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I need a hookup advice please.

Discussion in 'Amps and Cabs [BG]' started by arekkoz, Dec 7, 2012.

  1. arekkoz


    Oct 5, 2011
    Let me list the gear first:
    AMP1: Ampeg SVT B2R
    AMP2: Ampeg Portaflex 500
    CAB1: Ampeg SVT 410HEN (8ohm)
    CAB2: Ampeg SVT 410HLF (4ohm)

    The venue is medium size bar where 400W should do the trick, and I want to keep it simple and "bullet proof".

    What's the best way to connect them for a gig?
    Speakon from amp to CAB1, and then Speakon from CAB1 to CAB2, keep AMP2 as backup.

    1/4" cords to each CAB directly from the AMP1, keep AMP2 as backup.

    Bass to AMP1 and then CAB1, also from AMP1 preamp to AMP2 "Power amp in", and then AMP2 to CAB2.

    AMP1 and CAB1, keeping AMP2 and CAB2 as backup.

    I will be selling/trading the CAB1 and getting one to match CAB2 (4ohm).

    Why do I have mismatched cabs?
    I bought the 410HEN to leave it at our practice place, while using smaller amp at home.
    Then I found good deal on Portaflex with 410HLF and got it without realizing that there is mismatch.
    In the past I have used my 810, but sold it.
    Now I have gig coming this Saturday, have both 410 together and noticed the difference.

    I don't think hooking them up OPTION1 would be a problem since the minimum impedance has to be above 4ohm (8+4)/2=6

    Let me know.....
  2. astack

    astack Supporting Member

    Nov 12, 2011
    St. Louis, MO
    Well buy her a drink first... ;)

    I'd say pick one amp and one cab that best fits the style. Bring the other amp as a backup if you'd like. "Medium bar" should be fine with just a 4x10, IME and IMO.

    Re: your ohm's calculation, the "divide by two" shortcut only works with the same impedance on each cab. The full equation is: R1*R2/(R1+R2), which in your case comes out to 2.66. No good for your heads unless they can do 2 ohms fine.
  3. christw

    christw Get low!

    May 11, 2008
    Dayton OH
    I want to be Tesla (tinkerer at Dayton Amp Co)
    No! You're doing that math wrong. Running cab 1 & 2 in parallel will net a result of ~2.67 ohms which is definitely not cool for the PF500. I'll reply in more detail if I sober up... ;)
  4. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    plug the PF500 into each cab by itself and compare; use that head with the better-sounding cab at the gig, and leave the rest at home.
  5. christw

    christw Get low!

    May 11, 2008
    Dayton OH
    I want to be Tesla (tinkerer at Dayton Amp Co)
  6. stiles72


    Mar 20, 2009
    Albany IL
    Take the B2RE head and the 410HLF as your rig. Leave the 410HE at home. The B2RE has more flexibility for tone shaping than the PF, and it is a time proven design. That will give you 450 watts at 4 ohms. Throw the PF500 head in your cord bag, back pack, laptop bag, or whatever you use since the PF is lightweight and will easily fit. That way you have it as a backup if needed.
  7. Gearhead17

    Gearhead17 Supporting Member

    May 4, 2006
    Roselle, IL
    I am not a big fan of the 410hlf, but this quote sums it up nicely. Roll the bass knob on the B2RE to the noon position or lower. Adjust the EQ so you do not push a lot 150hz and below. This will allow you to get louder and keep the low end in check. With the 410hlf, you have to watch your low end content. The cab pounds low end without needing a boost ANYWHERE.
  8. arekkoz


    Oct 5, 2011
    That's what I wil do.
    B2R and HLF.
    That will let me use the max power of the amp since it is 4 ohm.
    I will take PF as backup and leave HEN at home.
    Thanks for advice.

    If I ever need more power, should I use B2R as main amp, use preamp out to connect it to PF power amp in, and then separate cabs to each amp?
    That would give me 750W, but what's more important if one amp or cab goes down, I can rely on the second one.
  9. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    i suggested the PF as the main amp because it's more powerful. the B2 is only 350w at 4Ω vs 500w for the PF.

    the idea of automatically bringing a backup head is always a good one, though, and the B2 isn't gonna fit in a gig bag.