FS: KAB RF-1 Rumble Filter
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miner
Posts: 1,305
I have used this accessory for approx. 3 yrs. Recent sale of phono stage heeds this KAB RF-1 useless to me. It served me well filtering out lower freq that caused issues not only with pumping woofers but also with acoustic feedback to your turntable.
From website:
Getting into LP's and startled at the big speaker cone movements that you're seeing? Thinking a better turntable will help? It may not! This very low frequency energy is called rumble. Much of it is actually cut into the record groove when the master disc was made. But the main source is feedback exciting the natural stylus/arm resonance between 7 and 12 hz. This produces a slow easily visible in and out motion of your woofers. If you cannot see this motion, the RF-1 will not solve your feedback problem. If you can see this motion, the RF-1 will solve your feedback problem.
And with rumble eliminated, the soundstage becomes more "still" and the bass actually tightens up because the woofers are no longer modulating and the power amp is no longer wasting current resources on sub audible noise.
The KAB Great Sound Escort RF-1 is a very fine transparent rumble filter that not only suppresses very low frequency (subsonic) energy, but also uses a unique active cancellation circuit that effectively suppresses vertical rumble too. Your subwoofers will thank you! Suppresses acoustic feedback too.
The RF-1 is a must for vinyl enthusiasts, live DJ's and when burning CD's for the car. You probably can't hear it, but your car woofers are going mad with all that subsonic rumble!
The KAB RF-1 is easy to install. Place it in between the phono preamp and control amp or in a process loop. It requires no attendance. It is happy to remain powered up at all times.
$120 shipped - fees covered. I can supply a set of cables also for addition charge to be determined.
__________________
From website:
Getting into LP's and startled at the big speaker cone movements that you're seeing? Thinking a better turntable will help? It may not! This very low frequency energy is called rumble. Much of it is actually cut into the record groove when the master disc was made. But the main source is feedback exciting the natural stylus/arm resonance between 7 and 12 hz. This produces a slow easily visible in and out motion of your woofers. If you cannot see this motion, the RF-1 will not solve your feedback problem. If you can see this motion, the RF-1 will solve your feedback problem.
And with rumble eliminated, the soundstage becomes more "still" and the bass actually tightens up because the woofers are no longer modulating and the power amp is no longer wasting current resources on sub audible noise.
The KAB Great Sound Escort RF-1 is a very fine transparent rumble filter that not only suppresses very low frequency (subsonic) energy, but also uses a unique active cancellation circuit that effectively suppresses vertical rumble too. Your subwoofers will thank you! Suppresses acoustic feedback too.
The RF-1 is a must for vinyl enthusiasts, live DJ's and when burning CD's for the car. You probably can't hear it, but your car woofers are going mad with all that subsonic rumble!
The KAB RF-1 is easy to install. Place it in between the phono preamp and control amp or in a process loop. It requires no attendance. It is happy to remain powered up at all times.
$120 shipped - fees covered. I can supply a set of cables also for addition charge to be determined.
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