Techdas V or Primary control Kinear

[perart1]

OK...so I am contemplating adding another turntable and have narrowed it down to either of the above.
My first question is regarding the TechDas V . On the recent Premium version there are two additional pitch controls compared to the previous one. I assume that these vary the torque. None of the comments on the Premium mention them! Can anyone confirm this and clarify the effect this has on the records being played.

Secondly, the Kinear has the ability to vary the torque, with three settings. Can anyone who has experience of the Kinear comment on their effect. There are few reviews of the turntable (most focus on their tonearms) so if anyone has been able to compare them I would be interested in their observations.

Yes I know; you could not find two more different TT ; aesthetics, technology, drive systems, footprint etc. Just shows what an open mind i have. either that or confused

 

[Another Johnson]

Perhaps I am overthinking this, but from the perspective of a mechanical design guy, the needle drag and bearing friction would seem to dictate the actual load.

Torque beyond that necessary to cover the actual load would seem to be superfluous.

If the motor can’t meet the load, speed will drop until the load is balanced. If the motor provides more torque than is necessary, the speed will increase, again until it is balanced against the load.

What is the purpose of a user adjustable motor torque?

 

[thekong]

I am no engineer, so can’t talk about the technical advantages and disadvantages of having variable torque. However, as far as I understand, you can change the torque of an AC motor by simply changing the driving AC voltage.

I have asked my engineer friend to build me a dual phase AC motor controller that has variable AC voltage output for an 110V motor. With a slightly lower voltage, say 90V, (the speed is still stable), the sound is a little more refine and has a slightly blacker background. With 110V, the sound seems to have more drive. Certainly not day and night difference, but good to have if you like to fine tune the sound to your liking.

I believe the VPI motor controller (and maybe the SOTA/Phoenix Engineering controller) also has this feature of starting the motor with full voltage/torque, and then lower the voltage to around 87-90V after the platter reaches correct speed.

 

[perart1]

OK....so I guess that it was inevitable that we would get into a discussion about DD and torque. There is plenty of info. on the Web, some of it contradictory. If people are really interested, there is a useful site ; korfaudio.com that has a useful blog for the non engineer (like myself) that discuses the various issues around TT drive systems.

It will be interesting to see if anyone is able to provide information relating to my questions.

 

[Another Johnson]

OK....so I guess that it was inevitable that we would get into a discussion about DD and torque.

Since your question was about torque adjustment capability, it was inevitable.

The idea of start up torque being different from steady state running torque certainly makes sense. The time to accelerate a gigantic mass from 0 to 33.33 or 45 will be shorter for a motor with more torque. Is that what’s going on here?

It would be nice if someone who owns or sells or has reviewed these to chime in with the answer. Maybe while they’re at it, they could elaborate on the reasoning.

 

[perart1]

Yes you are right Some TT's apply high torque to accelerate the platter for few seconds to get up to speed to overcome the initial inertia and resistance and then drop the torque to maintain the speed. But very few give you the choice to vary the torque. The Primary Control Kinear does and the TechDas V premium has what they call a' 'pitch button" that's not on the original model. When discussing the TT and referencing the previous model the only difference mentioned is that it is milled out of a solid billet of aluminium. Some reviewers must surely have asked the question? It presumably is referred to in the operating manual.

 

[abeidrov]

OK...so I am contemplating adding another turntable and have narrowed it down to either of the above.
My first question is regarding the TechDas V . On the recent Premium version there are two additional pitch controls compared to the previous one. I assume that these vary the torque. None of the comments on the Premium mention them! Can anyone confirm this and clarify the effect this has on the records being played.

Hello, I checked the Techdas site, and I do not see any additional pitch controls. It has the same 2 buttons that other models have like my AFIIIP. Do you have a picture of these additional controls?

 

[perart1]

 

[perart1]

I think that these two pictures illustrate the point that i am drawing peoples' attention to

 

[PrimaryControl]

First of all, I would like to thank flyer for the link to this blog entry and perart1 for his personal e-mail on this topic.

To simplify the topic, I would like to reduce the term "torque" to the radial force component and the resulting acceleration. A certain amount of force is required to set a mass in rotary motion. In the specific case of the Kinea Turntable, the platter has a mass which, viewed over the radius, is mainly located at the outer edge of the 35 cm diameter platter. The direct drive motor we use works with coreless air coils and can therefore be described as a low-torque motor. The direct drive turntables that were popular in the 1980s almost exclusively used iron core motors, which had a much higher torque. These motors had some characteristics that could have a negative effect on the sound (cogging). However, this is only mentioned here in passing.
An obvious task of a variable torque function is the start-up of the turntable. The higher the force component here, the higher the acceleration of the platter. By using an air-coil motor, it was clear that we needed a high torque to start rotating the platter. This shortens the acceleration time to achieve the desired speed. I think up to this point we all agree on the sense of a variable torque function of the drive.

In the second part of this entry, however, an unpredictable aspect of our beloved activity comes into play. That of the listener.
What we quickly realized during the development of the motor control was the subtle influence of the motor's drive current on the sound. A legitimate question here is, is there not an optimum setting for the drive current and the resulting torque?
From our point of view, the answer is yes and no.
For an individual listener, this setting can perhaps be found quickly, but does this apply to every potential listener? We have carried out extensive listening tests with audiophiles and musicians (or both in one person).
In doing so, we found that the preferences differed significantly in some cases. This realization was the starting point for the decision to equip the motor control with a variable torque. In order to limit the options somewhat, we decided on three settings. Mid-torque, so to speak, is the setting that we as the manufacturer consider to be the most universal for most music styles. Low and high torque as the two most opposite to the middle value.
Nevertheless, the differences of the one are rather subtle, but significant enough not to want to withhold them from the user of the Kinea Turntable.

If a more technical treatment of this topic is desired, I can go into it in a later entry.

 

[perart1]

First of all, I would like to thank flyer for the link to this blog entry and perart1 for his personal e-mail on this topic.

To simplify the topic, I would like to reduce the term "torque" to the radial force component and the resulting acceleration. A certain amount of force is required to set a mass in rotary motion. In the specific case of the Kinea Turntable, the platter has a mass which, viewed over the radius, is mainly located at the outer edge of the 35 cm diameter platter. The direct drive motor we use works with coreless air coils and can therefore be described as a low-torque motor. The direct drive turntables that were popular in the 1980s almost exclusively used iron core motors, which had a much higher torque. These motors had some characteristics that could have a negative effect on the sound (cogging). However, this is only mentioned here in passing.
An obvious task of a variable torque function is the start-up of the turntable. The higher the force component here, the higher the acceleration of the platter. By using an air-coil motor, it was clear that we needed a high torque to start rotating the platter. This shortens the acceleration time to achieve the desired speed. I think up to this point we all agree on the sense of a variable torque function of the drive.

In the second part of this entry, however, an unpredictable aspect of our beloved activity comes into play. That of the listener.
What we quickly realized during the development of the motor control was the subtle influence of the motor's drive current on the sound. A legitimate question here is, is there not an optimum setting for the drive current and the resulting torque?
From our point of view, the answer is yes and no.
For an individual listener, this setting can perhaps be found quickly, but does this apply to every potential listener? We have carried out extensive listening tests with audiophiles and musicians (or both in one person).
In doing so, we found that the preferences differed significantly in some cases. This realization was the starting point for the decision to equip the motor control with a variable torque. In order to limit the options somewhat, we decided on three settings. Mid-torque, so to speak, is the setting that we as the manufacturer consider to be the most universal for most music styles. Low and high torque as the two most opposite to the middle value.
Nevertheless, the differences of the one are rather subtle, but significant enough not to want to withhold them from the user of the Kinea Turntable.

If a more technical treatment of this topic is desired, I can go into it in a later entry.

Thank you so much for responding to my public and personal query so promptly. It's great to have the manufacturer give his point of view and reasons for what he does. Thank you

 

[Another Johnson]

OK...so I am contemplating adding another turntable and have narrowed it down to either of the above.
My first question is regarding the TechDas V . On the recent Premium version there are two additional pitch controls compared to the previous one. I assume that these vary the torque. None of the comments on the Premium mention them! Can anyone confirm this and clarify the effect this has on the records being played.

Well, I’m glad you got an answer from the company. But I’m sure you would still like someone to chime in with what they hear.

But that’s not the reason I posted again. I visited the TechDAS site and read their better than average write up. They clearly state that the actual speed setting is precisely tied to the oscillator. This is a common approach for turntable drives that are synched to an oscillator. Torque is varied to deal with acceleration from 0, or between speeds. It is not part of the steady state speed control strategy.

 

[PrimaryControl]

Torque is varied to deal with acceleration from 0, or between speeds. It is not part of the steady state speed control strategy.

To make sure that there is no confusion here.
Variable torque in our application means that the user can choose between different values of the drive current. This current value remains the same to maintain the set speed. It therefore has more to do with how 'hard' the control intervenes.

 

[Another Johnson]

To make sure that there is no confusion here.
Variable torque in our application means that the user can choose between different values of the drive current. This current value remains the same to maintain the set speed. It therefore has more to do with how 'hard' the control intervenes.

I was referring specifically to the TechDAS write up for their own product.
You appear to be explaining this different, original feature of your product. As you point out, why deny the end user this additional chance to tune? I agree.

 

[perart1]

Well, I’m glad you got an answer from the company. But I’m sure you would still like someone to chime in with what they hear.

But that’s not the reason I posted again. I visited the TechDAS site and read their better than average write up. They clearly state that the actual speed setting is precisely tied to the oscillator. This is a common approach for turntable drives that are synched to an oscillator. Torque is varied to deal with acceleration from 0, or between speeds. It is not part of the steady state speed control strategy.

Yes..thanks. I have had a good look at the Techies site and yes the pitch control is exactly that by varying the speed of the platter. Not really sure it is much of an advantage as I would probably never use that facility. So the only differentiator for me between the old and the new is is that it is machined out of a single aluminium billet!

 

[skinnyfla]

Yes..thanks. I have had a good look at the Techies site and yes the pitch control is exactly that by varying the speed of the platter. Not really sure it is much of an advantage as I would probably never use that facility. So the only differentiator for me between the old and the new is is that it is machined out of a single aluminium billet!

… interested in this as I also habe these two on my list of potential new TTs…

 

[skinnyfla]

First of all, I would like to thank flyer for the link to this blog entry and perart1 for his personal e-mail on this topic.

To simplify the topic, I would like to reduce the term "torque" to the radial force component and the resulting acceleration. A certain amount of force is required to set a mass in rotary motion. In the specific case of the Kinea Turntable, the platter has a mass which, viewed over the radius, is mainly located at the outer edge of the 35 cm diameter platter. The direct drive motor we use works with coreless air coils and can therefore be described as a low-torque motor. The direct drive turntables that were popular in the 1980s almost exclusively used iron core motors, which had a much higher torque. These motors had some characteristics that could have a negative effect on the sound (cogging). However, this is only mentioned here in passing.
An obvious task of a variable torque function is the start-up of the turntable. The higher the force component here, the higher the acceleration of the platter. By using an air-coil motor, it was clear that we needed a high torque to start rotating the platter. This shortens the acceleration time to achieve the desired speed. I think up to this point we all agree on the sense of a variable torque function of the drive.

In the second part of this entry, however, an unpredictable aspect of our beloved activity comes into play. That of the listener.
What we quickly realized during the development of the motor control was the subtle influence of the motor's drive current on the sound. A legitimate question here is, is there not an optimum setting for the drive current and the resulting torque?
From our point of view, the answer is yes and no.
For an individual listener, this setting can perhaps be found quickly, but does this apply to every potential listener? We have carried out extensive listening tests with audiophiles and musicians (or both in one person).
In doing so, we found that the preferences differed significantly in some cases. This realization was the starting point for the decision to equip the motor control with a variable torque. In order to limit the options somewhat, we decided on three settings. Mid-torque, so to speak, is the setting that we as the manufacturer consider to be the most universal for most music styles. Low and high torque as the two most opposite to the middle value.
Nevertheless, the differences of the one are rather subtle, but significant enough not to want to withhold them from the user of the Kinea Turntable.

If a more technical treatment of this topic is desired, I can go into it in a later entry.

… I live in Germany but very close to the Dutch border (by Essen)… any suggestions as to where I could check out your Kinea?