Max Volume from Ampeg V4 = two efficient 4 ohm cabs @ 2 ohm setting on amp?

[turunturun]

So I was hoping the experts here would weigh in on my current understanding and add in bits I am overlooking if possible....I want know how to get the most volume from my Ampeg V4 - primarily so I can have the option of getting some good clean headroom over a very loud drummer. I am currently getting the nice mild overdriven bass sound in spades. But that doesn't fit the bill for all styles.

1) The Ampeg V4 has an 8 ohm, 4 ohm and 2 ohm position switch. All other factors being equal, running the amp at 2 ohm will produce the most volume right?

2) Assuming they are both 4 ohms and of equal efficiency, the cabinet with more speaker surface area will produce more volume right? So a 4 ohm 2x15 will be louder than a 4 ohm 1x15, again assuming that the total speaker efficiency was the same. Right?

3) the greater the efficiency of the cabinet, the greater the effective loudness right?

So that would lead me to believe that this would be the correct path the maximizing the volume my V4 is capable of:
- run two 4 ohm cabinets and use the 2 ohm setting on the amp head
- make sure the cabinets have the most speaker surface area (ie a 4x10 has 197 sq inches, 2x15 has 148, a 2x12 has 118.4...not factoring the surround or whatever). Not necessarily considering tone or sound imparted by different speakers, here but just talking theory about maximizing volume.
- make sure the cabinets/speakers are the most efficient that I can find.

Yeah?

So a tag-on question. I have read some comments here or there about "Make sure you don't push it too hard when running on the 2 ohm setting with a fuzz pedal full on"....if 2 ohm is the max winding of the output transformer and the amp is designed to put it out, that statement doesn't make a whole lot of sense....am I missing something?

Thanks!

 

[billfitzmaurice]

Correct, more or less. Driver surface area is moot. The number of drivers used is key. A pair of Fridges would do nicely.

 

[GrowlerBox]

So a tag-on question. I have read some comments here or there about "Make sure you don't push it too hard when running on the 2 ohm setting with a fuzz pedal full on"....if 2 ohm is the max winding of the output transformer and the amp is designed to put it out, that statement doesn't make a whole lot of sense....am I missing something?

Thanks!

The lower the impedance the head is run at, the higher the current that passes through the power section, and the more heat generated. I suspect that's what the commentators you quote are getting at.

 

[DaZombieWoof]

With an output transformer the power output is the same at any of the impedance settings, unlike solid state. Want to move lots of air. effiient cabs are key. V4B amount of power can get stupid loud driving a lot of speakers.

 

[poor_gear_whore]

With the v4 you will get the same output in watts at 2/4/8 ohms. Bill is correct, the number of drivers used is the key to increasing you volume.

 

[nysbob]

I play one through a pair of very efficient JBL 15"s - never had a problem keeping up with any drummer. Mine's a four ohm load, I can imagine adding another pair of 15"s would be hellacious.

 

[turunturun]

Very helpful, thanks gents. Though I am confused to the response that speaker surface are is moot. I was under the impression that given the same signal, efficiency, and impedence, a 15" speaker will be louder than a 10" speaker - aka moving more air. In that sense it would seem as though surface area = amount of air moved. All other things being equal of course.

Am I missing something?

 

[lazyone2]

get a fridge, be happy

 

[billfitzmaurice]

All other things being equal of course.

Am I missing something?

In most cases a 1x15 will have more sensitivity than a 1x12, which will have more sensitivity than a 1x10. But seldom if ever will a 1x15 have more sensitivity, or even as much sensitivity, as a 2x10. All other things being equal, of course.

 

[Korladis]

Get two 8x10"s.

 

[turunturun]

Just as a matter of closing the loop here, got an 8ohm Avatar B212 with ceramics and did a tube replacement.....and now I have to run it at about -6 to -12db on my effects unit to sit correctly in the mix. Volume and clean headroom are no problem at all anymore....in fact the guitarist and I marvel at the fact that its only a quartet of 6L6s in there.
When I first got it I was disappointed at the lack of clean headroom, but that turned out to be a couple tired old tubes.
In the meantime (before a tube swap) I got in the habit of running the bass into a TC Nova System, then the line out of the Nova into the Ext Amp In on the V4...then I use the main volume on the Nova to control level....that works great and gives up plenty clean headroom. It is totally bypassing the V4 preamp section, but gives up some great power tube character. It can sound pristine and punchy, or kicking in a hot compressor patch or distortion and will send it to grind city.
After the tube refresh I tried going in the front again, and it was a totally different game than before. Plenty of clean headroom, in fact too loud for the mix (which includes a very heavy handed drummer, but a guitarist that declared a volume-war truce long ago).
So I am happy to say that I am now in the "no problem keeping up with a loud drummer with my V4" camp.

But the moral to the post is......I wonder if I should find out what the two fridges can do for me !!!!!

 

[anderbass]

Cool, I just love stories with a happy ending.