#1

Heres the deal, i have an ampeg 4x10, and am happy with it, but I need a new head because the behringer im using is just sad, I think im going to go for a carvin bx1200. it seems perfect, lots of volume and tone options and a great price. I also want to get their eighteen inch speaker cab to give me low end definition, but the 1x18 is a 4 ohm cab and my ampeg is 8 ohms, would i be able to use both?

#2

Yes, yes you would. That would put the ohm rating at 2.666 ohms and the Carvin has a minimum impedance of 2 ohms. That'll do you fine. Although, I'm sure fitz'll bring this up too, you'll get an uneven sound. The bx1200 can't run 2 ohms in bridged which means you'll have to crossover or run it dual mono. That will result in 250 watts going to the 410 and 400 going to the 118. That means you won't have an even response.

#3

Yes, yes you would. That would put the ohm rating at 2.666 ohms and the Carvin has a minimum impedance of 2 ohms. That'll do you fine. Although, I'm sure fitz'll bring this up too, you'll get an uneven sound. The bx1200 can't run 2 ohms in bridged which means you'll have to crossover or run it dual mono. That will result in 250 watts going to the 410 and 400 going to the 118. That means you won't have an even response.

how do i run it over in crossover or dual mono? (im such a noob at these things) will i need to buy more things?

#4

You don't have to buy anything. You just need to plug in the cabs properly and then use the crossover knob.

#5

For mono-bridge (which you can't use anyway) you actually need a special cable (to get the power amps to run in series) which is just a Speakon with the pins swapped around, but you needn't worry about that anyway.

Jazzy's 100% correct. Plug your 410 into the high power amp, and plug your 118 into the low power amp (you'll see at the back). There should be a switch for crossover on and off - on if you want stereo, off if you want dual mono (which I actually prefer!).

You'll be getting 225W in the 410 and 400W to the 18. In dual mono, the unbalance isn't the end of the world, but in stereo mode, it's a ****ing nightmare. However, there's actually a volume control for both power amps. That means you can "match the volume" between the two cabs by boosting one/cutting the other/both. It's a necessity when having unbalanced cabs.

However, even though you can feign it, I don't recommend you do it like that long-term. You can do it for a while, but you'll eventually want a proper 4 ohm 410.

Jazzy's 100% correct. Plug your 410 into the high power amp, and plug your 118 into the low power amp (you'll see at the back). There should be a switch for crossover on and off - on if you want stereo, off if you want dual mono (which I actually prefer!).

You'll be getting 225W in the 410 and 400W to the 18. In dual mono, the unbalance isn't the end of the world, but in stereo mode, it's a ****ing nightmare. However, there's actually a volume control for both power amps. That means you can "match the volume" between the two cabs by boosting one/cutting the other/both. It's a necessity when having unbalanced cabs.

However, even though you can feign it, I don't recommend you do it like that long-term. You can do it for a while, but you'll eventually want a proper 4 ohm 410.

#6

so it can eventually cause damage because its an odd ohm match-up?For mono-bridge (which you can't use anyway) you actually need a special cable (to get the power amps to run in series) which is just a Speakon with the pins swapped around, but you needn't worry about that anyway.

Jazzy's 100% correct. Plug your 410 into the high power amp, and plug your 118 into the low power amp (you'll see at the back). There should be a switch for crossover on and off - on if you want stereo, off if you want dual mono (which I actually prefer!).

You'll be getting 225W in the 410 and 400W to the 18. In dual mono, the unbalance isn't the end of the world, but in stereo mode, it's a ****ing nightmare. However, there's actually a volume control for both power amps. That means you can "match the volume" between the two cabs by boosting one/cutting the other/both. It's a necessity when having unbalanced cabs.

However, even though you can feign it, I don't recommend you do it like that long-term. You can do it for a while, but you'll eventually want a proper 4 ohm 410.

#7

No damage. There are 2 power amps that run independantly (except in mono bridge mode). If you set it up in stereo or dual mono (1 cord per cab connecting to the head), you're gold.

#8

No damage. There are 2 power amps that run independantly (except in mono bridge mode). If you set it up in stereo or dual mono (1 cord per cab connecting to the head), you're gold.

okay, yeah, i saw the high and low inputs on the back on their site, and you said i can control each cabs volume individually?

#9

Yep, there should be a power amp volume for both power amps.

#10

Yep, there should be a power amp volume for both power amps.

okay, sorry, but one more question, will i be able to run in bridged mode to get all that volume? i dont fully understand all the mono and stereo stuff.

#11

Arg... I'll explain this as quickly as possible.

Running 2 power amps in mono or stereo is essentially running them in parallel. They're working 'side by side.' There not ACTUALLY parallel because they're totally independant, but think of them like parallel. You hook up each cab to it as if it were it's own amp. The difference between dual mono and stereo is that stereo splits the signal in 2.

Running 2 power amps in mono bridge is essentially running them in series. That is, one of the amps is basically hooked into the other and you get combined power.

In parallel, the impedences half every time you add another cab, but in series, the impedences double. For the power amps, it kinda works the same way.

The Carvin runs at 225W per side 8 ohm, 400W per side 4 ohm, and 600W per side 2 ohm. "Parallel."

Now, in mono-bridge, it runs at 800W at 8 ohm, and 1200W at 4 ohm. That is, you're essentially running BOTH power amps at 2 ohms (when getting the 1200W at 2 ohms), but since their hooked up in bridge mode ("series"), you'll be doubling the total impedence, therefore you're getting twice the power rating of half the impedence, doubled (since two power amps). 800W at 8 ohm bridge is 2 times the 400W at 4 ohm (but both power amps are actually running at 4 ohms each, but 8 combined). 1200W at 4 ohm bridge is 2 times 600W at 2 ohm (2 ohms each, but 4 combined). There is no 2 ohm bridge, since each power amp doesn't operate at 1 ohm. Ya dig?

So, basically, the answer is NO. Like I said before a few times, you'd have to run it in stereo or dual mono to get it to work... at all. Then, once again, you'll have to adjust the volumes, yadda yadda yadda. You cannot mono-bridge a 4 ohm and a 2 ohm - period. And even if you did, you'd be getting much more power out of one cab compared to the other, and you could NOT adjust the volume.

So, this is what you do:

1) Sell your Ampeg and get a 4 ohm 410 along with the 4 ohm 18 you want.

2) Buy an 8 ohm 18 or 15 from, say SWR, and run it in Mono Bridge (assuming both cabs handle 600W each).

3) Run it unbalanced (8 ohm, 4 ohm) until you can procure either another 8 ohm cab to pair with your existing 8 ohm (not really economical), or trade the 8 ohm for another 4 ohm, and run it in stereo or dual mono (totalling 800W of power)

4) Aquire four 4-ohm cabs, 2 per side, to get 1200W dual-mono or stereo

5) Keep it unbalanced. Not a good idea.

My recommendation would be to actually consider an 8 ohm sub cab and run it bridged as opposed to getting 2 four ohmers. But that's your call.

Oh, and FWIW, you need at least one cab with Speakon connectors to get mono-bridge working. Getting mono bridge requires a Speakon cable with the pins rearranged.

If any of this went over your head, you're not ready and/or need to read up on the subject.

Running 2 power amps in mono or stereo is essentially running them in parallel. They're working 'side by side.' There not ACTUALLY parallel because they're totally independant, but think of them like parallel. You hook up each cab to it as if it were it's own amp. The difference between dual mono and stereo is that stereo splits the signal in 2.

Running 2 power amps in mono bridge is essentially running them in series. That is, one of the amps is basically hooked into the other and you get combined power.

In parallel, the impedences half every time you add another cab, but in series, the impedences double. For the power amps, it kinda works the same way.

The Carvin runs at 225W per side 8 ohm, 400W per side 4 ohm, and 600W per side 2 ohm. "Parallel."

Now, in mono-bridge, it runs at 800W at 8 ohm, and 1200W at 4 ohm. That is, you're essentially running BOTH power amps at 2 ohms (when getting the 1200W at 2 ohms), but since their hooked up in bridge mode ("series"), you'll be doubling the total impedence, therefore you're getting twice the power rating of half the impedence, doubled (since two power amps). 800W at 8 ohm bridge is 2 times the 400W at 4 ohm (but both power amps are actually running at 4 ohms each, but 8 combined). 1200W at 4 ohm bridge is 2 times 600W at 2 ohm (2 ohms each, but 4 combined). There is no 2 ohm bridge, since each power amp doesn't operate at 1 ohm. Ya dig?

So, basically, the answer is NO. Like I said before a few times, you'd have to run it in stereo or dual mono to get it to work... at all. Then, once again, you'll have to adjust the volumes, yadda yadda yadda. You cannot mono-bridge a 4 ohm and a 2 ohm - period. And even if you did, you'd be getting much more power out of one cab compared to the other, and you could NOT adjust the volume.

So, this is what you do:

1) Sell your Ampeg and get a 4 ohm 410 along with the 4 ohm 18 you want.

2) Buy an 8 ohm 18 or 15 from, say SWR, and run it in Mono Bridge (assuming both cabs handle 600W each).

3) Run it unbalanced (8 ohm, 4 ohm) until you can procure either another 8 ohm cab to pair with your existing 8 ohm (not really economical), or trade the 8 ohm for another 4 ohm, and run it in stereo or dual mono (totalling 800W of power)

4) Aquire four 4-ohm cabs, 2 per side, to get 1200W dual-mono or stereo

5) Keep it unbalanced. Not a good idea.

My recommendation would be to actually consider an 8 ohm sub cab and run it bridged as opposed to getting 2 four ohmers. But that's your call.

Oh, and FWIW, you need at least one cab with Speakon connectors to get mono-bridge working. Getting mono bridge requires a Speakon cable with the pins rearranged.

If any of this went over your head, you're not ready and/or need to read up on the subject.

#12

thanks fitz, you should really get paid for all the help you give.

#13

thanks fitz, you should really get paid for all the help you give.

Yyyyyyyyyyyyep!