Pro amps for hi-fi

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Mon Dec 21, 2015 3:17 am

  • Hello, I 'm a newbie from Rome, Italy. I bought a QSC ISA 280 power amp to drive my old Acoustic Research AR 3 hi-fi loudspeakers because it would be a very stable amp on low impedance loads: AR 3 are nominally 4 ohm, but they reaches 2,7 ohm in mid-low region , and they are very low efficiency speakers. The amp arrived today, and I bought it from ISA Series because it's very similar to an hi-fi amp, class AB output, and it's for installed audio systems, but my question is, there are some better sounding amps in QSC series? Thank you, best regards, Adriano Galvani
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Mon Dec 21, 2015 11:52 am

  • The PLX series amps are measurably better than the ISA (lower noise and distortion, for example), but the difference is very small and probably inaudible except perhaps in a very controlled listening environment.

    Good amps don't have a "sound." They accurately reproduce the signal put into them, so the true way to make an amp sound good is to put a good sounding signal into it, and use an accurate, high-performing loudspeaker.
    Bob Lee
    Technical Communications Developer
    QSC, LLC
    Fellow, Audio Engineering Society
    "If it sounds good, it is good." —Duke Ellington
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    Bob Lee
    QSC Audio Products
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Mon Dec 21, 2015 12:49 pm

  • Thank You, I'm listening to the ISA 280 and I have to say that it's one of the best performing amps I 've ever heard , clean , transparent , dynamic and powerful . I 've had Crown PSA-2 , an excellent amp , but this ISA 280 has incredible bass , full , rich and fast . And it' smooth as a very hi-fi amplifier. And precise, precise, precise ! Best regards, Adriano Galvani
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Mon Jan 23, 2017 2:52 pm

  • Hello to everyone from Montréal QC :wink:

    English is not my first language, i will try to do my best to write without too much mistake...

    Same as Sonnar, i will like to use QSC amplifier in a home hi-fi sound system. But i want a sound system that, when i listen a dvd of a rock show, it's like i'm there live in the middle of the people...

    My loudspeaker are BostonAcoustics T1030, they can handle 15 to 150 watts, 200 watts peak.
    I will try to find a second pair of T1030 and adding two subwoofer in the system.
    The pre-amplifier will be a C500 from Cambridge Audio.
    DVD/CD player are Denon, i will maybe upgrade for someting better in the future, and possibly a computer and a DAC

    I know the QSC 1200 Series One,100 Watts Channel, one of my friends have one, and i try it on my Boston and it's sound really great compared than my Denon Receiver, more dynamic, more bass, more feeling...

    Other than the 1200, wich other QSC amplifier around 100 to 150 Watts, no cooling fan, convection cooling only, has been produced in the past, and/or presently, witch one is better than a other one and why?

    The plan is to connect 4 T1030 on 2 Amplifier, and having 2 amplifier in bridge mode for the subwoofer, possibly DIY enclosure for the sub, and did QSC have electronic 2 way cross-over to separate the signal for sub and the rest of the system


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Fri Jan 27, 2017 9:03 am

  • You might be able to find an old USA-series amplifier. They're quite old and fairly cheap.
    They have fans, but its a very big fan so it runs very quietly unless you use a lot of power.
    They're class AB (some of them class H), big transformer and lots of capacitors. Ideal HiFi amp.

    I have a USA-850, it ran my HiFi for years until I got some active monitors. 220w/ch into 8ohm, 425w/ch into 4ohm, 550w/ch into 2ohm. Bridged would be 850w into 8ohm, 1100w into 4ohm. Running at 2ohm or 4ohm bridged will make it get very hot if you turn it up.

    The high rail
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    Location: Sheffield, UK

Fri Jan 27, 2017 10:22 pm

  • Hello

    Thank you chriss661 for your reply

    During the last days, i just find a pair of USA400 on kijiji ad's, 320$ canadian for them after discussion with the seller who is asking 400$ at the beginning for them on his ad's, both are built on 1996, fanless amplifier, 110-125 Watt channel / 8 Ohms, perfect for me with my home BostonAcoustics loudspeakers, and, if i need more power for more powerfull speaker, bridged mode give 400 watts / 8 Ohms, with 2 amplifier, 800 Watts stéréo, enough power for a basement party...

    It's a good beginning for my home sound system project :D

    I am still interested to know all the model of QSC fanless amplifier, wich one will be the best, a kind of palmares of fanless amplifier, if someone at QSC can foward the information, i will really appreciate.

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