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    VTA ST-120 and new Magnepan 1.7i

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    ImFritz

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    Post by ImFritz on Fri Apr 05, 2019 4:37 pm

    So far right out of the box the Maggies are sounding pretty dang sweet. They sound so clean that I find myself wanting to turn up the attenuator on my ST-120.
    Nice combo. Have been contemplating getting another ST-120 for bi amping them. One for each channel. For now my question is this. How far can I push the VTA ST-120. Right now i'm at about the 4 o'clock position on the attenuator knob. How do I know Im pushing to hard? Does not sound like i'm clipping at all.
    Any comments welcome.
    Thanks Very Happy
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    ImFritz

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    Post by ImFritz on Sat Apr 06, 2019 11:48 am

    Wow,
    78 views and no one can comment? I know Im new to tubes... Just asking
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    audiobill

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    Location : Albany, NY

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    Post by audiobill on Sat Apr 06, 2019 12:28 pm

    Hi Fritz, if yhe sound is clean, no worries you're pushing too hard. The ST-120 is a robust amp that can drive your 1.7s just fine to rather high levels.

    Congrats and enjoy!!
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    ImFritz

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    Post by ImFritz on Sat Apr 06, 2019 1:55 pm

    Thank you Bill! Cool
    Peter W.
    Peter W.

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    Post by Peter W. on Mon Apr 08, 2019 7:51 am

    Sorry for the late response - we indulge in "Amish Weekends" for our sanity. A remarkably refreshing break from being 'connected'.

    If you have an attenuator on the amp, that is substantially different from what is on the typical active pre-amp. Without getting into a bunch of details, you are not likely to go into clipping at any volume via that attenuator. Not impossible, just not likely.

    Then, tube amps clip softly. You may not notice clipping at the margins - the best way I might describe it would be as if the amp were 'breathing'.

    Bi-Amping with another 120 would be an excellent response to those marginal issues. And Maggies are particularly suitable for bi-amping given their flat impedance curve.

    I keep MG-111s, and in a very large room. So I have a very large solid-state amp to provide the headroom and transient response needed in that room.

    Enjoy!
    jsl1234
    jsl1234

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    Post by jsl1234 on Mon Apr 08, 2019 2:32 pm

    Just a quick question-can you run VTA 120s in mono bridged mode? Isn't that the reason for the VTA M125?
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    ImFritz

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    Post by ImFritz on Mon Apr 08, 2019 4:51 pm

    Peter W. wrote:Sorry for the late response - we indulge in "Amish Weekends" for our sanity. A remarkably refreshing break from being 'connected'.

    If you have an attenuator on the amp, that is substantially different from what is on the typical active pre-amp. Without getting into a bunch of details,  you are not likely to go into clipping at any volume via that attenuator. Not impossible, just not likely.

    Then, tube amps clip softly. You may not notice clipping at the margins - the best way I might describe it would be as if the amp were 'breathing'.

    Bi-Amping with another 120 would be an excellent response to those marginal issues. And Maggies are particularly suitable for bi-amping given their flat impedance curve.

    I keep MG-111s, and in a very large room. So I have a very large solid-state amp to provide the headroom and transient response needed in that room.

    Enjoy!

    Thanks Peter Very Happy
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    New2Tubez

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    Join date : 2018-03-20
    Location : NY

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    Post by New2Tubez on Mon Apr 08, 2019 10:46 pm

    ImFritz wrote:Wow,
    78 views and no one can comment? I know Im new to tubes... Just asking

    No, I'm New2Tubez...; ]
    Bob Latino
    Bob Latino
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    Post by Bob Latino on Tue Apr 09, 2019 9:34 am

    jsl1234 wrote:Just a quick question-can you run VTA 120s in mono bridged mode? Isn't that the reason for the VTA M125?

    You can bridge the ST-120 but the amp does not sound as good if you do that. What you should do to use two VTA ST-120's to drive a pair of Magnepan's is to biamp vertically with one amp on each stereo channel. You use one of the ST-120 channels on the woofer panel and the other ST-120 on the tweeter section. You then do the same thing with the other ST-120 on the other stereo channel. It works well and I have done this before on the Magnepan 3.6R's that I have here on my downstairs system. Below is a photo of two ST-120's driving my Maggies. One ST-120 amp was mine and one was a customers. I now use two M-125's in place of the two ST-120's.

    Bob

    VTA ST-120 and new Magnepan 1.7i Biamping-a-pair-of-Magnepan-3-6
    jsl1234
    jsl1234

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    Post by jsl1234 on Tue Apr 09, 2019 10:15 am

    That’s why I’m asking—didn’t think the newer Maggie’s 7 series could be bi-amped, ie not sure you can drive the tweeter and woofer panel separately on the newer Maggie’s (3.7, 1.7, .7 etc).
    Peter W.
    Peter W.

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    Post by Peter W. on Tue Apr 09, 2019 10:28 am

    Just one little thing:

    Using any two-channel amp for single-side (vertical) bi-amping has a significant drawback against a single more powerful amp:

    a) A 60-per-side amp will deliver _ONLY_ 60 watts to either section.
    b) A single 120 watt amp will 'deliver' as the signal requires such that the load may not be evenly divided. That, for the record, is a good thing.

    Making the 125 a better option than a strapped 120, or event two vertical 120s.
    jsl1234
    jsl1234

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    Post by jsl1234 on Tue Apr 09, 2019 10:45 am

    Agree, my .02 is a mono amp per side is the only practical configuration when you don’t have a discrete active crossover in the path for the speakers in question (and it can be properly interfaced directly to the drivers without going through the legacy crossover, which is usually designed for optimal effect as wired). Regardless of my .02, out of the box bi-wire or bi-amp configurations with two stereo amps for newer Maggie’s is not possible since the crossover is embedded and you’d have to be willing to break open the back panel and rewire/reconfigure the passive crossover.

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