Amp for LSI15's

tcrossma
tcrossma Posts: 1,301
edited July 2007 in Electronics
In preparing to make my move to upgrading to the LSI15's i'm researching amps. I've already had some great advice given on this forum, and I know there's a lot of good amps out there by Adcom, Rotel, Outlaw, etc.

I also know the LSI15's want power. My question is, since the LSI15's are 4ohm speakers, is the amp wattage @ 4ohm the important number to look at? If I see a "125 watts @ 8ohms, 200 watts @ 4 ohms", is that sufficient, or do I want to be looking at the wattage at 8ohms when making my decision?

This is probably a dumb question, but there's a huge difference in price between "200watt @ 8ohms" and "200 watt @ 4 ohms" amps.

Thanks for any tips.

tim
Speakers: Polk LSi15
Pre: Adcom GFP-750 with HT Bypass
Amp: Pass Labs X-150
CD/DVD Player: Classe CDP-10
Interconnects: MIT Shortgun S3 Pro XLR
Speaker cables: MIT MH-750 bi-wire
TT:Micro Seiki DD-35
Cartridge:Denon DL-160
Phono Pre:PS Audio GCPH
Post edited by tcrossma on
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    Tim you first need to tell us what yor budget is. Then we can recomed the best amps in that price range. :)

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • tcrossma
    tcrossma Posts: 1,301
    edited July 2007
    Shannon W. wrote: »
    Tim you first need to tell us what yor budget is. Then we can recomed the best amps in that price range. :)

    Shannon

    I'm hoping to spend in the $800 range on the amp. Also, since this is a combination HT/Music setup, i'm hoping to get 3 channels on the new amp to power the LSi15's and an LSiC. The rears i'll probably let my Yamaha RX-V2500 power.

    thanks,

    tim
    Speakers: Polk LSi15
    Pre: Adcom GFP-750 with HT Bypass
    Amp: Pass Labs X-150
    CD/DVD Player: Classe CDP-10
    Interconnects: MIT Shortgun S3 Pro XLR
    Speaker cables: MIT MH-750 bi-wire
    TT:Micro Seiki DD-35
    Cartridge:Denon DL-160
    Phono Pre:PS Audio GCPH
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    Check eBay for a rotel 1080, Sunfire CINEMA GRAND 2ch, Carver TFM-55x. Those would be my first choices for that budget. My second choice would be some outlaw mono blocks.

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • tcrossma
    tcrossma Posts: 1,301
    edited July 2007
    I'm not adverse to going used either. What does anyone think of the Adcom 5503?

    tim
    Speakers: Polk LSi15
    Pre: Adcom GFP-750 with HT Bypass
    Amp: Pass Labs X-150
    CD/DVD Player: Classe CDP-10
    Interconnects: MIT Shortgun S3 Pro XLR
    Speaker cables: MIT MH-750 bi-wire
    TT:Micro Seiki DD-35
    Cartridge:Denon DL-160
    Phono Pre:PS Audio GCPH
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  • cfrizz
    cfrizz Posts: 13,415
    edited July 2007
    The more watts you have in the 8ohm catagory, the more you will have when it has to push 4ohms! Speakers get damaged from getting too little power not too much power. So the more you can get the better off you will be.
    Marantz AV-7705 PrePro, Classé 5 channel 200wpc Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony XBR-49X800E TV, Polk S60 Main Speakers, Polk ES30 Center Channel, Polk S15 Surround Speakers SVS SB12-NSD x2
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    x2

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • Bill Ayotte
    Bill Ayotte Posts: 1,860
    edited July 2007
    tcrossma wrote: »
    I'm hoping to spend in the $800 range on the amp. Also, since this is a combination HT/Music setup, i'm hoping to get 3 channels on the new amp to power the LSi15's and an LSiC. The rears i'll probably let my Yamaha RX-V2500 power.

    thanks,

    tim

    I would scrap up about $200-250 more and get a 5 channel Sunfire....That way, when you upgrade the rears, you already have the power in place...You can find a used Sunfire 200/5 for around $1000.....Totally worth the extra $200 IMO....
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  • Sami
    Sami Posts: 4,634
    edited July 2007
    Aragon 2004 for the mains and 3ch Acurus for the rest, that's what I would recommend and fits right in the budget. As for your question about watts, it's impossible to say because not all watts are created equal. It's safe to say though that any quality amp at 125w@8/200w@4 is enough for the 15's. I'm running my LSi's (15's as mains) with 5ch 125w@8 B&K and power isn't an issue.
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  • tcrossma
    tcrossma Posts: 1,301
    edited July 2007
    Thanks everyone, very good info.

    tim
    Speakers: Polk LSi15
    Pre: Adcom GFP-750 with HT Bypass
    Amp: Pass Labs X-150
    CD/DVD Player: Classe CDP-10
    Interconnects: MIT Shortgun S3 Pro XLR
    Speaker cables: MIT MH-750 bi-wire
    TT:Micro Seiki DD-35
    Cartridge:Denon DL-160
    Phono Pre:PS Audio GCPH
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  • george daniel
    george daniel Posts: 12,096
    edited July 2007
    If you want those 15's to really sing ,get a high current/power,, big A$$ sand amp :)
    JC approves....he told me so. (F-1 nut)
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  • jamiestarr1966
    jamiestarr1966 Posts: 8
    edited July 2007
    I have a similiar situation... My setup is:

    Denon 3805
    LSi15
    LSic
    Fxi5 Surrounds
    SVS PB12-ISD Sub-woofer
    Denon DVD-900

    I am also looking for a amplifier in the $800-1000.00 range. I was considering the Outlaw 7201 at 125 watts but I would really like an amp that produces 200 watts. I saw a used Sunfire on Ebay but I am nervous about buying used equipment. If you purchase a used amp and it fails then you are just screwed right?
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    Whats nice about Sunfire is that no matter whats wrong with it they say its a flat $250 to fix. But then again THEY SAY... LoL

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • wingnut4772
    wingnut4772 Posts: 7,519
    edited July 2007
    Earthquake Cinenova + LSI15 = Happy Happy.
    Sharp Elite 70
    Anthem D2V 3D
    Parasound 5250
    Parasound HCA 1000 A
    Parasound HCA 1000
    Oppo BDP 95
    Von Schweikert VR4 Jr R/L Fronts
    Von Schweikert LCR 4 Center
    Totem Mask Surrounds X4
    Hsu ULS-15 Quad Drive Subwoofers
    Sony PS3
    Squeezebox Touch

    Polk Atrium 7s on the patio just to keep my foot in the door.
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  • jamiestarr1966
    jamiestarr1966 Posts: 8
    edited July 2007
    Shannon W. wrote: »
    Whats nice about Sunfire is that no matter whats wrong with it they say its a flat $250 to fix. But then again THEY SAY... LoL

    Shannon


    OK...lol

    So if I made a decision to purchase this unit...I could ship it back to the manufacturer if by chance the unit is defective?
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  • jamiestarr1966
    jamiestarr1966 Posts: 8
    edited July 2007
    wingnut4772 wrote: »
    Earthquake Cinenova + LSI15 = Happy Happy.

    Just look up the cost for that amp...Based on all the responses it appears I will have to wait, be patient and save more money to get the right amp!!:(
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  • wingnut4772
    wingnut4772 Posts: 7,519
    edited July 2007
    jamiestarr1966 wrote: »
    Just look up the cost for that amp...Based on all the responses it appears I will have to wait, be patient and save more money to get the right amp!!:(

    Look for a used one.
    Sharp Elite 70
    Anthem D2V 3D
    Parasound 5250
    Parasound HCA 1000 A
    Parasound HCA 1000
    Oppo BDP 95
    Von Schweikert VR4 Jr R/L Fronts
    Von Schweikert LCR 4 Center
    Totem Mask Surrounds X4
    Hsu ULS-15 Quad Drive Subwoofers
    Sony PS3
    Squeezebox Touch

    Polk Atrium 7s on the patio just to keep my foot in the door.
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  • jamiestarr1966
    jamiestarr1966 Posts: 8
    edited July 2007
    wingnut4772 wrote: »
    Look for a used one.

    Based on those prices I have no choice but to buy a used one. Never bought used equimpent online. How do you protect yourself to ensure that you are buying a good unit? Sorry if I sound paranoid...lol
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  • wingnut4772
    wingnut4772 Posts: 7,519
    edited July 2007
    Look for feedback and I only pay with Paypal so at least I can file a claim if worse comes to worst.
    Sharp Elite 70
    Anthem D2V 3D
    Parasound 5250
    Parasound HCA 1000 A
    Parasound HCA 1000
    Oppo BDP 95
    Von Schweikert VR4 Jr R/L Fronts
    Von Schweikert LCR 4 Center
    Totem Mask Surrounds X4
    Hsu ULS-15 Quad Drive Subwoofers
    Sony PS3
    Squeezebox Touch

    Polk Atrium 7s on the patio just to keep my foot in the door.
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  • jamiestarr1966
    jamiestarr1966 Posts: 8
    edited July 2007
    wingnut4772 wrote: »
    Look for feedback and I only pay with Paypal so at least I can file a claim if worse comes to worst.


    Will definitely do that. Thanks for the advice...
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    jamiestarr1966 wrote: »
    OK...lol

    So if I made a decision to purchase this unit...I could ship it back to the manufacturer if by chance the unit is defective?

    From what I have been told. YES. ;)

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • Sami
    Sami Posts: 4,634
    edited July 2007
    jamiestarr1966 wrote: »
    Just look up the cost for that amp...Based on all the responses it appears I will have to wait, be patient and save more money to get the right amp!!:(

    Some e-bay auctions below, no affil.

    A little out of your price range but seems to be very highly regarded amp:

    http://cgi.ebay.com/MONSTER-CABLE-MPA5150-FIVE-CHANNEL-POWER-AMP_W0QQitemZ260137068484QQihZ016QQcategoryZ14973QQrdZ1QQcmdZViewItem

    This would make the 15's sing very happy, just add a mono-block for the centre or 3ch amp:

    http://cgi.ebay.com/Aragon-4004-Dual-Mono-Power-Amplifier_W0QQitemZ290134970282QQihZ019QQcategoryZ67786QQrdZ1QQcmdZViewItem

    5ch amp that would power the 15's w/o a problem and sound very good doing it, plus it doesn't cost you much (I have the same amp powering my LSi's):

    http://cgi.ebay.com/B-K-B-K-Components-LTD-AV5000-Power-Amplifier-700W_W0QQitemZ110144960555QQihZ001QQcategoryZ14973QQrdZ1QQcmdZViewItem

    I have no experience with this one but if it doesn't go much higher would probably work at least for the centre/surrounds:

    http://cgi.ebay.com/B-K-Sonata-Series-Video-Series-5-Channel-Amplifier_W0QQitemZ160133156144QQihZ006QQcategoryZ23787QQrdZ1QQcmdZViewItem
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    I know there are allot of people that bash Monster products, but I have heard nothing but good things about their Amp. So that might be an option also.

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • Gaara
    Gaara Posts: 2,415
    edited July 2007
    Tim,

    A 4ohm load draws more current then a 8ohm load. That being said a 200wpc into 8 ohm amp will give you more then 200wpc into 4 ohms. That is why they cost more since you are comparing apples and oranges comparing a 200wpc into 8ohm and 200wpc in 4 ohm amps.

    That being said if I were looking into a high current amp one way to tell how much power you will really get is how well it does with a 4 ohm load or lower. A perfect amp that was 200wpc into 8 ohms would double to 400wpc into 4 ohms since it is half the resistance.

    Think of it like a hose and water pressure, if you have tons of water pressure and you double the size of the hose you get double the water. If you had less pressure then doubling the size of the house wouldn't give you double the water.

    For example the Cinenova is a power house, 300wpc 8 ohms and it doubles to 600wpc int 4 ohms. Sunfire is even more impressive 225wpc at 8ohms, 450wpc at 4ohms, and 900wpc at 2ohms.

    As for specific recomendations, I have had good luck with the LSi series with Earthquake, ATI, Sunfire, and Parasound amps.
    The Basement HT
    PC Rig
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  • cfrizz
    cfrizz Posts: 13,415
    edited July 2007
    Welcome Jamie! Don't forget about Audiogon.com. Right now they have a lot of Sunfire amps for sale.
    Marantz AV-7705 PrePro, Classé 5 channel 200wpc Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony XBR-49X800E TV, Polk S60 Main Speakers, Polk ES30 Center Channel, Polk S15 Surround Speakers SVS SB12-NSD x2
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  • Sami
    Sami Posts: 4,634
    edited July 2007
    If you do a search, there are a few amps for sale in CP that would serve you well.

    I guess I could link them here as well:
    http://www.polkaudio.com/forums/showthread.php?t=54880
    http://www.polkaudio.com/forums/showthread.php?t=54704

    I'd get that Rotel ASAP if I was you.
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    Sami,

    You beat me to the link on the Rotel! That would be and Awsum amp to run those 15 and at that price you better jump on that FAST! Then you could Bi-amp them and still have one channel left for what ever you would want.

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • cfrizz
    cfrizz Posts: 13,415
    edited July 2007
    One of you in here looking for an amp should jump on this!

    http://www.polkaudio.com/forums/showthread.php?t=54864
    Marantz AV-7705 PrePro, Classé 5 channel 200wpc Amp, Oppo 103 BluRay, Rotel RCD-1072 CDP, Sony XBR-49X800E TV, Polk S60 Main Speakers, Polk ES30 Center Channel, Polk S15 Surround Speakers SVS SB12-NSD x2
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  • engtaz
    engtaz Posts: 7,664
    edited July 2007
    +1 cfrizz

    I just wish I could swing it.
    engtaz

    I love how music can brighten up a bad day.
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  • Shannon W.
    Shannon W. Posts: 568
    edited July 2007
    Man there are Two good deals for this guy. He must be living right... It took me forever for my amp deal to fall in my lap and he get two a few days apart!


    Scotty? I need more power for my LSi15's!

    Damn it Capitan! I'm giving you all the power we've got Sunfire and Rotel and I can't give you any more!

    Shannon
    50" Samsung Plasma
    Sony STR-DA4ES "use as Pre/amp"
    Pioneer Elite DV-45A DVD Player
    DLO HomeDock Deluxe iPod docking station
    Directv HR20 Sat. Receiver in black
    Sunfire Cinema Grand 7 Signature Amp
    Monster Cable AVS2000
    Monster Cable HTPS 5100 MKII
    Polk LSi 9's Front R/L
    Polk LSiC Center
    Polk LSiFX R/L Surround
    Polk LSi 7's Rear R/L
    SVS PB12-Plus/2
    Velodyne SMS-1
    Sony PS3
    Click Here To View my Rig
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  • tcrossma
    tcrossma Posts: 1,301
    edited July 2007
    That Sunfire sure does look good. A bit higher than I was thinking of spending initially, but it's probably the long term solution I really want.

    I might not be ready for a couple week to part with that much money, but when it's time I do think i'm going to look for a Sunfire Cinema Grand.

    tim
    Speakers: Polk LSi15
    Pre: Adcom GFP-750 with HT Bypass
    Amp: Pass Labs X-150
    CD/DVD Player: Classe CDP-10
    Interconnects: MIT Shortgun S3 Pro XLR
    Speaker cables: MIT MH-750 bi-wire
    TT:Micro Seiki DD-35
    Cartridge:Denon DL-160
    Phono Pre:PS Audio GCPH
    · Share on FacebookShare on Twitter