Posted: 1/4/2017 2:24:57 PM EDT
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I've been trying to get more headroom out of my SWR Electric Blue head (120w @ 8ohms) to keep up with the drummer and guitars, and decided to use a slave power amp between the head and my 410 cabinet (400w@8ohm).
Trouble is, I seem to keep frying power amps after a few years. First it was a Mackie FRS 800, then a 1000w Crown. Am I having bad luck or trying to do the impossible? Should I look at a bass power amp? I love the tone of my head...just want it louder. Thanks |
| You can't get more headroom out of that amp. What cab are you currently using? Your best bet would be to add a second 4x10 8ohm cab. I'm guessing your using the SWR as a pre amp (bass into the amp input, then out from the effects loop to the power amp and cab connected to power amp)? |
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The 410 is an SWR also. Workingman's series with a horn.
I've been running from the balanced XLR out, not the effects loop on the Electric Blue into the input of a power amp. Could that be the reason I'm blowing up power amps? Perhaps I given the wrong information years ago on setting up my rig. I did try plugging my old Ampeg 15 into the extension speaker jack yesterday and it did run quite a bit louder. It'll be fine for my basement but I don't want to lug 2 100 lb cabinets to every gig. How can I slave a power amp without blowing it up? |
Yeah, headroom and volume are not the same thing. If you want more volume out of that set up you're going to need more speakers. You could have a 1.21 gigawatt power amp, but it won't be any louder with just your one 4x10 cab. I'm kind of surprised you haven't blown the cab.
As for frying the power amp, it all depends on the output of the pre amp. Some XLR outputs don't have a volume control and come out full volume. Usually that is why you send the unbalanced line out signal to drive the power amp. With your set up, and wanting more volume out of it, I'm guessing you have the gain dimed? Probably clipping the pre amp pretty good. I'm not familiar with that head though. Is it a tube or solid state pre? |
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Quoted:
There is nothing wrong with going from the XLR out of a bass head to a power amp. What do you think is happens when a sound guy uses it to run into the PA? You're definitely correct, that way of running the signal should be fine. I was just thinking out loud. I've had more than one power amp go just because it felt it was it's time to go. |
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Thanks for the responses. The amp has a tube preamp, and the gain is usually set around1100, so I only clip when I really dig in. The balanced XLR out that I run into the power amp does have a knob (they call it a pad) which I run at full.
So is the consensus that I just had bad luck with the mackie and the crown? Would a bass specific power amp be better? |
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Quoted:
Thanks for the responses. The amp has a tube preamp, and the gain is usually set around1100, so I only clip when I really dig in. The balanced XLR out that I run into the power amp does have a knob (they call it a pad) which I run at full. So is the consensus that I just had bad luck with the mackie and the crown? Would a bass specific power amp be better? If I were you, I'd take the power amps to a good repair tech and ask him what's happening. They can probably be fixed. You're off track with the "bass specific" power amp idea. I seriously doubt that your problems have anything to do with bass. Any good power amp will amplify electric bass just as well as any other instrument or fart noise. |
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Quoted:
Boo this man! Can you be my roadie  ? First beer is on me!
I'm going to pick up one of those SWR 750 power amps and give it another whirl with just using the 410. I'll keep the Ampeg 15 in the basement. Arfcom never disappoints for great responses! Thanks guys |
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Quoted:
Can you be my roadie ? First beer is on me!
I'm going to pick up one of those SWR 750 power amps and give it another whirl with just using the 410. I'll keep the Ampeg 15 in the basement. Arfcom never disappoints for great responses! Thanks guys So you're ditching the Electric Blue? I thought you liked the tone you got from it. Why do you need a whole new head? It still seems like you're hung up on this idea that bass ruins regular ol' power amps. It doesn't. All you need is a good power amp that biggers the signal coming from the head you already have. That's all power amps do, they bigger the audio signal you send them, regardless of whether it's from a bass or a digeridoo or a full band. A good power amp will happily bigger the signal from your Electric Blue. Until it doesn't, that is, but power amps will eventually crap out no matter what you feed them. That said, for practical purposes you're probably making the right call in replacing the Electric Blue with a ballsier head. Just know that the power section of your new SWR 750 is just as liable to shit the bed as any "non bass specific" power amp at that price point. In terms of robustness, it is not magically superior to other power amps because it has the word bass on the front. Just wanna clear that up. Good luck 
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Thanks- I have no intention of ditching my Electric Blue. I was just wondering if the SWR power amp may be a more robust choice. Maybe I'll just go with another Crown that's new if there's no difference in bass handling capabilities.
I'd like to keep it around or under $500. I feel better knowing that there's no real difference. |
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Quoted:
Can you be my roadie ? First beer is on me!
I'm going to pick up one of those SWR 750 power amps and give it another whirl with just using the 410. I'll keep the Ampeg 15 in the basement. Arfcom never disappoints for great responses! Thanks guys Just get your gear on wheels. It saved my back. |
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Quoted:
Thanks- I have no intention of ditching my Electric Blue. I was just wondering if the SWR power amp may be a more robust choice. Maybe I'll just go with another Crown that's new if there's no difference in bass handling capabilities. I'd like to keep it around or under $500. I feel better knowing that there's no real difference. That's cool, man, just realize that cheap amps are cheap amps, whether they're bass heads or PA amps. It's your money, but this would be your third cheap power amp, right? Three $500 amps that last a few years apiece or one $1500 one that goes the distance...your call. |