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    Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

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    Bob Latino
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    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by Bob Latino on Tue Jul 27, 2010 6:24 pm

    This is my downstairs system. I use two Dynaco ST-120's biamped to drive the two Magnepan 3.6R's. The rest of the system is a BAT VK30SE preamp and a Classe CD transport into a Bel Canto DAC2. I also have a Bryston 4BSST amp below that I sometimes use in place of the two ST-120's. The Bryston has more power (500 WPC into 4 ohms) but the two ST-120 hold their own at lower volume levels and IMHO sound more musical than the SS Bryston amp. The vinyl rig is a Music Hall 7 turntable with a Goldring MC cartridge.

    My only regret with this system is because of the layout of the room I have to place the speakers on the shorter (12 foot wide) wall. The speakers are only about 8 feet apart on center. The speakers are about 4 feet from the back wall and sound treatment has been added to the rear and side walls to absorb reflections.

    Bob



    DesignInc

    Posts : 10
    Join date : 2010-08-31
    Age : 61
    Location : Central Coast, Calif

    Re: Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by DesignInc on Tue Aug 31, 2010 8:04 pm

    Ok ... got some power there Bob nice.

    Your magnepan's are SPL: 86 dB and my Allison One's are SPL: 88 dB so a bit more efficient.

    My question is: If you are running the speakers at let's say 12 watts/channel thru your Latino-Dynaco ST-70 w/ KT88's (where the amp is running very clean) and you could toggle to your Dynaco ST-120 (w/ same KT88's) adjusting down to the same volume as the the ST-70 would they sound the same or would the bigger amp sound better/different tone or what? Or would you only start to see the difference when the ST-70 get pushed closer to it's limit?

    thanks for the input!
    David

    Bob Latino
    Admin

    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by Bob Latino on Tue Aug 31, 2010 9:12 pm

    DesignInc wrote:Ok ... got some power there Bob nice.

    Your magnepan's are SPL: 86 dB and my Allison One's are SPL: 88 dB so a bit more efficient.

    My question is: If you are running the speakers at let's say 12 watts/channel thru your Latino-Dynaco ST-70 w/ KT88's (where the amp is running very clean) and you could toggle to your Dynaco ST-120 (w/ same KT88's) adjusting down to the same volume as the the ST-70 would they sound the same or would the bigger amp sound better/different tone or what? Or would you only start to see the difference when the ST-70 get pushed closer to it's limit?

    thanks for the input!
    David

    Hi David,

    Both the VTA ST-70 and ST-120 sound virtually identical. The ST-120 will, however, play about 3 dB louder with the same low distortion as the ST-70. When I played both the ST-70 and ST-120 for someone one time it appeared to him that the ST-120 "had more bass". In reality what was happening is that the the ST-120 had more HEADROOM at normal listening levels. As such, it had a greater ability to respond to musical peaks due to the its greater headroom and somewhat larger DC power storage than the ST-70. The ST-70 has about 504 uF of DC power storage. The ST-120 has about about 670 uF. The ST-70 is rated at 35 WPC while the ST-120, although rated at 60 WPC, will do 70 - 75 WPC over most of the audio range.

    To answer your last question .. The answer is yes - You will only really notice the difference between the two amps when the ST-70 is pushed near its limits ..

    Bob

    DesignInc

    Posts : 10
    Join date : 2010-08-31
    Age : 61
    Location : Central Coast, Calif

    Re: Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by DesignInc on Wed Sep 01, 2010 1:34 pm

    Thanks Bob

    That really does clarify the whole thing for me. I did notice yesterday that when I had my old Kenwood KR-6050 SS with 60rms wpc that when the receivers meters where steady at 10 wpc the meter would bounce close to 50wpc at peaks.

    When I think about it logically (which I do once in a while) the extra $180. is cheap if I think of it would extend the quality of sound for every minute and maybe the life span of my Allison Acoustic One's which are really quite valuable to me and driving 4-10" woofers, 4-mids and 4 tweeters can't be any to easy.

    I'm starting the cash jar today!
    thanks again,
    David

    Bob Latino
    Admin

    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by Bob Latino on Wed Sep 01, 2010 2:09 pm

    DesignInc wrote:Thanks Bob

    That really does clarify the whole thing for me. I did notice yesterday that when I had my old Kenwood KR-6050 SS with 60rms wpc that when the receivers meters where steady at 10 wpc the meter would bounce close to 50wpc at peaks.

    When I think about it logically (which I do once in a while) the extra $180. is cheap if I think of it would extend the quality of sound for every minute and maybe the life span of my Allison Acoustic One's which are really quite valuable to me and driving 4-10" woofers, 4-mids and 4 tweeters can't be any to easy.

    I'm starting the cash jar today!
    thanks again,
    David

    David,

    A very good point that many audiophiles don't fully understand. Even though your amp may be running at 5 or 6 watts continuous, the power required to "handle the peak" may be 5 or 10 times the steady state power. A larger amp will have more in its "reserve tank" and will always have the ability to respond to musical peaks more gracefully than a smaller amp.

    Bob

    boycephoto

    Posts : 5
    Join date : 2009-08-15

    System Question

    Post by boycephoto on Sun Sep 12, 2010 10:53 pm

    Hi Bob,

    What crossover are you using to bi-amp your Maggie 3.6's?

    Thanks
    Dave

    Bob Latino
    Admin

    Posts : 2413
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Two Dynaco ST-120's biamping a pair of Magnepan 3.6R's

    Post by Bob Latino on Mon Sep 13, 2010 7:19 am

    boycephoto wrote:Hi Bob,

    What crossover are you using to bi-amp your Maggie 3.6's?

    Thanks
    Dave

    Hi David,

    Just the crossover in the speaker .. 60 watts to the woofer/midrange panels and 60 watts to the upper ribbon tweeter panel.

    Bob

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