Herzan/Table Stable "Active" Isolation table.

[rockitman]

Any resonant suspension would be a potential problem due to a possibility of beat oscillations if the natural frequencies are too close. However with pneumatics one can control the natural frequencies by the air pressure so it may be possible to find such a combination of pressures in the AF1 suspension and the underlying pneumatic platform that the two suspensions cooperate rather than excite each other. Experimentation is needed.

Cheers,

That's interesting and makes sense for those willing to experiment.

 

[Stacore]

That's interesting and makes sense for those willing to experiment.

If anyone wants to experiment with AF1 and our platforms, I offer free shipping anywhere in the world
Cheers,

 

[rockitman]

If anyone wants to experiment with AF1 and our platforms, I offer free shipping anywhere in the world
Cheers,

That is good to know Jarek. Once I'm settled in my new place next year and the rest of the system is sorted, I will visit AF1 supplemental isolation.

 

[Stacore]

That is good to know Jarek. Once I'm settled in my new place next year and the rest of the system is sorted, I will visit AF1 supplemental isolation.

Sure Christian, would be interesting to see if we can improve the performance.
Cheers,

 

[microstrip]

(...)

Active isolation
Active vibration isolation systems contain, along with the spring, a feedback circuit which consists of a sensor (for example a piezoelectric accelerometer or a geophone), a controller, and an actuator. The acceleration (vibration) signal is processed by a control circuit and amplifier. Then it feeds the electromagnetic actuator, which amplifies the signal. As a result of such a feedback system, a considerably stronger suppression of vibrations is achieved compared to ordinary damping. (...)

IMHO it is the Achilles knee of such systems from an audiophile perspective. It is a feedback system, and errors are electronically corrected to very low values, leaving an history behind the correction. I can easily imagine that people who object to feedback in turntable motors will not feel happy having feedback in the platform ... .

BTW, I know that my Studer A80 capstan motor - by far my best analog audio source - has a feedback system. As a consequence I can not be against feedback and trying an active table in my system is written somewhere in my wish list, but only after I stabilize my system.

 

[rockitman]

New vid of NDW-23 actively isolating spinning non suspended TT. Solid yellow enable light and no red lights means the system is isolating correctly. Any flickering red lights indicate some instability somewhere in the system and or a load imbalance. I can’t wait for the Hammer to arrive.
https://youtu.be/V0wUt1SIB7k

 

[ddk]

Hi Taiko,

Hi David,

Well its achieving a certain level of isolation through damping, amongst others

Just following instructions !

Isolation is of course not equivalent to damping. You would call the tablestable and isolating device, but it isn't, it is dissipating vibrational energy by producing a counter force.

david

 

[dminches]

The video is saying it is blocked for copyright content.

 

[rockitman]

The video is saying it is blocked for copyright content.

I don't see that. Hmmmm

 

[Mike Lavigne]

I don't see that. Hmmmm

if music is playing, it reads that sound as protected content; and won't allow open distribution. same way phone apps can figure out which CD it is.

 

[rockitman]

if music is playing, it reads that sound as protected content; and won't allow open distribution. same way phone apps can figure out which CD it is.

so you can't see it either ?

 

[rockitman]

so you can't see it either ?

well I am having a little lesson in youtube today, Hendrix astro man is copyrighted...

 

[dminches]

well I am having a little lesson in youtube today, Hendrix astro man is copyrighted...

Do you have a Grateful Dead bootleg album? That shouldn't be detected!

 

[rockitman]

Do you have a Grateful Dead bootleg album? That shouldn't be detected!

I will have to watch that copyright stuff. I could play some old classical 1958-1961 where there is no more copyright.
That was an obscure cut of the song from Hendrix's recent 8 record box set pressed at Quality Records.

 

[Taiko Audio]

Hi Taiko,



Just following instructions !



david

Ah yes I see where that went wrong! It should read this:
"Isolation is of course not equivalent to damping. You would call the tablestable a damping device, but it isn't, it is dissipating vibrational energy by producing a counter force."

Now this is in fact out of context as a single statement, as the isolation the tablestable provides is by means of A) destructive interference that cancels-out incoming vibrations for lower frequencies, the active isolation, but it also provides passive isolation by means of (spring) damping. If you disable the active isolation it would be a strictly passive isolating device by a mass/spring damping principle.

The corrected sentence above strictly applies to the active isolation mechanism of the tablestable.

 

[ddk]

Ah yes I see where that went wrong! It should read this:
"Isolation is of course not equivalent to damping. You would call the tablestable a damping device, but it isn't, it is dissipating vibrational energy by producing a counter force."

Now this is in fact out of context as a single statement, as the isolation the tablestable provides is by means of A) destructive interference that cancels-out incoming vibrations for lower frequencies, the active isolation, but it also provides passive isolation by means of (spring) damping. If you disable the active isolation it would be a strictly passive isolating device by a mass/spring damping principle.

The corrected sentence above strictly applies to the active isolation mechanism of the tablestable.

Ok . So the active part is reacting to vibrations it senses from the top plate?

david

 

[rockitman]

Here’s another vid. Used Shure MV88 into iPhone. Let’s see if the central scrutinizer busts me for this 1960 classical content.
https://youtu.be/_KlMAjdYp9A

 

[Taiko Audio]

Ok . So the active part is reacting to vibrations it senses from the top plate?

david

Most of the electronics including sensors are attached to the topplate but my understanding is there are also sensors mounted in the bottom structure.

 

[microstrip]

(...) Now this is in fact out of context as a single statement, as the isolation the tablestable provides is by means of A) destructive interference that cancels-out incoming vibrations for lower frequencies, the active isolation, but it also provides passive isolation by means of (spring) damping. If you disable the active isolation it would be a strictly passive isolating device by a mass/spring damping principle.

The corrected sentence above strictly applies to the active isolation mechanism of the tablestable.

Although this mechanism can be used in some noise cancelling devices - they have a sensor outside the isolated volume and drive this volume with an out of phase signal created from the signal generated by this sensor, I am not sure that a similar technique is used in laboratory active tables - I had got the idea that the system is much more sophisticated than just destructive interference, particularly because the fixed part of the table is not an inertial reference. Do you know if there are any sensors in the upper part of the table?

The best AFM (atomic force microscope) tables combine passive pneumatic and active piezoelectric - but surely at a much higher price!

 

[Taiko Audio]

Although this mechanism can be used in some noise cancelling devices - they have a sensor outside the isolated volume and drive this volume with an out of phase signal created from the signal generated by this sensor, I am not sure that a similar technique is used in laboratory active tables - I had got the idea that the system is much more sophisticated than just destructive interference, particularly because the fixed part of the table is not an inertial reference. Do you know if there are any sensors in the upper part of the table?

The best AFM (atomic force microscope) tables combine passive pneumatic and active piezoelectric - but surely at a much higher price!

Ok, I'll admit to having disassembled a TS-150 in a very early stage, out of curiosity, which is something nobody should do as I ended up having to return it to the factory for recalibration Without specifically focusing on this particular subject, I was more interested in the motor assemblies at that time, I did count at least 12 sensors, it's quite possible there are more, they are located on both the top plate and bottom structure. Which sensor serves which function I do not know and did not investigate.