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    KAB RUMBLE FILTER PAS3

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    daniel a

    Posts : 8
    Join date : 2013-12-26

    KAB RUMBLE FILTER PAS3

    Post by daniel a on Wed Dec 03, 2014 3:59 pm

    Is it possible to wire a KAB rumble filter between phono stage and line stage of a Dynaco PAS3 using the tape loop or is this buffered

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: KAB RUMBLE FILTER PAS3

    Post by deepee99 on Wed Dec 03, 2014 4:07 pm

    daniel a wrote:Is it possible to wire a KAB rumble filter between phono stage and line stage of a Dynaco PAS3 using the tape loop or is this buffered

    The KAB rumble filters go directly between the turntable and the phono inputs. No need for a loop.

    daniel a

    Posts : 8
    Join date : 2013-12-26

    Re: KAB RUMBLE FILTER PAS3

    Post by daniel a on Wed Dec 03, 2014 4:19 pm

    KAB RF1 mounts between phono preamp and control amp

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: KAB RUMBLE FILTER PAS3

    Post by deepee99 on Wed Dec 03, 2014 4:26 pm

    Daniel A
    I stand corrected. Been a long time since I used them (with great satisfaction, I might add). Please forgive the bum advice.
    Dunno why they wouldn't work through the tape/mon loop.



    daniel a

    Posts : 8
    Join date : 2013-12-26

    Re: KAB RUMBLE FILTER PAS3

    Post by daniel a on Wed Dec 03, 2014 4:37 pm

    I was concerned the tape loop on a PAS 3 was buffered and would affect sound quality. Have any knowledge?

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: KAB RUMBLE FILTER PAS3

    Post by deepee99 on Wed Dec 03, 2014 4:39 pm

    daniel a wrote:I was concerned the tape loop on a PAS 3  was buffered and would affect sound quality. Have any knowledge?

    Roy at tubes4hifi would know.

    peterh

    Posts : 680
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: KAB RUMBLE FILTER PAS3

    Post by peterh on Wed Dec 03, 2014 5:31 pm

    daniel a wrote:I was concerned the tape loop on a PAS 3  was buffered and would affect sound quality. Have any knowledge?
    the tapeloop on PAS3 is not buffered in any way That's one of the problems, any loading
    of the tape-out will affect loading on riaa .

    tubes4hifi
    Admin

    Posts : 1292
    Join date : 2008-11-30

    Re: KAB RUMBLE FILTER PAS3

    Post by tubes4hifi on Wed Dec 03, 2014 7:08 pm

    I looked at their website and there is near zero info, no mention of input or output impedance.
    It seems they do have a 15 day return policy (less 6% return and shipping) so the only way to know for sure would be to try it.
    The PAS3 phono is problematic because with only two tubes it has zero drive, high impedance, and the EQ will be totally screwed
    if it has a load of less than about 200K. Most solid state products (which the KAB is) have an input impedance around 5-10K,
    so most likely it will solve the bass problem but create a worse treble problem likely losing most of the signal above mid-range.
    If it weren't so expensive I'd buy one and test it myself with a sig gen and oscope (plus I don't have a PAS3 handy).
    For the price of their filter, you could buy a super nice solid state phono preamp with a built-in rumble filter.

    Or look at alternatives, such as this one for $20 . . .
    http://store.acousticsounds.com/d/60042/DB_Systems-DB_Systems_Subsonic_Filter-Turntable_Accessories

    I suspect that what KAB is selling is similar to this circuit which is about $25 worth of parts . . .
    http://sound.westhost.com/project99.htm

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: KAB RUMBLE FILTER PAS3

    Post by deepee99 on Wed Dec 03, 2014 11:01 pm

    tubes4hifi wrote:I looked at their website and there is near zero info, no mention of input or output impedance.
    It seems they do have a 15 day return policy (less 6% return and shipping) so the only way to know for sure would be to try it.
    The PAS3 phono is problematic because with only two tubes it has zero drive, high impedance, and the EQ will be totally screwed
    if it has a load of less than about 200K.   Most solid state products (which the KAB is) have an input impedance around 5-10K,
    so most likely it will solve the bass problem but create a worse treble problem likely losing most of the signal above mid-range.
    If it weren't so expensive I'd buy one and test it myself with a sig gen and oscope (plus I don't have a PAS3 handy).
    For the price of their filter, you could buy a super nice solid state phono preamp with a built-in rumble filter.

    Or look at alternatives, such as this one for $20 . . .
    http://store.acousticsounds.com/d/60042/DB_Systems-DB_Systems_Subsonic_Filter-Turntable_Accessories

    I suspect that what KAB is selling is similar to this circuit which is about $25 worth of parts . . .
    http://sound.westhost.com/project99.htm

    Roy, I have a pair that worked wonders until some needed additional carpentry to isolate the turntable rendered them unnecessary. I will mail them to you, try them out for a month or two for eval, then send 'em back, postage on you both ways. Set your turntable on top of a subwoof. Email me if interested. Keven's a straight-shooter. Trust me, they will not scramble the signal path.


    tubes4hifi
    Admin

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    Join date : 2008-11-30

    Re: KAB RUMBLE FILTER PAS3

    Post by tubes4hifi on Wed Dec 03, 2014 11:30 pm

    sounds good Dave, I can test them but don't have a PAS3 handy, but maybe I can fudge an old PAS3 phono stage together.
    I can definitely see how it affects EQ with a sig gen and oscope.

    deepee99

    Posts : 1337
    Join date : 2012-05-23
    Location : Wallace, Idaho

    Re: KAB RUMBLE FILTER PAS3

    Post by deepee99 on Wed Dec 03, 2014 11:37 pm

    On their way, gimme a day or two to get them boxed up, not very heavy.
    There's two, one for each channel.
    If you like them, and somebody else is having rumble/feedback issues, I would be pleased to put them into our lending library until somebody Bogarts them, in which I'll have to exact retribution.
    Maybe they're just a nickel's worth of parts, I dunno, haven't stripped them. Kevin told me the design is very old, used in tube recording gear back in the 1950s.

    PeterCapo

    Posts : 386
    Join date : 2008-12-05

    Re: KAB RUMBLE FILTER PAS3

    Post by PeterCapo on Tue Dec 23, 2014 6:24 pm

    Any developments? Interesting topic.

    Thanks!
    Peter

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