Seismion Reactio 有新VIDEO呀

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The quality improvement of turntables using Seismion Reactio

Turntables are known to be extremely sensitive towards any mechanical vibrations. The needle of the pickup reacts to the smallest information in the record groove and translates it into tiny movements. They are converted into small current fluctuations that are further amplified in the phono preamplifier.
However, the needle is also prone to external vibrations, which are in the same way amplified and fed into the audio system. These parasitic vibrations can either originate from ambient vibrations that transfer mechanically through the base into the turntable. Another source of disturbance is the music itself. The loudspeaker introduc sonic waves that excite everything in the room including the turntable. This feedback loop introduces also a phase shift, which depends on the frequency as well as the distance between loudspeaker and turntable. Combined with the desired vibrations from the record groove it leads to a distortion.

There is no way to distinguish between the desired vibrations from record groove and unwanted parasitic vibrations. As these parasitic vibrations are generated at the very first stage of the chain and multiple times amplified in the following, they are especially unwanted. Therefore, a turntable is a good application to show the impact of active vibration isolation upon its performance.

To study only the influence of ambient, undesired vibrations, we use the turntable with a still-standing motor (no music). The turntable is connected to a phono amplifier, and the output is shown on an oscilloscope. This can be regarded as a noise floor measurement, since the signal is only due to the noise in the system and ambient vibrations.

The turntable used for this test is Thorens TD160 MK II with modified pickup and a phono amplifier with discrete differential bipolar input stage (equivalent input noise less than 1 nV/Hz^0.5) and OPA 627 equivalent OPs.

The turntable is placed on our Seismion Reactio, and the whole setup is standing on a rather rigid optical table. The overall parasitic vibrations are small, as you would look for when placing high-quality audio devices. During the whole video, the system is excited by slight footfall.

At the beginning of the video, the vibration isolator is turned off, and after some time turned on. This can be seen on the LED that changes from red to green. At the very end, the needle is lifted up.

The video shows in realtime the output signal from the phono amplifier. The improvement by active control is obvious, as the remaining signal is hardly visible and some orders lower than without active control. The influence of normal footfall is too small to be recognized in the signal, therefore the excitation is even increased when the isolator is turned on. Still, only a very small disturbance can be seen in the voltage signal.

This video proves that the Seismion Reactio can handle both very small and signicantly larger disturbances, and leads to a very clean signal with only very little parasitic influences. Without showing in this video, we can assume the active vibration isolator is equally helpful to reduce distortions due to sonic feedback.

All types of turntables, even in the high-end range, should benefit a lot from the active control.







[團購] 德國SEISMION "REACTIO" 零震台

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