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Differing Ohm Load Ampeg Cabs

P

Pickinator

Dec 28, 2011
93
34
Eagle River WI
#1
I have the opportunity to buy an Ampeg stack with a 4X10 and a 1X15. The 1X15 is rated as 8 Ohm (200 watt) and the 4X10 is rated at 4 Ohm (400 watt). The Ampeg head is rated at 500 watts, but not at all Ohm loads.

Can the system run with differing Ohm load cabs?
Will the head read a total Ohm load of:
3.464 (square root of 12 {4 + 8})?

Forgive me if I'm off Base (get it) :D with my math or worried about Ohm loads unnecessarily.

The amp was sold together as a package at a music store, but that probably doesn't mean much. I am looking to use this set up for the living room and possibly small clubs someday if I make the purchase. It is lightly used and was made in America.
 
#3
Pickinator said:
I have the opportunity to buy an Ampeg stack with a 4X10 and a 1X15. The 1X15 is rated as 8 Ohm (200 watt) and the 4X10 is rated at 4 Ohm (400 watt). The Ampeg head is rated at 500 watts, but not at all Ohm loads.

Can the system run with differing Ohm load cabs?
Will the head read a total Ohm load of:
3.464 (square root of 12 {4 + 8})?

Forgive me if I'm off Base (get it) :D with my math or worried about Ohm loads unnecessarily.

The amp was sold together as a package at a music store, but that probably doesn't mean much. I am looking to use this set up for the living room and possibly small clubs someday if I make the purchase. It is lightly used and was made in America.
Click to expand...
Bolded is incorrect. That is not how you calculate total impedance of parallel components.
 
#5
RickenBoogie said:
The good news is that IF you were to run a 15 with a 410, they should be @ the impedance your 2 cabs are. The bad news, 8 ohms plus 4 ohms equals 2.67 ohms, so your amp would need to be 2 ohm stable.
Click to expand...

I'm with him on this.

Which specific Ampeg cabs are they? I ask because if the 4 ohm 410 is the SVT-410HLF, I don't think you'll get much synergy between that cab and a 15; I think it's best to run that cab on its own or with another one of the same cabs.
 
#6
The amp head is the B5r and it's tech specs read:
675 watts @ 2 Ohms (500 watts continuous)
380 watts @ 4 Ohms (310 watts continuous)
200 watts @ 8 Ohms (180 watts continuous)

The Cabs are:
BSE 115 T
BSE 410 HLF

I believe the 115 is rated for 200 watts and the 410 is rated for 400 watts. Each cab has a horn in it too.

Is this bass package a mess or can it work. I'm looking at $600 for the works.

How is the Ohm load of the 2 cabs combined determined. I thought it would be the square root of the combined 4 + 8 thereby the square root of 12? (about 3.464....). Again, please forgive my ignorance; I'm still learning. And I'm a drummer.

Thanks for the input (get it):D
 
#14
oboylebass said:
According to Ampeg's website, running 2 cabs, each with different loads (impedances) is NOT RECOMMENDED.

Don't do it!
Click to expand...

I would imagine that's due to uneven power distribution. In this, you'd want uneven distribution with the 15 recieving the least power, or better yet, leave the 15 out all together. The HLF is already a very deep sounding cab, the only thing a 15 would hope to add to the blend would be if it was a very bright sounding 15, adding response the 410 doesn't have. It'd be best to run the 410 by itself. One reason to buy the whole stack would be so you could leave the 15 at a separate location, like a rehearsal space to be played by itself....just carry the amp back and forth.
 
#15
Unfortunately, it all comes as a package for $600.

Could a guy buy a new 15" 4 ohm Ampeg speaker and swap it with the 8 Ohm that's in it. If so, how much would it cost and any recommendations on where to purchase. Is it an easy job to change the speakers?

Would this sound good?:bassist:
 
#20
$600 is a good deal for that collection of gear; just think of it as a half-stack rig with a 15 thrown in for other uses.

sell the 15, keep it in the practice space, use it for small gigs where that big ol' 4x10 would be too much, whatever. (were it me, i'd sell the 4x10, get another 15, and rock 2 15s old-school.)
 

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