Ampeg 8x10 wiring...

Discussion in 'Amps [BG]' started by BobbyXIII, Jul 30, 2013.


  1. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    I could find an answer to this because I'm sure it sounds crazy but is there a way to wire 4 8 ohm speakers in the cab with 4 32 ohm speakers and still have the cab run at 4 ohms?
  2. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    Yes.

    Wire two 8 Ω speakers in series, then the other two 8 Ω speakers in series, then wire each pair in parallel. This will give you 8 Ω. (8 + 8) || (8 + 8) = 8 Ω

    Wire the four 32 Ω speakers in parallel. 32 || 32 || 32 ||32 = 8 Ω.

    Then wire each set in parallel. [(8 + 8) || (8 + 8)] || [32 || 32 || 32 ||32] = 8 || 8 = 4 Ω
  3. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    Awesome thanks so much. I was alittle misinformed about the ohms on speakers and was buying 32s when I needed 8s. You wouldn't happen to have a diagram by any chance or a drawing haha.
  4. john m

    john m Supporting Member

    Joined:
    Jan 15, 2006
    Will each speaker have the same current running through it?

    Will each speaker operate at the same wattage?

    Will the speakers all have the same volume?
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  6. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    It's gonna be 4 jensen mods that are 32 ohms and 4 of the original celestions which are 8 ohms.
  7. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    Here is hacked together diagram.



    [​IMG]


  8. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    Since you are mixing different speakers, if the specs are different, you may find one group of four louder than the other.

    Normally in an Ampeg 810, all speakers are 32 ohms and they are all wired in parallel.
  9. john m

    john m Supporting Member

    Joined:
    Jan 15, 2006
    The 8's will be louder than the 32's.
  10. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    Why will the 8's be louder than the 32's if they are all the same wattage and would that mean 4 would be louder than 8?
  11. Bass 45

    Bass 45 Supporting Member

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    Jun 23, 2011
    Location:
    Tempe, Arizona
    I think the 8 ohmers would have a higher sensitivity.

    Can you exchange the the Jensens for an 8 ohm model (then you can just use the existing wiring)?
  12. john m

    john m Supporting Member

    Joined:
    Jan 15, 2006
    There are two paths with 8 ohm speakers in series.
    That leg of the circuit is 16 ohms. 16 ohms will draw 2x the current as 32 ohms. Not sure how current relates to volume, but I know that the magnetic field is a function of current and number of turns of the coil.

    As someone mentioned, speaker sensitivity is also an important factor for volume.
  13. Vince Klortho

    Vince Klortho

    Joined:
    Jan 8, 2013
    Location:
    Squierville, California
    The 8Ω speakers will each get half the voltage and the 32Ω speakers will get full voltage. Each 8Ω will get one quarter of the current and each 32Ω speaker will get one eighth of the current.

    For the sake of illustration, let's say you drive it with a 400W amplifier. This means it will be putting out 10A and 40V into the 4Ω load. Each 8Ω speaker will get 50W and each 32Ω will get 50W.

    I don't know how the relative volumes will compare but I know that speaker excursion is proportional to voltage and the 8Ω speakers each get half as much voltage as the 32Ω speakers.

    BTW - for a series-parallel connection it is better to use two speakers in parallel that are in series with another pair of two in parallel. This is because in the wiring configuration shown, if one of the 8Ω speakers blow in an open circuit then its series mate will also stop working. In the configuration I mentioned, if one of them blows the other three in the S-P arrangement will continue working. This can be done by connecting one wire as shown in the attached illustration. This configuration will not change the current or voltage draws.

    Attached Files:

  14. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    I was studying that diagram an notice it is using 2 inputs for the back of that cab right? Well my 8x10 pro only has one input so how would that be wired?
  15. Vince Klortho

    Vince Klortho

    Joined:
    Jan 8, 2013
    Location:
    Squierville, California
    If you want just one input jack then omit the second jack and the wires connected to it. The second one is there to allow you to connect a cable to another cabinet. It is not required.
  16. john m

    john m Supporting Member

    Joined:
    Jan 15, 2006
    Doing the P=I squared *R the same wattage is delivered to each speaker.

    However, all things equal, my guess is that the 8 ohm speakers would be louder due to the excursion as mentioned.

    Safest to used all of the same speakers.


  17. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    What you are saying is correct but in an 810 with two drivers per sealed chamber, you also have to consider if it is better to run the cab as a 610 or a 710. Some feel that it is better to disconnect the good speaker and run it as a 610 because of the risk of damaging the good speaker due to over extension. See this thread. I feel that if you are pushing a lot of lows, running it at as a 610 if a speaker blows, is probably best.
  18. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    Finished all the wiring thanks for the help! I went with 2 eminence (32ohm) 2 jensen mod (32 ohms) and 4 celestion bg10h-150 (8 ohms) and I have to say it sounds fantastic.
    ImageUploadedByTalkBass1376039373.510275.jpg
  19. Bass 45

    Bass 45 Supporting Member

    Joined:
    Jun 23, 2011
    Location:
    Tempe, Arizona
    now cover them up before they get torn;)

    It that a V9 head/cab I see to the left there?
  20. BobbyXIII

    BobbyXIII

    Joined:
    Dec 11, 2011
    Yeah I have the baffle it's covered now haha. I'll eventually recover it in vintage ampeg clothe to match everything else. Good eyes too! Yeah that's my V9 head and cab which I'm super psyched about. It is just way too loud though haha. ImageUploadedByTalkBass1376041241.273572.jpg

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