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  1. #1
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    X150.8 front meter dancing around…

    When I was speaking to a Pass technician, he mentioned in passing that when the meter starts dancing, the amp is close to running out of power.

    I find that at an average of 84 db SPL with peaks at 92-95 db, my meter is already dancing with movements of 2 to 4 mm.

    Do you think I need to upgrade my amp for more power? On some songs, I think I hear a little distortion (You Got Me by The Roots), but am not sure. It could be the recording.

    Speaker is a Zu Omen Def MkII. Its a pretty load, flattish at 8 ohms, 96 db -ish (103 db published). Streaming to an Allnic preamp which has really improved my bass response vs a BAT previously.

    Would appreciate feedback.

  2. #2
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    Re: X150.8 front meter dancing around…

    I wouldn't call 2mm 'dancing around', more like a slow waltz .....
    Cheers ! …. Dave

  3. #3
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    Re: X150.8 front meter dancing around…

    Quote Originally Posted by Mikado463 View Post
    I wouldn't call 2mm 'dancing around', more like a slow waltz .....
    My history with the amp is the meter doesnt move at all.

  4. #4
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    Re: X150.8 front meter dancing around…

    From what I understand the needle is stationary when the amplifier is operating in class A mode. When the needle moves, it indicates class AB operation. I think the 150 leaves Class A at 15 watts. This said, I would call Kent at Pass to be sure ...
    Sincerely,

    Calvin

  5. #5
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    Re: X150.8 front meter dancing around…

    Even leaving Class A wih the Zu you have to be much louder than 84dB unless your listening room is an auditorium. With that being said some Zu are 16 ohms and if that's your case it will limit the power output to less than stated power.

    I had some Zu Soul Super Fly and drove them with Conrad Johnson 100 watt monoblocks and they never stressed. A X150.8 into 96dB speakers should be enough to cause deafening SPL's.

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  6. #6
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    Re: X150.8 front meter dancing around…

    Quote Originally Posted by Mr Peabody View Post
    Even leaving Class A wih the Zu you have to be much louder than 84dB unless your listening room is an auditorium. With that being said some Zu are 16 ohms and if that's your case it will limit the power output to less than stated power.

    I had some Zu Soul Super Fly and drove them with Conrad Johnson 100 watt monoblocks and they never stressed. A X150.8 into 96dB speakers should be enough to cause deafening SPL's.

    Welcome to AS
    The Zu Omen Defs are actually 8 ohms.

    I completely understand what youre saying, however its not the case here. The amp meter starts to move, which I am assuming at this point, thats its leaving Class A, just when Im at my desired listening level. Its not super loud at all, but the bass is pretty serious.

  7. #7
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    Re: X150.8 front meter dancing around…

    I just got off the phone with a tech at Pass Labs and he confirmed that the meter dancing around means “Ive left Class A” and am in the A/B section.

    The meter would be signaling Im running out of juice if it were pegging the right side.

    That makes sense, though I stressed this amp with a Magnepan 1.7i and never saw it peg to the right.

  8. #8
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    Re: X150.8 front meter dancing around…

    I really like the people at ZU & their products.

    However, IME, all of the ZUs were somewhat less efficient than their specs claimed, when compared to other competitive lines/products and their specs...

    But they could be sooo musically involving...
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  9. #9
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    Re: X150.8 front meter dancing around…

    Quote Originally Posted by Jim Smith View Post
    I really like the people at ZU & their products.

    However, IME, all of the ZUs were somewhat less efficient than their specs claimed, when compared to other competitive lines/products and their specs...

    But they could be sooo musically involving...
    I agree. The only company whose Sensitivity rating I feel I would trust at face value is Devore. Its not really a matter of honesty, just the effort and resources they put into it.

  10. #10
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    Re: X150.8 front meter dancing around…

    Still if the Maggies didn't stress the 150.8 the Zu shouldn't even if a bit less than rated efficiency. Zu is driven by SET owners so shouldn't be an issue for your amp

    I wonder if the Omen maybe wired incorrectly and impedance dipping very low.

    I feel there is an issue with a component or connection in your system. What you are experiencing is not normal.
    Aurender ACS10 w/Audioquest Diamond USB,
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  11. #11
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    Re: X150.8 front meter dancing around…

    Quote Originally Posted by Mr Peabody View Post
    Still if the Maggies didn't stress the 150.8 the Zu shouldn't even if a bit less than rated efficiency. Zu is driven by SET owners so shouldn't be an issue for your amp

    I wonder if the Omen maybe wired incorrectly and impedance dipping very low.

    I feel there is an issue with a component or connection in your system. What you are experiencing is not normal.
    Sorry if I didnt mention it clearer. The Pass amp meter didnt fully peg to the right with the Maggies, but it was stressing. Popcorn bass for one at medium SPL.

    Zu sound excellent. No problem with them. I am just a little surprised that as you say, they can be driven by 3 watt SET amps, but they shine with the Pass amp. I just didnt understand what the meter is saying. Now I do, but still not completely per my Maggie experience.

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