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Ampeg Head and Cab Pairing Question (Need help understanding Ohms)

RustyNails

RustyNails

Guest
Jul 22, 2015
243
298
Las Vegas
#1
Hiya! I have an Ampeg Portaflex 500 Head which is 500 watts @ 4 Ohms. I'm running it through an SVT 4x10 cab that is 8 Ohms. My questions are

1.) Am I losing power by pairing these two together? Is it half the power it should be? Because it seems quiet on stage with my loud punk rock band.
2.) Would adding a second 8 Ohm 4x10 cab of the same model bring me back to the full power?
3.) Or would I be better off getting a different head (like the SVT head that I should be using which is @ 8 Ohms)

It sounds good, I just feel like my bass rig is underpowered for the gigs we play (small-medium size bars and clubs and house parties mostly that may or may not have DI capabilities running to the PA. It's about 50/50)

Speaking of DI boxes, if I can get plugged into one and run my bass through the PA it's fine for the audience but most places we play don't have monitors so I have to use the actual amp to hear myself which is not loud enough on stage.

I'm actually not even playing bass right now in a band anymore since we broke up a few months ago. i'm playing guitar in a different punk band now, but I would like to know for future reference what my next step is with this rig. Thanks!


EDIT: Fixed the numbers
 
Last edited:
#6
Off to a bad start. I fixed the numbers in the original post

Deezer Butler said:
The Portaflex 500 is 500 watts @ 4 ohm and 350 watts @ 8 ohm. Are you sure the cab is 4 ohm?
Click to expand...
The cab is 8 Ohms
B-string said:
If you have a 4 ohm cab with the PF-500 you are getting 500 watts potential from the amp head and you can NOT add any more cabs.
Click to expand...
The cab is 8 Ohms
Waltsdog said:
The PF500 can't run two 4ohm cabs - 2x 4ohms = 2 ohms
What does your eq look like?
Click to expand...
The PF500 is 4 Ohms, the cab is 8 Ohms, my fault. Fixed it.
 
#8
As above if your 4x10 is 8Ohm then add another cab.
Still worth telling us what your EQ looks like as you may have enough volume as is. But boosting lows too much will suck power and cutting mids will get you lost in the mix most of the time.
 
#10
Deezer Butler said:
Right now, your 8 ohm is only opening up 350 watts. A 2nd cab at 8 ohms will make it 4 ohms and allow your amp to run at 500watts. ...
Click to expand...

Waltsdog said:
As above if your 4x10 is 8Ohm then add another cab.
Still worth telling us what your EQ looks like as you may have enough volume as is. But boosting lows too much will suck power and cutting mids will get you lost in the mix most of the time.
Click to expand...

samson3382 said:
And a second 8ohm 410 like you have is gonna be significantly louder.
Click to expand...

Thanks M80s. That answers my questions. Now for another one: what if I did my 4x10 cab with a 1x15 cab at 8 Ohms? Good idea? Bad idea? Better off with a second 4x10? Also my EQ is usually high on mids (maybe 3 O'clock) and noon for bass and treble. give or take
 
#11
Okay cool you can expand the speaker count (makes things much louder than the bump in wattage 8 to 4 ohms). Your settings are still important and don't be afraid to run the gain high. 350 watts into a 410 should be really loud, only use the "pad" switch if you get distortion or have a solid peak light you can't tame. Just for info, at 350 watts to get twice as loud into the same speaker count you would need 3,500 watts from your current 350 watts. Speaker count gets you there much faster and easier.
 
#18
I had a similar situation as you. I was running an 8 Ohm 4x10 cab with an amp that put out about 500w @ 4 ohms and about 350w @ 8 ohms. I mainly play without PA support and this setup wasn't cutting it for me. I ended up upgrading to an amp with 1000w @ 4 ohms and 600w @ 8 ohms. I upgraded the cab to an SVT610. More speakers and it is 4 ohm.

If I were in your position I would look at ditching the 4x10 and getting either a 6x10 or 8x10. It all depends on what you can transport but for m
 
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#19
RustyNails said:
Hiya! I have an Ampeg Portaflex 500 Head which is 500 watts @ 4 Ohms. I'm running it through an SVT 4x10 cab that is 8 Ohms. My questions are

1.) Am I losing power by pairing these two together? Is it half the power it should be? Because it seems quiet on stage with my loud punk rock band.
2.) Would adding a second 8 Ohm 4x10 cab of the same model bring me back to the full power?
3.) Or would I be better off getting a different head (like the SVT head that I should be using which is @ 8 Ohms)

It sounds good, I just feel like my bass rig is underpowered for the gigs we play (small-medium size bars and clubs and house parties mostly that may or may not have DI capabilities running to the PA. It's about 50/50)

Speaking of DI boxes, if I can get plugged into one and run my bass through the PA it's fine for the audience but most places we play don't have monitors so I have to use the actual amp to hear myself which is not loud enough on stage.

I'm actually not even playing bass right now in a band anymore since we broke up a few months ago. i'm playing guitar in a different punk band now, but I would like to know for future reference what my next step is with this rig. Thanks!


EDIT: Fixed the numbers
Click to expand...

1.) Yes. The amp will not put out 500W at 8ohms. It will probably put out about half the power.
2.)Yes, adding a second 8 ohm cab will make the total load on the amp 4ohms. Therefore the amp will put out 500W into 4 ohms.
3.) No, that won't make a difference if your cab is 8 ohms. If you are looking for more volume, adding more speakers will do more than adding more power from a different head.
 

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