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Frank840
Frank840 Posts: 262
edited May 2008 in Electronics
I was wondering if someone could lead me to a website or explain to me Ohms 8,4,2 on amps how does it convert stuff like that.

Say I have a Amp that puts out 100 wpc at 8 ohms and i have speakers like the LSi 9's which are run at 4ohms, Does the amp change it self is they settings i just dont understand. Thanks Frank
- This your Bush?
Pioneer Elite Sc-25
Polk Lsic,15's,9's, PSW1000
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  • ben62670
    ben62670 Posts: 15,969
    edited May 2008
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    Hey Frank. Ohms is resistance so if there is less resistance more currant can flow through(watts). The limiting factor is the power supply in the amp. This is where most receivers fall short. If there isn't enough supply the output suffers, and distortion/clipping will result. Also many amps with an inadequate amount of output transistors end up running hot, and going into thermal overload, and shut down, or worse blow out. No settings actually change, but some receivers have a setting that can be changed that limit currant to protect the output devices. I hope this helps.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • ViperZ
    ViperZ Posts: 2,046
    edited May 2008
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    Some receivers/amps were made to drive 8-Ohm (and higher) speakers. You have a good chance of not just running your receiver hot with 4-Ohm speakers, but blowing the output stage, because it can't handle the current.

    I am pretty sure that if you want to use your Pioneer receiver with 4-Ohm speakers, that's a bad idea. You'll need a 4-Ohm capable amp or receiver.

    Your receiver has pre-outs, so all you need is a good 2-channel amp to drive 4-Ohm LSi9 speakers.

    Reference to Pioneer receiver info:
    http://www.pioneer.co.uk/uk/products/archive/VSX-D812-K/index.html


    Please note, some receivers are called 'high current' receivers (like Harman Kardon) - those are usually able to drive 4-Ohm speakers.
    Panasonic PT-AE4000U projector for movies
    Carada 106" Precision Series (Classic Cinema White)
    Denon AVR-X3600H pre/pro
    Outlaw 770 7-channel amplifier
    B&W CDM1-SE fronts
    B&W CDM-CNT center
    B&W CDM1 rears on MoPADs
    JBL SP8CII in-ceiling height speakers
    Samsung DTB-H260F OTA HDTV tuner
    DUAL NHT SubTwo subwoofers
    Oppo BDP-93 Blu-Ray player
    Belkin PF60 Power Center
    Harmony 1100 RF remote with RF extender
    Sony XBR-X950G 55" 4K HDR Smart TV + PS3 in the living room
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  • Frank840
    Frank840 Posts: 262
    edited May 2008
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    how do you all feel about this amp. i figure i could buy it and fix it. it says "High Current" but 100wpc at 8ohms that is why i get confused.

    http://cgi.ebay.com/ADCOM-GFA-545-II-HIGH-CURRENT-POWER-AMPLIFIER-2-CHANNEL_W0QQitemZ220231342830QQihZ012QQcategoryZ39783QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
    - This your Bush?
    Pioneer Elite Sc-25
    Polk Lsic,15's,9's, PSW1000
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  • ben62670
    ben62670 Posts: 15,969
    edited May 2008
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    Its a very fine amp, and may only need a fuse, but if it is blown it can be very expensive to fix. That amp will toast nearly any receiver out there. You should be able to find one for around $200. Don't get hung up on watts with quaility amps.
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • dcmeigs
    dcmeigs Posts: 708
    edited May 2008
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    It may be something very easy to fix -- we've never had it looked at??!!

    I would take that statement with a grain of salt.
    The world is full of answers, some are right and some are wrong. - Neil Young
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  • Frank840
    Frank840 Posts: 262
    edited May 2008
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    Thanks for the help guys.

    I ownly bid 55bucks on it it has local pickup on it about 10miles from my house so for 50 buck if i were to win i think it worth getting looked at.
    - This your Bush?
    Pioneer Elite Sc-25
    Polk Lsic,15's,9's, PSW1000
    · Share on Facebook
  • ViperZ
    ViperZ Posts: 2,046
    edited May 2008
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    Frank, if you win it and can't fix it, I'll buy it from you and will pay for shipping ;).
    Panasonic PT-AE4000U projector for movies
    Carada 106" Precision Series (Classic Cinema White)
    Denon AVR-X3600H pre/pro
    Outlaw 770 7-channel amplifier
    B&W CDM1-SE fronts
    B&W CDM-CNT center
    B&W CDM1 rears on MoPADs
    JBL SP8CII in-ceiling height speakers
    Samsung DTB-H260F OTA HDTV tuner
    DUAL NHT SubTwo subwoofers
    Oppo BDP-93 Blu-Ray player
    Belkin PF60 Power Center
    Harmony 1100 RF remote with RF extender
    Sony XBR-X950G 55" 4K HDR Smart TV + PS3 in the living room
    · Share on Facebook