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Now I've tried to get my head around ohms etc and I thiiiiiiink i understand but I want to double check because I'm feeling pretty thick today and getting in a muddle.

I have a markbass TTE500. It's 500W at 4ohms/ 300W at 8ohms. I am borrowing an ampeg 4x10 SVT which is 500W at 8ohms for my upcoming tour. I would like to add an ampeg B-115E to this which is 200W at 8ohms. Will I be able to safely drive these cabs with my amp to their potential? I'm wondering if the 1x15 might be driven too hard.

Any wisdom or suggestions appreciated!

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  • We need more detail. How exactly will you be connecting the two cabinets to the amp? The level of detail needed is essentially "this cable will go from this plug to this plug, then this cable will go from this plug to this plug".
    – Todd Wilcox
    May 8, 2019 at 15:21
  • My amp has two speakon outputs, i usually just use one for an ampeg 8x10.
    – devil rides out
    May 8, 2019 at 15:23
  • And you plan to use a speakon cable to go from speakon output 1 to one cabinet, and then a separate cable to go from speakon output 2 to the other cabinet?
    – Todd Wilcox
    May 8, 2019 at 15:24
  • Yes you're quite right, apologies I've not used this site before. A simple setup of speakon output 1 to one cab and speakon output 2 to the other cab.
    – devil rides out
    May 8, 2019 at 15:34

1 Answer 1

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Looks like the safest assumption (since I can't find details on the Markbass site or the manual) is that the two speakON outputs on the TTE500 are wired in parallel.

What that means is that when you plug a separate 8 Ohm cabinet into both of the TTE500 speakON outs, you are presenting a total 4 Ohm load to the amp. That means the amp's rated output will be 500 Watts, although it's not clear whether that's peak or RMS. It could be RMS.

Now your total dissipation (again, probably RMS) between the two cabinets is 700 Watts, which is good, but the problem is that the power will be essentially divided evenly between the two cabs. That means if you run the amp full out, each cab will be asked to dissipate 250 Watts (approximately) and that could overdrive the B-115E.

You could look for a 1x15 with higher power capacity, you could use only the 4x10 SVT, or you could hook it up the way you plan to and just keep the amp fairly quiet. If you need a rig to be reliable for a whole tour, I personally wouldn't risk it.

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  • Fantastic, thorough, response. I really appreciate it. I think you're quite right and i need a 1x15 with a higher power capacity as I don't really fancy worrying about ruining a nice wee cab. Thanks so much again.
    – devil rides out
    May 8, 2019 at 15:39
  • @devilridesout My pleasure - always looking to help out with amp/cabinet matchups. You can also upvote the answer if it helped you. I won't get any rep from it (I've hit the cap today) but it will tell future users that the answer was valuable.
    – Todd Wilcox
    May 8, 2019 at 15:42
  • Assuming all wattages are RMS , that's only going to be 50 watts over for the 1x15. Is it only really going to be problematic if the amp is flat out? I'd guess that up to 7 (/10) would keep it safe.
    – Tim
    May 8, 2019 at 16:01
  • @Tim It really depends on a lot of factors. The power output is not linear with the volume knob, and the total power is related to the bandwidth of the signal, so kicking on a distortion pedal without changing the master volume at all can almost double the power. You're right that it's not only possible, it's arguably likely that the cabinet will be fine. The big question is how reliable do you want things to be for an entire tour.
    – Todd Wilcox
    May 8, 2019 at 17:07

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