OMG!!! New MC1.25KW !!!

Discussion in 'McIntosh Audio' started by joeinid, Sep 29, 2017.

  1. kevzep

    kevzep Its all about the Music Subscriber

    It wasn't a bad review at all, and you'd have to wonder with it shutting down at less than 10% of its rated continuous power output about a fault, and I certainly wouldn't blame anyone for not wanting to heave another one of those amps into position for another go.

    There may have also been something going on behind the scenes nobody will ever know about too.

    Agreed, and I think we can safely put this one to bed.
     
  2. C6Bill

    C6Bill AK Subscriber Subscriber

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    And here I was thinking this would be a thread about the new MC1.25KW. If anyone has more information on that I'd love to hear it.
     
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  3. E-Stat

    E-Stat Super Member

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    As previously stated, Mr. Atkinson merely quoted from the manual.
     
  4. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    MC501 owners manual
    http://www.berners.ch/McIntosh/Downloads/MC501_own.pdf
    Page 2
    IMPORTANT SAFETY INSTRUCTIONS! PLEASE READ THEM BEFORE OPERATING THIS EQUIPMENT.

    1. Read these instructions.
    2. Keep these instructions.
    3. Heed all warnings.
    4. Follow all instructions.
    5. Do not use this apparatus near water.
    6. Clean only with a dry cloth.
    7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
    8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.


    Page 3
    5. In the event the MC501 over heats, due to improper ventilation and/or high ambient temperature, the protection circuits will activate.
    The Power Guard LED will stay ON and the audio will be muted. When the MC501 has returned to a safe operating temperature, normal operation will resume.

    Page 6

    Always provide adequate ventilation for your MC501. Cool operation ensures the longest possible operating life for any electronic instrument. Do not install the MC501 directly above a heat generating component such as a high powered amplifier. If all the components are installed in a single cabinet, a quiet running ventilation fan can be a definite asset in maintaining all the system components at the coolest possible operating temperature.

    A custom cabinet installation should provide the following minimum spacing dimensions for cool operation. Allow at least 6 inches (15.24 cm) above the top, 2 inches (3.81cm) below the bottom and 1 inch (2.54 cm) on each side of the amplifier, so that airflow is not obstructed. Allow 16 inches (40.64 cm) depth behind the front panel. Allow 1-3/16 inches (3.02 cm) in front of the mounting panel for knob clearance. Be sure to cut out a ventilation hole in the mounting shelf according to the dimensions in the drawing.

    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
    Ok now the mc 501 thermal shutdown has been well documented over the years and the hands on use of this amp has found...

    One needs to follow the instructions!!

    99% of the thermal shutdown owners have experienced, have been because of not following the instructions.

    If you can't follow the instructions and limited space you can opt to add fans to your system. McIntosh chose not to add fans in this amp because they where not needed if you follow the parameters they specifically outlined.

    This topic is so old it's irrelevant and to use the argument that a test result when the amp was new and a tested quickly for an article. The fact is in the hands of owners that read instructions they don't have issues with this amp.

    You can google for plenty on it

    mcintosh mc 501 thermal shutdown
    https://www.google.com/search?rlz=1...i13k1j0i7i30k1j0i13i30k1j0i30k1.0.IEeNskT1YYI
     
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  5. 62caddy

    62caddy Trust but verify Subscriber

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    If you owned an McIntosh PG amplifier, you would understand better how it operates. The event as told by JA does not fit the description of a PG event. It is apparent that when the amplifier is in thermal protection mode PG lamps serve to alert of this condition.

    Further worth noting is McIntosh amplifiers have something like 4 or 5 separate protection circuits: Power Guard, Sentry Monitor, thermal guard, shunting of output if DC appears at the outputs and one other(?) I believe.

    Back in the early '80s, Julian Hirsch tested an MC2255, he stated the amplifier "literally defied our attempts to blow it up" by shorting the outputs and then applying full power tone bursts! Few amplifiers would tolerate that type of abuse without considerable damage. It goes to show the level of care that goes into the design of McIntosh products.

    To criticize the product on such a arbitrary criteria (nearly impossible to be encountered under normal use) at the outright dismissal of the amplifier's many other fine attributes seems a bit disingenuous. In the final analysis, McIntosh has among the highest resale value in the hi fi industry. This alone speaks volumes about the quality, longevity and engineering integrity of Mc products, your protestations notwithstanding.

    @kevzep - thanks for clarifying the distinction between Sentry Monitor and thermal protection which JA appears to have used interchangeably.
     
    Last edited: Oct 11, 2017
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  6. 62caddy

    62caddy Trust but verify Subscriber

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    We have a winner! :thumbsup:
     
  7. E-Stat

    E-Stat Super Member

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    There's the simple answer. Thanks!
     
  8. Velocityboat

    Velocityboat Well-Known Member

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    Concur. My MC1000 lit a PG lamp for a capacitor failure in a powersupply circuit not directly related to PG operation. Amp would drive a signal on meter no PG light but with speaker load connected a PG light and no signal out.
     
    Last edited: Oct 11, 2017
  9. Chubba

    Chubba Active Member

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    So back to the new Mc1.25KW.I installed four fans inside the chassis of my MC-252 (I followed the instructions for ventilation) forcing air to flow up threw the heat sinks and have never had a shut down since.The 252 is the same chassis as the 501 but 250 w x two.Ron C I believe said due safety laws they had to lower the shutdown level for the 252,501.I think the heat sinks should have been larger or better yet built in fans since the cut outs for air flow were there.
     
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  10. restorer-john

    restorer-john Super Member

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    This is a follow up manufacturers comment to another Mc review.

    https://www.stereophile.com/content/mcintosh-mc1201-monoblock-power-amplifier-manufacturers-comment

    Charlie Randall (McIntosh Laboratory)
    "A comment about the 40-minute operation at 1/3 power: This is done to keep the top cover of the amplifier from exceeding 65 degrees C, which is a requirement for CE certification. The unit is designed using parts that are safely operated at 80 degrees C and higher. Allowing the unit to shut down at 65 degrees C is extending the life of the product. The only music material that is really available today that is compressed enough to represent 1/3 power would perhaps be an FM radio station (if you could imagine listening to 400W continuous). It is reported that the amplifier needed to be reset when this occurred—the reset is automatic. Once the amplifier overheats, it mutes the input; after it cools down, it then unmutes automatically. There is no reset required by the user"
     
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  11. Velocityboat

    Velocityboat Well-Known Member

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    Thus the emergence of thermal track soon after. Engineering progression to meet legislative restrictions. Like smog controls in 1974 forcing fuel injection and computer control advances in automobiles to get power and performance back without compromises.
     
  12. exhippy

    exhippy I use to have long hair. Now I'm lucky to have any Subscriber

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    Damn! ...and I was going to buy these new amps and hook-up old cheap speakers just to blow them up.
    I guess power guard won't let me...:D


    smoking_voice_coil.850x0.jpg

    Programming.jpg

    .
     
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  13. Chubba

    Chubba Active Member

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    Thanks for not shutting this thread down.I finally think this thing looks cool.But who am I ? Just a lowly MC-252 owner in search of a winning lottery ticket.Strange things happen in life.New amps/run over by a bus, Cheers!
     
  14. kevzep

    kevzep Its all about the Music Subscriber

    Not quite, powerguard will let you, just wont let you do it with distortion....:yikes:
     
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  15. joeinid

    joeinid Well-Known Member

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    These MC1.25KW amps are definitely on my radar. If they are in fact, half size single chassis MC2KW-like amps as I suspect, I will officially go nuts.

    Thank you McIntosh for making us crazy. :)
     
    Last edited: Oct 12, 2017
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  16. exhippy

    exhippy I use to have long hair. Now I'm lucky to have any Subscriber

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    That's good to know. I like to hear my old speakers screaming for their life without distortion...:rflmao:

    young_frankenstein.jpg
     
    Last edited: Oct 13, 2017 at 12:12 AM
  17. twiiii

    twiiii Super Member

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    If anyone would read Crowns and QSC latest owners manuals they have found and confirmed even under the most demanding live concert requirements the average duty cycle for an amp is about 1/8 of its continuous just before clipping rating. Thats far below the 1/3 power test of the FTC requirements. So for music unless your driving the amps into compression by activating the PG function you will never see the 1/3 continuous power condition. Older Mac amps like the 2255 were designed to run all day at any level with out an over heating issue with adequate ventilation, but they didn't have the current reserve or the dynamic capabilities of the latest amplifiers including the MC501. Todays amps are designed to handle signals with a much higher crest factor driving more adverse loads than amplifiers of the distant past. Which would you rather have a 2600 with its noisy fans, or a 1.2 K amp to drive a pair of 1k speaker or a S7 from Magico. I'd take the 1.2k myself. Neither a MC2255 or a 7300 will drive a 4 ohm load from its 8 ohm tap at a higher than rated power level and exceed specs like a MC 501.
     
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  18. Velocityboat

    Velocityboat Well-Known Member

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    Having driven 1200 watt per channel speakers 8 ohm and 4 ohm speakers that suck up 1000 WPC ohm with MC2500s bridged. I can attest the fans can be heard when passages go quiet. The fanless quad balanced MC1000 does same loads without the fan, and is quieter in upper registers during peaks. If I could run MC2500 out of listening area difference maybe less. I am not convinced light fog in highs was not fans. Thing is extended 300 to 400 WPC peaks will cause fans to run intermittently and lessen experience. So yes MC1.2KW would be my next choice.

    Not having experienced MC2600, which has more current capability closer to MC1.2KW, I suspect bridged difference would be closer to a fan-less big Mc quad balanced amp than MC2500. I am relying on @damacman to school me in bridged MC2600 in AZ next week.
     
    Last edited: Oct 13, 2017 at 2:16 PM
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  19. kevzep

    kevzep Its all about the Music Subscriber

    Put it this way, the Crown Macro-Tech 5002VZ when using a nasty Arbitrary wave file, which is a pulse, 50hz and 1khz component, will at 30% continuous power into 2Ω go into current limit after 7mins, this happens as the heatsink temp reaches 100˚C (212˚F). I have tested this over and over as we replace the entire output sections in these amps with an upgrade, pretty much have to factory test them.
    But the same test at 4Ω, at 30% continuous power, they hold steady.
    Same test at 8Ω is pointless as they can run at full power indefinitely.

    So its when you introduce a serious current situation this is when things get hot.

    I am however when I put the next one together, going to just use a 1khz tone and see what happens then, I suspect they will exceed the 30mins test easily. We use this particular odd file because we actually want to test the amplifiers protection.

    So, in summary, any amplifier which is convection cooled as the 501 is, which is capable of such power and current is actually a miracle!!

    Oh what I forgot to say also, was in all the 15 years we have been using these Crowns in our large format concert system with all manner of bands, I have NEVER once EVER seen on shut down because it cannot manage the thermal management requirements....
     
    Last edited: Oct 13, 2017 at 3:02 PM
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  20. kevzep

    kevzep Its all about the Music Subscriber

    Sorry,. we keep derailing this thread, but there is a good discussion going on here....

    I think what McIntosh does is underrates their amplifiers, the MC452 is a monster, they say its 450watts per channel, but really it can easily do 900 watts per channel for short periods.....other manufacturers might say it was a 900watt amp? Who knows...

    In fact, you know what, I am going pull my 452 out of its hole here and run some tests on it to see what it can actually do!!
     
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