Amps with Series speaker outputs?

Discussion in 'Amps and Cabs [BG]' started by rumblethump, Jul 3, 2008.

  1. Being an owner of a MusicMan HD 130 amp that has series speaker outputs, I have found that this configuration is much more versatile when adding additional cabs.

    Are there any other amps out there that have this speaker output configuration?
  2. jz0h4d


    Apr 26, 2005
    Eden Nemesis.

    I totally disagree with it being "much more versatile".
  3. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    Very few amps have series outputs. The Nemesis combos are the only ones I've heard of recently.

    Depending on the configuration of the combo (minimum impedance limit and its internal speaker), series may be the only way to go. In that case the series connection is the only way you can go.

    I consider versatility to mean you have lots of options. In this case you wouldn't.
  4. JTE

    JTE Gold Supporting Member

    Mar 12, 2008
    Central Illinois, USA
    The versatility is that you can use the series output on the amp in additon to the parallel outputs on speaker cabinets to tailor different final loads. The HD-130 allows that because it also has an impedance selector to toggle between 4 and 8 ohms.

    So, I could hook hook two 8-ohm cabinets together using the parallel jacks on the cabs, into one of the amp's jacks, and run another 4-ohm cabinet off the other amp jack, setting the transformer to 8 ohms. Or I could run the one -4 ohm box off the amp, etc.

    I can see with the Nemesis combo that's not a useful option.

  5. Jazzman


    Nov 26, 2002
    Raleigh, NC
    The Ampeg B-15N has the two outputs wired in series.
  6. BassmanPaul

    BassmanPaul Inactive

    The internal speaker is one and the External jack is the other. The external jack also switches to the 16Ω tap to compensate.

  7. I've found by parallel wiring 2 cabinets (daisy chained), you can run either 4 8 ohm cabinets or 4 4 ohm cabinets at one time no problem. Having the coil tap switch makes this possible. I don't know of any parallel speaker output wired amp that can do this and am wondering why more amp makers haven't figured this out?

    Thanks for the tip on the Nemesis.
  8. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    One possible reason is that the 3dB gain you get by adding drivers stops at 6dB due to acoustic cancellation effects. Point of diminishing returns, perhaps.

    And combo amps tend to be marketed to players who generally aren't going to add cabs.
  9. anderbass


    Dec 20, 2005
    Phoenix. Az.
    A series speaker connection option could be easly added to most any amp.

    Here's a link to high quality Y-cord adaptor to obtain a series speaker connection with amp/cab-pairs using 1/4" jacks:

    Here's one I built out of an old 1/4" speaker cord and a couple heavy-duty 1/4" speaker jacks:


    The 1/4" series Y-cord speaker adaptor wiring is actually fairly simple, here's how its done:

    The male 1/4" positive (tip) goes to the first female jacks positive terminal.
    Then just loop that first female jacks negative terminal over to the second female jacks positive.
    The second female jacks negative then connects to the male 1/4" ground. (sleeve)

    (Just make sure you use quality speaker grade plugs/jacks and
    use 16 gauge or preferably larger wire for higher powered amps)