Connecting a subwoofer and speakers to a single output preamp?

Discussion in 'Speakers' started by AdvanTech, Aug 6, 2019.

  1. AdvanTech

    AdvanTech Friend

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    I recently acquired an Hsu Research ULS-15 mk2 subwoofer and have it connected via the RCA out of my Freya S while my speakers use the XLR out to my amp.

    After reading @sphinxvc’s thoughts on his Goldpoint vs. Freya S comparison with @Hooncake , I looked into how I can make one of those preamps work with my 2.1 setup. The only thing is that there’s only one hot output out of the Goldpoint.

    Someone at Goldpoint said I could use an XLR Y-splitter out of the preamp to go to the sub and speaker amp. I could also do speaker wire out of my amp to the sub, then another set of speaker wire out to my speakers. Which option is better? Or is there a 3rd option I’m not aware of?
     
    Last edited: Aug 6, 2019
  2. yotacowboy

    yotacowboy McRibs Kind of Guy

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    Use the amp's speaker outputs to feed the speakers, then either connect another pair of speaker cables from the speakers to the speaker input on the sub, or run a parallel set of speaker cables from the amp to the sub.
     
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  3. sphinxvc

    sphinxvc Gear Master (retired)

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  4. elmoe

    elmoe Friend

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    I'm single ended here, but I use a Y splitter to dual subs from my preamp for best results. This may depend on your gear though, as far as what sounds best.
     
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  5. purr1n

    purr1n Finding his inner redneck

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    If running two parallel pairs from the speaker outputs to the subwoofer speaker-level inputs, there should be no issue. The sub speaker-level input impedance is likely to be at least 20,000-ohms. Speaker loads are like single-digits. It's as if the amp doesn't even see anything else connected. Like if someone replaced a single steel screw with a titanium screw on your 29lbs bike - would you go up the hill any faster?

    Now one thing to be concerned about: monoblock amps with differential outputs = boom or safety shutdown. In the case of amps with differential output via OPTs, you would need to know which of the secondaries can be grounded.
     
  6. sphinxvc

    sphinxvc Gear Master (retired)

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    That's useful. Any impedance issues using a Y-splitter for line level to sub + power amp? The Goldpoint is completely passive. The input impedance of the sub for line level doesn't seem to be specified by the manufacturer, but it's one of those plate amp jobs.
     
  7. ultrabike

    ultrabike Measurbator - Admin

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    Should be fine as far as impedance.

    If the sub volume control is implemented prior to the amp gain stage inside the sub, then you also don't have to worry about clipping the sub pre-amp. Just adjust the volume control in the sub.

    EDIT: BTW, many subwoofers actually have "hot" inputs that are plugged directly to the speaker main L & R outputs of an amplifier using a Y-splitter. I did this in my father-in-laws case with a Polk 12" sub. This after the Monster RCA cable damaged the Pionner receiver's sub output port. It worked great using the L & R main speaker channels from the Pioneer receiver.
     
    Last edited: Aug 6, 2019
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  8. purr1n

    purr1n Finding his inner redneck

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    I think 10k-ohms or 20k-ohms is a good assumption for the input impedance of those plate amp jobs.

    As for Y-splitter from a passive volume control, it's hard to say. Let say it's 20k-ohms on the subwoofer input and 10k-ohms on the amp input. After Y-splitter, the collective input impedance is now suddenly 6.6k-ohms.
     
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  9. dBel84

    dBel84 Friend

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    agreed that for passive output splitter from the goldpoint - should be OK , even the impedance change will be not noticeable as you are intentionally putting this in series with the resistors in the stepped volume switch. any signal mismatch to sub relative to amp will be corrected by volume adjust on sub
     
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  10. Pogo

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  11. Walderstorn

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  12. elmoe

    elmoe Friend

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    I'm curious also, looks like a decent passive solution at a much better price than the Jensen ISO stuff
     
  13. Pogo

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