amp for lsi 15

speedy76speedy76 Posts: 2
Let me begin by saying that what I know about ohms, amperes, and GE lightbulbs could fill a thimble.

I inherited (free) a lovely pair of Polk Lsi 15m speakers and a non functioning Marantz 2270 receiver and a functioning Yamaha RX 586. I already owned a Sony 7.1 DN 860, and a Sansui TU 9900 presently used with my Sonus Faber Grand pianos. I will attach a subwoofer to my Polk in due time.

The issue of 4 ohm versus 8 ohm confuses and scares me. Which receiver should I be using and which amp, if any, should I look for? Is tube a better choice for classical music and opera? Do I need a pre-amp as well? I don't want to go cheap but not very expensive either. Thank you in advance.

Comments

  • FestYboyFestYboy Posts: 2,528
    Oh my, well I think starting with basics. Load (as seen by the amp) is measured by ohms. Using a resistor, the amp will see a steady load (relative to it's temperature), but a speaker presents a dynamic load and can (does in many cases) dip far lower than their DC resistance or impedance measurement (also listed in ohms). In this case, the lower the number, the greater the load on the amp. It's a bit confusing because as the number drops, the amount of current that can pass through the load (in this case, the speaker) goes up because there's less resistance, but in this case, lower resistance is bad because all the current has to pass through the amp as well and it has it's thermal limits. Think of it like this: the closer you get to 0, the closer you are to welding, which as you know means ALOT of heat.

    So, you want to have an amp that is stable to the lowest limits of the speaker you plan on using. Some 8 ohm speakers can dip to less than half that number (SDAs come to mind). That's why you'll hear want for a high current amp that is 4 ohm stable. They can handle the thermal load and can drive the speakers to their capabilities.

    The tube vs solid state debate has no affect on the above statements.

    Then there's the confusion with receiver, amps, pre amps... Unless you're looking for a specific sound, mixing receivers, amps and pre amps will cause more headache. A receiver is an all in one option. Everything but the source is in it: pre amp, volume control, amplification. An amplifier needs a pre amp for source and volume control.

    The LSi 15s shouldn't need additional sub reinforcement.
  • tonybtonyb Posts: 29,315
    Neither the Yamaha or the Sony will be able to drive the LSI's. What you need is either a receiver with preouts to add an amplifier, or a pre amp/amp combination. Depending on if this system will be for music or HT...OR BOTH.
    HT SYSTEM-
    Pioneer elite vhx 21
    Sony 4k BRP
    Tad 803 bookies
    Polk 500 surrounds
    Polk s35 center
    SVS SB-2000
    Sonos

    Music-

    Joule la-100 pre
    B&k 1403 amp
    Cary xciter dac
    Cullen modded Sonos
    ERA D5 bookies

    Cables-
    Acoustic zen Satori speaker cables
    Analysis plus crystal oval ic's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable
  • mrlorenmrloren Posts: 1,409
    Welcome to the Club,

    What Tony said. You will need an amp with either a good AVR that has pre-outs or a preamp. It's all about how much you want to spend and how big of a system do you want.
    When I was a kid my parents told me to turn it down. Now I'm an adult and my kids tell me to turn it down.

    Family Room:
    Samsung UN60H,
    Marantz SR5010, Emotiva BasX-A300
    Oppo BDP-93,Sony UBP-X800BM, Sony DVP-NS3100ES, WD Live HUB.
    Main: Polk Signature S60
    Center: Polk CSi-A6
    Front High TC80i
    Rear: Polk 80 F/X RT
    Sub: HSU VTF3-MK5

    Bed Room;
    Sony KDF-E42A10,
    Marantz SR5010, BDP-S270
    Main: Polk Signature S20
    Center: Polk Signature S35
    Rear: Polk R15
    Sub: HSU STF-2

    Working Warehouse;
    Sony 2100ES
    Polk RTi4 about 15' up the wall
    Old sony 12" Sub
    Mini tower PC with 400GB of music
  • speedy76speedy76 Posts: 2
    thank you all for your advice. I have ordered the hegel 160 pre amp/amp, and the NAD C427 FM tuner.

    here is a very silly question. As I had said, I have recently inherited these lovely speakers, and I was reading the manual on the internet as to how they should be positioned. If each speaker is considered a left or a right, where does the side speaker (woofer) face, toward each other or facing the outside walls? I think I have them reversed! Thanks everyone, more silly questions to follow I am sure.
  • mlistens03mlistens03 Posts: 1,405
    edited March 20
    Outside walls if they are the same as the 25s. The tweeters face in towards you. Look on the back near the serial number and it will say something like model LSi15 R (or L, depending on which one you look at).
    Edit: I was wrong before, it will look like this except it will say 15 instead of 25:
    87hujvxpfypd.jpg
    2 channel
    Speakers: Mission 770 Freedoms
    Integrated amp: Technics SU-v75 and matching tuner
    CDP: Technics SL-PC20
    Cables: Monoprice, Monster, Acoustic Research, and a few generic ones
    TT: Technics SL-3200, direct drive
    Cartridge: Shure M97xE

    Pc gaming setup
    Receiver/amp: Yamaha RX-V665
    Computer: Lenovo g50 (soon to be upgraded to a Dell Precision 690 which is far from stock!!)
    Interconnects: Amazon basics HDMI, Acoustic Research HDMI, Monoprice speaker cables
    Speakers: Boston Acoustics CR75s

    Random equipment on standby:
    Onkyo TX-v940, JBL woofers and tweeters, single Klipsch KG .5, Yamaha guitar amplifier, Peavey Rage 158 guitar amplifier, Kicker comp 12” subwoofer, single Bose 802 series II, a whole bunch of 1”-3” full range drivers, Infinity Crescendo 3007s (on sale), Polk LSi25s
    txcoastal1 wrote: »

    You don't tell her you read the manual, and you tell her you know what the problem is, and you fixed it, because that what men do, fix things
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