8ohm vs 4ohm on Rogue Integrated

Does it matter greatly what tap I have the Rogue Cronus Magnum 2 running on?

I had it on the 8 ohm tap while running the SDA 2a's and the Epos Epics which are both 4ohm speakers. Sound was fine and power seemed adequate. I've been using it this way for about a month.

Yesterday with the 2a's, after about an hour at moderate volume the Rogue went into protect. So I popped the lid and changed the taps (which was a fairly reasonable PITA) to 4ohm.

I'm assuming this is appropriate, however, if I want to run an 8ohm speaker, do I need to switch it back over to the 8ohm tap?

Thanks,
Paul
2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A

Comments

  • displayname
    displayname Posts: 1,126
    It's not always a clean cut answer, but the general rule is if your amp omh setting is equal to or lower than the speakers you're fine.

    4ohm speakers into 8ohm amp = bad
    8ohm speakers into 4ohm amp = fine

    Again, a general rule, not gospel.
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  • mhardy6647
    mhardy6647 Posts: 32,926
    edited January 2020
    So -- don't forget that the nominal impedance of most loads is just that... nominal.

    Here's the impedance curve of a loudspeaker rated by its manufacturer as "compatible with 8 ohm outputs", for example :)

    5976eg2avrai.png
    https://www.stereophile.com/content/polk-lsiiim703-loudspeaker-measurements
    (the impedance trace is the solid line; the phase trace is the dashed line)

    Neither Stereophile nor I would call it an 8 ohm speaker -- would you?
    And no matter what you'd call it -- what tap would you run it on? Probably the one that sounded better to you :)

    My recommendation would be run whatever speakers you want to run on whichever taps sound better to you.

    The only 'harm' that will result could be less power and or higher levels of distortion delivered to the load from a mismatched tap -- there may be little, no, or positive consequences in terms of the sound. :|

  • Mike Reeter
    Mike Reeter Posts: 4,314
    edited January 2020
    FWIW, A call to Rogue when I first purchased the Cronus, explaining that my speakers were a 6 ohm load and wondering which tap to use. Nick replied "whichever sounds best".

    I powered the SDA's with the 4 ohm tap, with no problems.
  • hochpt21
    hochpt21 Posts: 5,423
    An e-mail reply from Rogue before I ever used the 2a's said that the Cronus was common ground and should work well with the SDA's.

    Further, most of the information I could find on the 4ohm vs 8 ohm stated that whatever sounds best is fine. Well then my amp shut down yesterday and I thought, maybe it does matter...at least with this amp/speaker combo.

    I'll run it on the 4 ohm and go from there.

    Mostly I just don't want to have to get in there and change it back if auditioning a pair of 8ohms.....
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
  • Mike Reeter
    Mike Reeter Posts: 4,314
    hochpt21 wrote: »
    An e-mail reply from Rogue before I ever used the 2a's said that the Cronus was common ground and should work well with the SDA's.

    Further, most of the information I could find on the 4ohm vs 8 ohm stated that whatever sounds best is fine. Well then my amp shut down yesterday and I thought, maybe it does matter...at least with this amp/speaker combo.

    I'll run it on the 4 ohm and go from there.

    Mostly I just don't want to have to get in there and change it back if auditioning a pair of 8ohms.....

    I hear ya, changing those taps from 4 to 8ohm (or visa versa) is a PAIN, especially if you have big hands and big fingers to go along with them :#

  • smglbrth
    smglbrth Posts: 1,458
    If those are the same 2A's you got from me (via Don) they do run below 4 ohms with the newer crossovers/inductors. 3-3.5 if memory serves...
    Remember, when you're running from something, you're running to something...-me
  • delkal
    delkal Posts: 764
    mhardy6647 wrote: »
    So -- don't forget that the nominal impedance of most loads is just that... nominal.

    Here's the impedance curve of a loudspeaker rated by its manufacturer as "compatible with 8 ohm outputs", for example :)

    5976eg2avrai.png
    https://www.stereophile.com/content/polk-lsiiim703-loudspeaker-measurements
    (the impedance trace is the solid line; the phase trace is the dashed line)

    That part where the impedance drops below 4 and the phase angle drops to -45 is a double whammy. DO NOT Play a 70-90 Hz test tone loudly with these speakers.

    I would use the 4 ohm tap.
  • hochpt21
    hochpt21 Posts: 5,423
    smglbrth wrote: »
    If those are the same 2A's you got from me (via Don) they do run below 4 ohms with the newer crossovers/inductors. 3-3.5 if memory serves...

    I was looking back at our original conversations and saw that. I’m finally starting to focus on this system so your baby’s are getting some much needed attention. :)
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
  • hochpt21
    hochpt21 Posts: 5,423
    Well she’s been humming along on the 4 tap for 2+ hours with no problem now. Filled out the bottom end a bit more.

    And then I added a new SVS sealed sub, so the bottom end hath done been solidified.

    I came down here to test it a couple hours ago, but I’m kinda just stuck in this chair.

    :)
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A
  • GlennDog
    GlennDog Posts: 3,084
    hochpt21 wrote: »
    I came down here to test it a couple hours ago, but I’m kinda just stuck in this chair.
    :)

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  • yyzian
    yyzian Posts: 6
    I have the same integrated paired with Harbeth compact 7s which are 6 ohm rated. Connected to 8 ohm taps they went into protection couple of times. On the 4 ohm haven’t had any issues for the past 9+ months
  • hochpt21
    hochpt21 Posts: 5,423
    Good to know.

    I switched it to the 4ohm tap a couple months ago and no problems since.
    2 ChannelTurntable - VPI Classic 2/Ortofon 2M BlueAmplification - Rogue Audio Cronus Magnum II, Parks Audio Budgie PhonoSpeakers - GoldenEar Triton 17.2 Home TheaterDenon AVR-X3300W; Rotel RMB-1066; Klipsch RP-280F's, Klipsch RP-450C, Polk FXi3's, Polk RC60i; Dual SVS PB 2000's; BenQ HT2050; Elite Screens 120"Man CaveTurntable - Pro-Ject 2.9 Wood/Grado GoldAmplification - Dared SL2000a, McCormack DNA 0.5 DeluxeCD: Cambridge AudioSpeakers - Wharfedale Linton 85th Anniversary; LSiM 703; SDA 2A