Speaker suggestions for Adcom GFA-5500? 4 ohm or 8?

ipsullivan
ipsullivan Posts: 65
edited June 2013 in Speakers
First off, I currently have a pair of RTA 11Ts powered by an Adcom GFA-5500, and I am using a Yamaha HTR-5860 as a pre-amp.

Will I see much difference in sound quality with 4 ohm vs 8 speakers? The 11Ts are 6 ohm, does this impose any issues since the amp is only rated at 4 and 8?

The GFA5500 is rated at 350 watts into 4 ohms and 300 into 8 ohm.

I am looking for something that can utilize more of the amp's potential, also in terms of size, I would like to stick with something similar to the 11Ts.

I am also considering a dedicated pre-amp but not sure if it would be worth the money at this point. But, that is discussion for a different forum.

Any suggestions/comments would be great.

Thanks,
Ian
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Comments

  • steveinaz
    steveinaz Posts: 19,545
    edited May 2013
    The impedance rating of speakers has nothing to do with quality, it's simply a by-product of the design used. However, 4ohm speakers do need a more robust amplifier section (higher quality amp), especially if you like higher volume levels.

    When a lower impedance speaker (4ohm) is connected to an amp, it acts more like a short than a higher impedance (8ohm) speaker---therefore more current has to be availabe from the amplifier; usually higher current amps are more costly/more robust.

    Also keep in mind the speaker impedance specs are typically quoted as "nominal" (meaning: average) thru the frequency spectrum. A 4ohm nominally rated speaker may dip all the way down to 2ohms at some frequencies (typically bass freq's), and as high as 16ohms in others. Another good reason to spend the cash on a good quality amplifier.
    Source: Bluesound Node 2i - Preamp/DAC: Benchmark DAC2 DX - Amp: Parasound Halo A21 - Speakers: MartinLogan Motion 60XTi - Shop Rig: Yamaha A-S501 Integrated - Source: Rotel CD14MkII CD Player - Speakers: Elac Debut 2.0 B5.2
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  • ipsullivan
    ipsullivan Posts: 65
    edited June 2013
    ZLTFUL,

    Thanks for the advice, looks like upgrading the 11Ts would be cheaper than searching for something else.

    There is a guy locally, (Carl's Custom Loudspeakers) that does crossover upgrades. Replacing the caps and resistors he quoted me at $150, for the pair (six caps and 2 resistors). Is this reasonable? Not sure who's hardware he is using, will try to find out on Monday.

    Looking into tweeters and dynamat also.

    Thanks,
    Ian
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  • hertz9753
    hertz9753 Posts: 310
    edited June 2013
    Also check with Trey. He does great mods and is a member here. http://www.vr3mods.com/
    AVR-Onkyo TX-NR808
    Front amp-Adcom GFA 555>Polk Audio LSi9's(Vr3 Castle Mods)
    Center amp-Adcom GFA 5400>Polk Audio LSi9 bi-wired(Vr3 Castle Mod)
    Surrounds-Polk Audio F/X500's<Onkyo TX-NR808
    Sub-Velodyne SPL-1000R
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  • zane77
    zane77 Posts: 1,696
    edited June 2013
    Definately give Trey (VR3) a shout, he has a lot of experiance with doing the crossover upgades and is familiar with the speakers you have, you won't be disappointed in his work. Let him know a budget and he will figure something out for you.
    Home Theater
    Onkyo PR-SC5508 Sharp LC-70LE847U
    Emotiva XPA-5 Emotiva XPA-2 Emotiva UPA-2
    Front RTi-A9 Wide RTi-A7 Center CSi-A6 Surround FXi-A6 Rear RTi-A3 Sub 2x PSW505
    Sony BDP-S790 Dishnetwork Hopper/Joey Logitech Harmony One Apple TV
    Two Channel
    Oppo 105D BAT VK-500 w/BatPack SDA SRS 2.3 Dreadnought Squeezebox Touch Apple TV
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