| GREAT FEATURES
- 1 Year Warranty
- Gold Teflon
- Active Vertical
- Dual Voltage
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- Hi Current Power
The really great features to take note of
with the RF-1 are, I believe, the product uniqueness. You simply do not see the
rumble filters being offered anymore. Yet the need for these special devices is
One of the biggest let downs with phono
playback is subsonic rumble. Often part of the recording itself, even the best
turntable will reproduce it. And with todays cross over video and music
entertainment systems, response down to 10 Hz is common.
A good rumble
filter will actually improve the bass response by removing those deep subsonic
dynamic swings from the system altogether. The power amp breathes easier and
the woofers can concentrate on the music at hand.
Unique to vinyl records:
When records are made, frequencies below about 150Hz are combined to mono. This
is done to avoid large out of phase groove excursions.
2. When the stereo
stylus moves vertically, the two signals produced are equal and 180 degrees out
Therefore, below 140Hz, the music is in phase in the lateral
stylus motion, and only out of phase noise is found in the vertical stylus
The KAB RF-1 takes advantage of this by electronically combining
the left and right channels together below 140Hz. In so doing the filter
effectively cancels vertically modulated noise. Vertical rumble comes generally
from bearing noise of the disc cutting system. But since the music below 140hz
is already mono on the disc, the musical information is unaffected.
20Hz, all signals are quickly attenuated at 18dB/Octave.
The RF-1 follows the KAB tradition of true
single ended Polar Stable design. This technique operates the circuitry in a
constant state of preconditioning(often called Burn In). This ensures a very
consistent sound quality that never waivers.