Polk L800 amp question

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I finally made the 23 hour trip to get a set of mint condition L800 that had like 20 hours on it or so. I had a question on an Amp, currently I have a Adcom 5802 (300) more in 4 ohms, on the Goldenear Triton one.R, and the Adcom 555 iI on the Polk L800 and a Adcom 545 Polk vanishing 70s and Polk 5 jr in the kitchen. This system is in the living room with a Sunfire preamp. Question is the Polk l800 not compatible with the Adcom 5802 as I wanted to put more power on them vs the 555 and switch speaker wire over from the Goldenears but when I turned on the amp with the polks it was a loud scratching horn sound so I turned off the amp right away as I worried I would blow the amp or speakers so I put it back with the 555 running the polks. Thinking I read some amps not compatible due to SDA. Just curious as I wanted to give the Polk more power as the Goldenears have a sub amp in them.

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  • Viking64
    Viking64 Posts: 7,713
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    As difficult as those L800s can be to place for optimum sound quality, that couch and that chair have the potential to wreak havoc. Is this how you plan to have them set up permanently?
  • Polkrt3000
    Polkrt3000 Posts: 44
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    Not necessarily the permanent setup, but not a lot of options
  • Polkrt3000
    Polkrt3000 Posts: 44
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    I could move one speaker to the other side of the stereo rack but not a lot of options
  • pitdogg2
    pitdogg2 Posts: 27,597
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    Some amps are NOT compatible, true. The biggest problems were with balanced/differential topographies. I had an adcom 5802 It's a beast of an amp. My Aragon 8008bb blew it out of the water. From the sounds of it it does sound that that amp is not compatible.
  • Emlyn
    Emlyn Posts: 4,876
    edited June 6
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    The Adcom GFA-5802 is a dual mono design internally. Usually those designs are not compatible with the L800s. The 5802 is also not a common ground design.
  • invalid
    invalid Posts: 1,552
    edited June 6
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    I'm not positive on this, but I'm pretty sure the 5802 has differential outputs, even if you were using the single ended inputs. It seems like the amplifier started to oscillate when trying to drive the L800's.
  • nooshinjohn
    nooshinjohn Posts: 26,068
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    Emlyn wrote: »
    The Adcom GFA-5802 is a dual mono design internally. Usually those designs are not compatible with the L800s. The 5802 is also not a common ground design.

    You no longer need to worry about common ground non-common ground amplifiers with SDA in the L 800s. The only amp that offers a challenge, balanced differential designs.
    The Gear... Carver "Statement" Mono-blocks, Mcintosh C2800 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon MiND2 Shunyata Triton/Typhon Rotel RP9400 Turntable

    “When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson


    How many flies need to be buzzing a dead horse before you guys stop beating it?
  • Polkrt3000
    Polkrt3000 Posts: 44
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    So are you saying I don’t need to worry about a common ground on L800 and it should work with the 5802 or not, as others said it won’t work
  • Polkrt3000
    Polkrt3000 Posts: 44
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    Also would it make sense to bi amp it with say a Sunfire grand 5 channel 200 per channel in 8 ohms and higher in 4 ohms or would it not really be worth the money for a used one say around 700-800 range vs the 555 iI Adcom, or maybe get a second Adcom 555 in the future
  • F1nut
    F1nut Posts: 52,173
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    They are telling you the 5802 won't work because it has a dual differential topology.
    Also would it make sense to bi amp
    NO!!!

    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • invalid
    invalid Posts: 1,552
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    F1nut wrote: »
    They are telling you the 5802 won't work because it has a dual differential topology.
    Also would it make sense to bi amp
    NO!!!

    Even if it doesn't have a differential output, it's still sending the amplifier in to oscillation, which means it isn't compatible with the L800. I agree on the biamp idea, waste of time.
  • Polkrt3000
    Polkrt3000 Posts: 44
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    Ok thanks for letting know, I won’t biamp them, I did on my downstairs SDA 1.2tl I put two 555ii one for highs and lows, not sure if really made a difference. And use the 565 mono blocks on the back RT3000. Guessing I could of been fine with just one 555ii
  • Polkrt3000
    Polkrt3000 Posts: 44
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    Also guessing you guys are right on 5802 adcom so I will not use it. Thanks just double checking. As I almost pulled the trigger on a sunfire grand and guessing it would not make them sound any better by using 4 of the 5 channels for biamp so say 400 per speaker so a waste of money.
  • F1nut
    F1nut Posts: 52,173
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    It's less about wpc than it is amperes (current) that makes a difference. Since not all manufacturers list that spec a good way to tell is if the 8 ohm rating doubles at 4 ohm.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Polkrt3000
    Polkrt3000 Posts: 44
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    When guy mentioned an Aragon 8008bb Mayne out my price point but maybe someday, anyone think it would be worth going with a Sunfire Stereo amp vs grand cinema vs Adcom 555ii or not much change and maybe just save my money to drive L800, I’m not sure if the Sunfire would work either. I can just keep it the way it is for now.
  • Polkrt3000
    Polkrt3000 Posts: 44
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    Sorry for the typos, noticed after I posted
  • F1nut
    F1nut Posts: 52,173
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    The Sunfire is a decent amp. No idea of the topology though.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Polkrt3000
    Polkrt3000 Posts: 44
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    Ok is there somewhere a list of Amps that work well with the L800 just curious
  • nooshinjohn
    nooshinjohn Posts: 26,068
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    The Gear... Carver "Statement" Mono-blocks, Mcintosh C2800 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon MiND2 Shunyata Triton/Typhon Rotel RP9400 Turntable

    “When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson


    How many flies need to be buzzing a dead horse before you guys stop beating it?
  • F1nut
    F1nut Posts: 52,173
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    Polkrt3000 wrote: »
    Ok is there somewhere a list of Amps that work well with the L800 just curious

    Not to my knowledge.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • mpitogo
    mpitogo Posts: 523
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    I can’t believe it’ll be almost 7 years owning the L800’s. I have my pair bi-amp and using SDA compatible McIntosh MA5200 for the treble and MC452 for the bass. Unfortunately even the MA5200 is a bit underpowered, the power guard lights come in occasionally.
    • Living Room Music-2.1 Polk Legend L800 | SVS SB1000Pro | McIntosh C70 | McIntosh MA5200 (Treble) | McIntosh MC452 (Bass) | Sublimeacoustic K231 Active xover | Denon DP-2500A | Denafrips Ares II | Marantz HD-CD1 | Belkin Soundform Connect | iPad Pro USB to DAC
    • Home Theater-9.7.6/15.1 (Atmos/Auro-3D) Polk LSiM707, LSiM706c, LSiM702 F/X [x6], Height LSiM703 [x6], HSU ULS-15Mk2x4, VTF-15HMk2x2, VTF-TN1 | Trinnov Altitude 16+4 (2024) | Rotel RB-1590 (L/R) | Appollon NC500 11ch | Martin Logan MP500x2 | Topping DX7s, E50 | AppleTV 4K | Zidoo Z9X | JVC RS2100 | 150” Elite Screen Acoustic Pro UHD
    • Game Room-5.1 Polk LSi25, LSiC, LSiF/X | Marantz SR7009 | AppleTV 4K | Sony UBP-X800 | Xbox One S | Sony PS2, PS3 | Nintendo Wii | Gaming PC | Sony 75" LCD
    • Master Bedroom Music-2.0 Totem Hawk | Marantz PM-10 | Marantz SA-10 | SONY PS-HX500
    • Office-2.1 B&W Formation Duo and Bass
    • Daughter's Gaming Rig-2.0 Ascend Acoustics Sierra LX | Martin Logan Forte
    • Orphans DSW microPRO3000x2 | Rotel RA-1570 | Marantz AV8805A
    • Guest Room 2-2.0 Klipsch RP-600M | SMSL DO100 Pro 2 | Pass ACA v1.6 Monoblocks
    • Guest Room 3-3.0 Martin Logan Motion 40, 50XT | Onkyo TX-SR705 | Apple TV | Samsung 55" TV
    • Guest Room 4-2.0 QAcoustics 3030i | Sansui AU-6900 | Sansui FR-1080 | Fire TV
    • Maintenance: Pro-Ject VC-S Record Cleaning Machine
  • Emlyn
    Emlyn Posts: 4,876
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    The Parasound A21 or A21+ is usually a good all-purpose two channel amp used suggestion but the A21+ no longer appears as a new product on their website. The JC5 is a more expensive option that's still available. Too bad the company appears to be being run into the ground by discontinuing key products with no replacement models ready. Not sure I'd recommend buying anything new from them for now.