Beta Bass impedance question (running 2 4 ohm cabs out of the back)

[snarzdar]

We played a show last night and I ran my beta bass out to 2 emperor 4 ohm cabs. One of the guys from Emperor said I was going to blow up my beta bass because I was dropping the cabinets down to 2 ohms. I thought that as long as I wasn't chaining the cabs together I wouldn't be messing with the load at all. Am I messing up my beta bass by running two 4 ohm cabinets out of the back?

For the record I normally run my beta bass to a beta 215 and sunn 610 straight out the back.

[equilibrium78]

When you hook up 2 cabs together the ohms drop in half.When you hook 2 cabs straight to any head,they are being hooked up it parallel which drops 2 4ohm cabs to 2 ohms. If you hook a 8ohm cab and a 4 ohm cab in back of the head it will run about 3.7ohms.
Inside the cabs you have they have 2 8ohm speaker hooked up in parallel making it a 8ohm cab. If you hook up the speakers in series in the cabs making it a 16ohms and hooked them both up to the head,then it will be running at 8ohms.

[rot gut]

If the beta bass is similar to the beta lead ohm-wise then yeah, you might ruin your beta bass. Running 2 4ohm cabs out of it makes it 2ohms, you should be running 4ohms minimum.

[snarzdar]

Yeah.. I just found the manual online. I read somewhere a while back that it had 2 different outputs. I was wrong. YIKES.

[EdBass]

Yeah.. I just found the manual online. I read somewhere a while back that it had 2 different outputs. I was wrong. YIKES.

For future reference, as far as this impedance discussion there can only be one actual output per amplifier circuit regardless of how many jacks there are. If there are multiple jacks they are connected to that single output either in parallel or series, and I can't think of a commercially available amp that has the jacks wired in series so I think it's generally safe to assume they are parallel.

For example; If your Beta actually had two separate outputs on the back, that weren't "chained" together, it would have to be two monaural amps, or stereo.

[Isaac]

When you hook up 2 cabs together the ohms drop in half.When you hook 2 cabs straight to any head,they are being hooked up it parallel which drops 2 4ohm cabs to 2 ohms. If you hook a 8ohm cab and a 4 ohm cab in back of the head it will run about 3.7ohms.
Inside the cabs you have they have 2 8ohm speaker hooked up in parallel making it a 8ohm cab. If you hook up the speakers in series in the cabs making it a 16ohms and hooked them both up to the head,then it will be running at 8ohms.

"If you hook a 8ohm cab and a 4 ohm cab in back of the head it will run about 3.7ohms."

Nope. 2.7 ohms.

[paco)))]

So running 2 - 4 ohm 2x15B cabs out of one output on a beta bass together is fine as long as one cable goes from the amp to speaker A then out of speaker A's other jack & into speaker B? That would be a 4 ohm load right? I just wanna get that clear before I blow something up

[EdBass]

Nope, same result as using both of the Beta's jacks. You would still be showing your Beta a 2 ohm load, the parallel connection between the two jacks in speaker A would parallel the cabs just like the parallel jacks in the Beta would.
Regardless of how many cabinets you use, your only viable options for impedance using four 8 ohm drivers are a 2, 8 or 32 ohm total load.
Your best bet would be to wire the drivers in the cabs in series, making each cab 16 ohms and showing the Beta an 8 ohm load and use the jacks on the Beta rather than "chaining" the cabs. Even though the amp would be running under peak 4 ohm power, it would be substantially louder than one cab at 4 ohms, and wouldn't fry your Beta.

[paco)))]

Yeah I might re-wire depending on what I find out about the coliseum head. I was planning on running that into the 2 - 2x15 cabs at a 2 ohm load since that amp can handle it but it just doesn't seem to have the power it should be putting out.

[paco)))]

I took the coliseum head to the shop but then I ran the beta bass into one 215B & my concert slave into the other 215B & HOLY HELL  Those cabs are awesome & that set up with a bass muff & my '80 ric 4001 is tits!