Amplifier question

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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    For two professors who don't want to read the SPEC sheet, I've included the SPEC below. It's taken directly from the OP post above. It can draw 46 amps at full power. Go Figure yourself for the efficiency on this amp. In my previous post, I have also provided a link to SoundStage Review. You professors will find that it can do 750W but 1%THD which is high.

    Technical Specifications
    Appendix A -
    Technical Specifications
    Rated Power Output ............................... 500 w/ch rms @ 8ohm
    20 Hz - 40 kHz
    Frequency Response ............................... 20 Hz - 40 kHz +0 / -0.5db
    THD+N @ Rated Power Output ............. < 0.05%, 80kHz Lowpass\
    20 Hz - 40 kHz
    Signal to Noise Ratio .............................. > 88db @ 1w A-weighted
    >114db @ 500w A-weighted
    Slew Rate ................................................ > 25 V/uS
    measured @ 80 kHz
    Voltage Gain (variable) ........................... 25db - 36db
    Input Sensitivity (variable) ...................... 3.7Vrms - 1.0Vrms
    Input Impedance .................................... 47kW (Unbalanced); 100kW (Balanced)
    Output Impedance ................................. 0.005 ohm
    Damping Factor ...................................... 745 @ 50Hz / 500w / 4 ohm
    Mains Voltage ......................................... 120 VAC, 60Hz
    Mains Fuse (internal) .............................. 20 Amp
    SEVERE WARNING! Internal fuse will blow if 100% power
    5/ch is maintained for more than 15 sec. This is a safety measure to
    ensure home wiring is not damaged. Do not replace or bypass this
    fuse with higher current rating.
    Power Consumption
    - Standby .............................................. 250 mAmps
    - Idle ..................................................... 3.5 Amps
    - 50% power 5/ch ................................ 32 Amps
    - 100% power 5/ch .............................. 46 Amps
    Connector Complement ......................... 5 Each Neutrik SPEAKON output cable connectors
    Neutrik Part No. NL4FC-B
    5 Each XLR balanced input connectors
    5 Each RCA unbalanced input connectors
    1 Each RS232 network control connector
    Unit Weight ............................................ 89 lbs/40kg
    Shipping Weight ..................................... 109 lbs/49kg
    Overall Dimensions ................................ 11”(H) x 17”(W) x 27“(D) (43 x 28 x 68.5 cm) including
    SPEAKON cable connectors.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    nguyendot wrote: »
    I don't have to assume what the efficiency is, the fact is no amp is 100% efficient. You don't have to assume that, it's a given.

    Either way, go get the amp benched. Until you do, you can't come in saying it puts out X watts because you honestly don't know, do you?

    I say Ignorance is a Bliss. A SPEC sheet is just one blink away but you didn't read. You don't happen to be Psychic, are you? Oh wait, Psychic don't say craps like that without reading or listening first.

    You live in your own world of assumption (assume - which reads ****-U-AND-ME to Engineers)!

    Do you think I am an EE without any test equipment at home? I'll tell you what, I have all the tools I need to test, design and build a Power Amplifier if I need to. Is that good enough for you?

    I also don't have this amp to bench test. But you (and your buddy ViperZ) are crapping in a thread with basic truth about efficiency but once again, fail to read the SPEC sheet and understand what it said.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • nguyendot
    nguyendot Posts: 3,594
    edited September 2009
    megasat16 wrote: »
    I say Ignorance is a Bliss. A SPEC sheet is just one blink away but you didn't read. What kind of intelligence do you possess? You don't happen to be Psychic, are you? Oh wait, Psychic don't say craps like that without reading or listening first.

    You live in your own world of assumption (assume - which reads ****-U-AND-ME to Engineers)!

    Do you think I am an EE without any test equipment at home? I'll tell you what, I have all the tools I need to test, design and build a Power Amplifier if I need to. Is that good enough for you?

    I never stated it was 100% efficient, nor 80%, I just said take for example if it was. You read wrong. I even stated it's not close to 80%, which with 46amps of draw at full burn - is less than 50%.

    This thing will never pull 500w continuous all channels. If it can't do it for longer the 15s, it's not continuous is it? It's for 15s.
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    nguyendot wrote: »
    I was just too lazy to READ THE SPEC :)

    There you go, Fixed for you! Huh? ;)
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    nguyendot wrote: »
    I never stated it was 100% efficient, nor 80%, I just said take for example if it was. You read wrong. I even stated it's not close to 80%, which with 46amps of draw at full burn - is less than 50%.

    This thing will never pull 500w continuous all channels. If it can't do it for longer the 15s, it's not continuous is it? It's for 15s.

    You don't even know why it has a internal fuse! Read again, it's to protect your home wiring! What a load of crap!
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • nguyendot
    nguyendot Posts: 3,594
    edited September 2009
    megasat16 wrote: »
    You don't even know why it has a internal fuse! Read again, it's to protect your home wiring! What a load of crap!

    I did read that, I never said that wasn't the point of the fuse. But the fuse restricts the amount of possible current draw. 20A fuse? Even at 50% output it pulls over 30 amps... which would blow the fuse over any more than continuous usage.

    Either way, if the fuse is going to blow, regardless of it's purpose, this unit can't put out it's rated output continuously, since obviously it will shut down.
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    Ok, Prof. You amazes me! What it can do and why it shouldn't do is two very different things.

    The fuse is slow blow type (time delayed fuse) which will not blow right away even if it passes the 20A rating. It can withstand 46 amps for 15s before it blew.

    The reasons 20A fuse was put in there could be many.

    1. The small Size Heatsinks are not adequate enough to dissipate 500W continuous power for a prolong period of time. The thermal protection will kick in or thermal runaway will occur for the output devices (or anything really).

    2. You won't be in anywhere near it when it's doing 2500W full output. It's deafening and very dangerous for the listener at this kind of SPL.

    3. Most speakers will just give up at 500W full power so it's a way to protect speakers.

    4. God knows what else they were thinking. I have no idea. I did not design, build or own or test this amplifier. But I'll remind you once again, you and ViperZ are crapping in the thread with very basic knowledge and providing wrong information which is confusing to the readers.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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  • kn505
    kn505 Posts: 380
    edited September 2009
    megasat16,

    The specs has the Output Impedance = 0.005 ohm. Does this mean that the amp can go below 8 ohms to maybe 0.005 ohm?

    Thanks.
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  • megasat16
    megasat16 Posts: 3,521
    edited September 2009
    :eek: The short, simple and sweet answer is NO! :D

    You are confusing the amplifier output impedance with the amplifier ability to drive low load impedance.

    The output impedance of an amplifier should be zero (so all power from amplifier can be transferred to the speakers without any power loss) but it never really happens in real life. It's complicated to explain the output impedance in simple English. But it's important for the Speaker Manufacturer for calculating efficiency of the speakers.

    You should not use this amp with less than 4 ohms speakers (load) just like Ken said.
    Trying out Different Audio Cables is a Religious Affair. You don't discuss it with anyone. :redface::biggrin:
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