have had 3 disparate views on how speed control circuits affect sound quality.

Since I believe you own all three decks - I would be curious to know if you believe they each have a sonic signature.

I have heard multiple SP10mk3’s and L07D’s and each motor has a signature sound to my ears that is readily identifiable irrespective of arm/cartridge. I have not heard the Victor, but I have heard the Thrax which I believe uses similar principles to the Victor 101 in the way the error correction is implemented.

@jpjones3318



I think you misunderstand the point I'm making - I'm not saying the Technics is "computing" - I'm saying the speed measurement and correction  system is built on old technology. Your own improved chip replacement circuit has already demonstrated measureable improvements are possible.

Even the reference quartz crystal can be producted to much higher tolerances today.

At the end of the day do you agree that in principle the FG servo is a negative feedback system that corrects speed anomalies - right ?

Quartz reference crytals have inherent jitter - right ?
The PLL circuit has filter out the jitter to deal with this - right ?

Re the Victor TT101 - the averaging of speed errors and correction system, I dont have time to trawl the net - this was based on comments by both an owner and a designer of a current production high end direct drive.

Sound of the TT's

With regards to the SP10mk3 and L07D - 
I have friends that own these and have listened to them for over 30 years with a myriad of arms/cartridges. Also had them in my own system.
If I were to summarise their sonic attributes - to my ears the SP10mk3 consistantly presents a leaner, cleaner more precise presentation. The L07D to my ears consistantly sounds slightly courser, slightly less precise.

I cant say this is due solely to the speed correction systems, because the mechanical structures, including platter, plinth and mounting are substantially different.

But I can say that the differences are consistant and audible to me across muiltiple systems - enough to blind test and identify each deck in a system that I know.

@lewm

What I wonder, however, is why Dover is so intent upon discrediting these vintage turntables. It’s all very well to love and prefer whatever it is that you own over all other TTs, but why does that require that all other solutions to the problem of playing a record are wrong or sub par?

I think you read too much into comments.
When someone claims X is the best, I offer my opiinion if I have owned or heard X in a system I know well.
If I prefer Y to X, it does not imply that X is junk - it may well be the 2nd best TT on the planet.

I have consistantly stated that I am not opposed to direct drive system, or any drive system, and offered some possible explanations. I am inquisitive by nature and like to learn as much as I can.

For me discussion and sharing of ideas is critical to learning.

As far as turntables go design integrity and quality of implementation is arguably as important as the actual drive system chosen.