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    Step Attenuator vs pre-amp

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    dacer38

    Posts : 6
    Join date : 2015-09-04
    Location : Lakehills Texas

    Step Attenuator vs pre-amp

    Post by dacer38 on Fri Sep 11, 2015 10:17 am

    I know this is kind of an open ended question. What are the benefits and cost of each? Seems for my application the attenuator is the way to go. Have two sources, DAC and TT so it's and easy switch between sources.

    Bob Latino
    Admin

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    Join date : 2008-11-26
    Location : Massachusetts

    Re: Step Attenuator vs pre-amp

    Post by Bob Latino on Fri Sep 11, 2015 10:46 am

    dacer38 wrote:I know this is kind of an open ended question. What are the benefits and cost of each? Seems for my application the attenuator is the way to go. Have two sources, DAC and TT so it's and easy switch between sources.

    The stepped attenuator removes the preamp from the audio chain and some like the direct connection to the amp. If you are using and older Dynaco PAS-2/3 preamp in your system the sound quality will definitely be better without the preamp in the audio chain. With more modern high quality preamps such as the VTA SP preamps, any increase in sound quality will be neglible using the stepped attenuator. If you have two signal sources and are willing to swap cables and/or use some type of switch box for switching signal sources, the stepped attenuator may be a good choice.

    Just to be clear > You can also (at a later date) use the amp with a preamp with the attenuator still in place. If you turn the attenuator all the way to the right, there is a pass through of the audio signal directly from the input jacks to the driver board input eyelets and the stepped attenuator is "out of the circuit" with just one extra solder connection in the way.

    Bob

    sKiZo

    Posts : 1310
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Step Attenuator vs pre-amp

    Post by sKiZo on Fri Sep 11, 2015 2:49 pm

    Yup ... in my custom build, I added two high quality old school Mallory pots instead. That gives me adjustable balance as well.



    Be a bit difficult to shoehorn something that big into the stock chassis, but I'm sure there's room for two ... if you don't mind burning up a couple bits trying to drill stainless steel.

    And yes ... I also use a pre AND a DAC, both with their own level controls, not to mention software volume for digital files, in the signal path. Gives me multiple options for matching the signal through the components and feed them exactly what they're most happy with. You'd be surprised how much difference that can make after a bit of tweaking and listening.

    nmchiefsfan

    Posts : 33
    Join date : 2012-03-21

    Re: Step Attenuator vs pre-amp

    Post by nmchiefsfan on Fri Sep 11, 2015 5:43 pm

    If by TT you mean turntable you will need some kind of phono pre between the turntable and the amp.

    Kentley

    Posts : 335
    Join date : 2015-03-06
    Age : 64
    Location : Worcester, MA

    Re: Step Attenuator vs pre-amp

    Post by Kentley on Fri Sep 11, 2015 5:55 pm

    I'm with sKiZo on using BOTH a pre and the attenuator. The variations of tone available are subtle but real. In my case, adjusting the ST-120 attenuator so that my SP-14 pre can work pretty hard (at 2 to 4 o'clock) gives the best overall tone for all types of source material. In other words, I'm using the attenuator MORE for adjustments than the pre level control.
    Comparison between using the pre with the attenuator and using the attenuator alone in my system, with my ears, yielded a dramatically different result. When levels are just right, the pre+attenuator sounds much richer and punchier. And rounder.

    pedrocols

    Posts : 63
    Join date : 2014-11-24
    Location : Western MA

    Re: Step Attenuator vs pre-amp

    Post by pedrocols on Sat Sep 12, 2015 2:05 pm

    I literally sold my 4,000 BAT preamp after trying a passive preamp.  The BAT preamp will give sort of a greater 3D effect. However, for what I paid for the passive preamp the difference to my ears was not a very profound one.


    Last edited by pedrocols on Sun Sep 13, 2015 12:27 am; edited 1 time in total

    Kentley

    Posts : 335
    Join date : 2015-03-06
    Age : 64
    Location : Worcester, MA

    Re: Step Attenuator vs pre-amp

    Post by Kentley on Sat Sep 12, 2015 10:40 pm

    pedrocols wrote:I literally sold my 4,000 BAT preamp after trying a passive preamp.  The BAT preamp will give sort of a greater 3D effect but for what I pay for a passive preamp the difference to my ears was not a very profound one.

    I think I may be able to shed some light on why some folkses find little difference between an active pre and a passive one (which is essentially an attenuator plus some switching capability). In my experience, acoustically recorded music ("classical", older jazz, and any music recorded in a "real" acoustic space) will benefit far more from the use of a good pre - such as the SP-14 - than electric music recorded in a studio, where a great deal of the ambience, soundstage, and imaging is produced electronically or even digitally. In other words, if you prefer Pink Floyd to Beethoven, you might find it worthwhile to save some denari and use the attenuator alone, or an inexpensive passive pre. Studio music, especially in the Digital Age, is heavily processed in ways we sometimes are scarcely aware of - manipulated to the point where no elaborate signal path can ever enhance it. Vinyl - well, yer gonna need a pre no matter what.
    Of course, as always, system synergy, room setup and treatment, and good ol' personal taste is gonna matter more than anything else......

    corndog71

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    Re: Step Attenuator vs pre-amp

    Post by corndog71 on Sun Sep 13, 2015 1:36 pm

    I've always found the trade-off to be a little better clarity from the attenuators vs. better dynamic swings and oomph from a good preamp. The latter wins for me.

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