MC1.25KW - no ordinary amps, thank you McIntosh!

Discussion in 'McIntosh Audio' started by joeinid, Jan 2, 2018.

  1. Bill Ferris

    Bill Ferris Super Member

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    I understand joeinid, in my case the Mac XRT 30 speakers are not very efficient @ 87 DB SPL 1watt @ 1 meter !!

    So I noticed the AC line monitor dipped alarmingly low during strong impacts of dynamic music passages from DDD/SCAD CDs when the amps were plugged into my living room`s regular AC circuit and I thought the bass sounded some what mushy from what I thought it should sound like.
    I`m a retired FOH sound engineer and became used to live dynamic sound..
    So that helped guide me in my system setup.. IMG_0320.JPG
     
    Last edited: Jan 5, 2018
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  2. joeinid

    joeinid AK Subscriber Subscriber

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    Thank you Bill. Very impressive. I know it makes sense. Looks like an awesome setup you have.
     
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  3. Bill Ferris

    Bill Ferris Super Member

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    Thank you, most kind Sir.
    It took quite a few years and saved nickels to get there..
    With no wife or children helped make it a little more quicker to realize..
     
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  4. damacman

    damacman Blown and Injected Subscriber

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    You guys are nuts with these 1200 watt amps! Lol ...
     
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  5. Velocityboat

    Velocityboat Super Member

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    Joe,

    There is an argument to be made both ways. Unless you are sitting in the exact same seat or position frequencies on the high end of the spectrum can change level by moving your head a few inches and can be easily susceptible to room influences as is the bass Plus our sources can vary. So unless you are using headphones and playing same sources repetively one’s interpretation of changes of burn in changes could be room influences. Myself I have noticed music sounding different night to night. Which investigation is usually shown to be familial influences of wife moving speaker or furniture or changing listening positions of Room Perfect being unaware.

    That being said some capacicor types can change with burn in and speaker surrounds also change response by gaining flexibility with movement.


    I do think Room acoustics can fool us on what is good sound and changes we hear regarding being at room modes or being in s null at a listening position. That could be why one thinks sound changed by burn in or why two people in same room listening to same system have different opinions about highs or lows. It is the additive room effects from reflected sound. Can muddy frequencies or make them see louder or nonexistent if at a null.

    The quarter or half wavelength rule for a given frequency is how much you may need to move your ears from a reflecting wall to hear a noticeable difference additive or decreasing to zero.

    Optimal Gap (feet) = ¼ Wavelength = ¼ (1125 / Frequency)

    OR

    Optimal Gap (meters) = ¼ Wavelength = ¼ (343 / Frequency)

    Example 1: for a 200 Hz sound wave, the wavelength is 1125/200 = 5.6 feet. A quarter of that is 1.4 feet (0.43 meters).

    Example 2: for a 60 Hz sound wave, the wavelength is 1125/60 = 18.8 feet. A quarter of that is 4.7 feet (1.43 meters).
     
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  6. joeinid

    joeinid AK Subscriber Subscriber

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    I know, isn’t it crazy. But, we are having fun!

     
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  7. Bill Ferris

    Bill Ferris Super Member

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    Don`t want to nick pick you Velocityboat, but my 2 remaining brain cells, seem to recall, the accepted average speed of sound is 1134 ft. per second @ sea level for sound calculations, depending on measured barometric pressure, temperature and humidity if more precision is required..
    If you care to confirm, as I`m too lazy to go and grab my Gen Rad book on acoustical measurements, or Audio Cyclopedia..

    Kind regards, OKB
     
  8. Bill Ferris

    Bill Ferris Super Member

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    :crazy: :thumbsup:
     
  9. joeinid

    joeinid AK Subscriber Subscriber

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    This makes a lot of sense. Thank you for your explanation. I do agree and find some days or nights everything sounds better or worse depending on a lot of factors.

    Just swapping amps in a familiar setup, I feel I can get an overall sense what the amp is doing. I know some don’t believe that there are any differences between amps or gear in general, just overall power ratings. I just cannot subscribe to that point of view.

    These new 1.25s are definitely rocking the house. Absolutely love them.

     
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  10. jblnut

    jblnut Don't Overthink It Subscriber

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    Said the guy with the 1000 Hp Cutlass ? Lol..we're all inmates here in the house of overkill.

    jblnut
     
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  11. joeinid

    joeinid AK Subscriber Subscriber

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    Hahaha, we are all guiltily!
     
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  12. Velocityboat

    Velocityboat Super Member

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    Good point. Think of this as good enough for the slide rule crowd. I used to own one since I had a college prof whose point was to show us calculator geeks what was good enough. He also gave lessons with RCH units.
     
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  13. joeinid

    joeinid AK Subscriber Subscriber

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    Ha! RCH units. I use them all the time :)
     
  14. damacman

    damacman Blown and Injected Subscriber

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    And bridged MC2600s ... :rockon:
     
  15. jblnut

    jblnut Don't Overthink It Subscriber

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    I sold my pair of PC4002M's long ago (1400w mono 8 ohm) . Otherwise we'd have ourselves a good little bench race here :)

    jblnut
     
  16. kevzep

    kevzep Its all about the Music Subscriber

    You can't change the operating voltage on the new McIntosh products, in fact not since 2012.....they make region specific transformers now, so in order to have a 240V conversion done would involve a whole new transformer.
    Its suppose to force people like me who buy stuff from the USA, to buy from the local dealer...

    I went through this with the MEN220 and C48 I bought out of the USA, eventually I found this out I think, from the guys at AC...

    Very nice amps and those giant meters, well, to me they look just amazing!!
    Its a great time in ones journey of music and gear...I remember when I got my 452.......
     
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  17. joeinid

    joeinid AK Subscriber Subscriber

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    Now I feel like I'm in good company :beerchug:
     

     

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  18. joeinid

    joeinid AK Subscriber Subscriber

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    Thank you Kev. Even I remember when you got your 452. I remember the excitement and lived it through you.
     
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  19. kevzep

    kevzep Its all about the Music Subscriber

    This is what I believe too,of course its subjective, but the technician in me says it makes no sense for the gear to sound different as its used more, until of course you get to 30-40 years when the service life of certain components expire and/or wear out...
    What makes think this is from day to day things can sound different, I believe it is our brains at play, because music triggers pleasure centers, activates dopamine release, and such, these things can vary quite a lot depending on time of day, how you "feel" at the time, your energy levels and how fatigued and/or exhausted you are, or how energized you feel, are you sad, or angry or indifferent?....For me as an example, when I am extremely fatigued, music sounds louder and more edgy/brash than when I am fully energized.....now I know its not the system doing that....Yes humidity and temperature come into play here, but they do not have this much effect on the music especially in an enclosed space in a house for example where in my case the air is humidity controlled and filtered...
    But that's my take on it, not trying to say anyone is wrong and we are all of course entitled to believe what we want, but always good to open up the discussion with respect...
     
  20. kevzep

    kevzep Its all about the Music Subscriber

    Oh yes indeed it was very exciting times, the guilt of huge investment is something that fades quickly as the level of enjoyment it brings is something you cannot put a price on.....
    I know as I got home with the 452, it sunk in just how much money I had spent and I started feeling a bit guilty....until I fired it up....
     

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