Any risks when putting a weak tubehead on top of a powerful sealed cabinet?

[Jens Busck]

Hi everyone,

I'm hoping for a little information from someone with a better gear-knowledge than mine (which propably includes pretty much all active members in here).

I'm thinking about purchasing a Bergantino NV412 since I like 12"-speakers and dislike tweeters, and it seems to be really popular in this forum.

In the long run I'm also planning to get a powerful head, but right now I'm using an Ampeg V4BH (100w), and I intend to use this with the Bergantino cabinet until I find the right replacement.

So my question is, if this temporary V4BH/NV412-combination will be likely to cause any damage to either amp or cabinet? I know that 100w-heads and sealed 4x12-cabinets have a history (like Bassman 100 or Ampeg V4), but what worries me is the crazy power rating of the NV412 - 800 watts! Should I be worried?

Perhaps I should add that I mostly play a hollowbody with overdrive pedals, oftenly pushing the V4BH to its limit (my current cabinet is an Ampeg SVT-15E).

I'd be thankful for any comment.

Greetings,
Jens (Denmark)

[4-string]

No problem, just make sure you select the correct impedance for the cab, which is 4 Ohms for the Berg I believe.

[cchorney]

Power rating of the amp doesn't matter, actual power drawn from the amp does... so keep the volume and eq reasonable and you should be fine. It helps in cases like this if you run a clean signal, as you can just trust your ears. If you are one of those "distortion bass" folks, I guess I would just caution you to err well on the side of caution here.

D'oh! I misread the OP. Low wattage head going into high wattage rating cab. I should have said "search the forums this has been covered before". Boy wouldn't that have been a better answer lol!

[billfitzmaurice]

Originally Posted by Jens Busck

what worries me is the crazy power rating of the NV412 - 800 watts! Should I be worried?

Worried about what? Don't even think about bringing up any 'underpowering' piffle.

I'm hoping for a little information from someone with a better gear-knowledge than mine (which propably includes pretty much all active members in here).

Time spent here would be a wise investment:
AMPS FAQ!! Info on OHMS, Allsize RIGS-OverUnderPowerCabs DIY TechTalk-Links

[nashvillebill]

??? (cchorney's post)

An 8 ohm cab rated 800 watts isn't going to "draw" any more power than an 8 ohm cab rated 200 watts.

An analogy: your kid weighs 50 lbs. You tie a tire up to a tree for him to swing on, with a rope that breaks at 500 lbs. Does your kid suddenly weigh 500 lbs? Nope, that's merely the point at which the rope breaks. You could use a rope rated 100 lbs, or 500, or 5000....the kid still weighs 50 lbs.

A speaker cab's power rating is an indication of how much power the cab can withstand before the speakers malfunction. Put an 8 watt amp on a cab rated 800 watts, the amp will still merrily put out only 8 watts (assuming the impedance is correct). If it can put out 8 clean watts before clipping into an 8 ohm dummy load, it still will put out 8 clean watts before clipping into an 8 ohm speaker cab rated 800 watts.

[nutdog]

Crank it. You'll be glad you did.

[PSPookie]

Originally Posted by nutdog

Crank it. You'll be glad you did.

This x ∞

You're on your way to a seriously sweet rig.

[CL400Peavey]

Originally Posted by nashvillebill

??? (cchorney's post)

An 8 ohm cab rated 800 watts isn't going to "draw" any more power than an 8 ohm cab rated 200 watts.

An analogy: your kid weighs 50 lbs. You tie a tire up to a tree for him to swing on, with a rope that breaks at 500 lbs. Does your kid suddenly weigh 500 lbs? Nope, that's merely the point at which the rope breaks. You could use a rope rated 100 lbs, or 500, or 5000....the kid still weighs 50 lbs.

A speaker cab's power rating is an indication of how much power the cab can withstand before the speakers malfunction. Put an 8 watt amp on a cab rated 800 watts, the amp will still merrily put out only 8 watts (assuming the impedance is correct). If it can put out 8 clean watts before clipping into an 8 ohm dummy load, it still will put out 8 clean watts before clipping into an 8 ohm speaker cab rated 800 watts.

I dont disagree with with the meaning of your statement, but your analogy is off. The tension forces felt by the rope with something hanging from it vs. something swinging from it are greatly different. In the stationary case the only forces are caused by acceleration due to gravity. In the case where the swing is moving there are other forces to take into account.

Either way crank that amp!

[NGJBeaner]

I run a 100 watt Pignose B100V tube head into a 400 watt Eden can all day. Sounds fantastic! Crank that Ampeg up and enjoy :-)

[nashvillebill]

Originally Posted by CL400Peavey

I dont disagree with with the meaning of your statement, but your analogy is off. The tension forces felt by the rope with something hanging from it vs. something swinging from it are greatly different. In the stationary case the only forces are caused by acceleration due to gravity. In the case where the swing is moving there are other forces to take into account.

Either way crank that amp!

Okay, I should've added the disclaimer: under static conditions; neglecting dynamic (centripetal) forces

[CL400Peavey]

Originally Posted by nashvillebill

Okay, I should've added the disclaimer: under static conditions; neglecting dynamic (centripetal) forces

sorry physicist at work... I almost wanted to give a more indepth explanation, but I EFFing hate accelerating reference frames.

[NGJBeaner]

I'm still trying to figure out when an Ampeg V4 started being considered "weak"?!?

[CL400Peavey]

Originally Posted by NGJBeaner

I'm still trying to figure out when an Ampeg V4 started being considered "weak"?!?

Its "only" 100 watts. In the world of kilo watt power supplies most people see it as a weak amp not realizing the power vs. sound output line is not linear.

[NGJBeaner]

Originally Posted by CL400Peavey

Its "only" 100 watts. In the world of kilo watt power supplies most people see it as a weak amp not realizing the power vs. sound output line is not linear.

I can't wait till the day people understand wattage over perceived volume.

[AdamR]

Originally Posted by NGJBeaner

I can't wait till the day people understand wattage over perceived volume.

It will never happen, wattage sells.

[CL400Peavey]

Originally Posted by NGJBeaner

I can't wait till the day people understand wattage over perceived volume.

I will admit you get more clean headroom with higher wattage amps, but that doesnt mean you get more volume. Look at the hundreds of threads that outline that you get more volume from more speakers, and still there are "how loud will I be if put 1.21 gigawatts through a 110 cab?" These thread pop up daily.

[NGJBeaner]

Originally Posted by AdamR

It will never happen, wattage sells.

True! I couldnt tell you how many times ive heard "you gig with that? It's only 400 watts!" (as I'm shaking the bar)

[CL400Peavey]

Originally Posted by NGJBeaner

True! I couldnt tell you how many times ive heard "you gig with that? It's only 400 watts!" (as I'm shaking the bar)

I hear that too, then I tell them to go pick up the 100 lb head...

In all seriousness I wish I could get something with the output of a fEARfull 1515/66 in 8 Ohms. I would like two of them up and let people know that anything over 300 watts is overkill if you have the speakers to back it up.

[NGJBeaner]

Originally Posted by CL400Peavey

I will admit you get more clean headroom with higher wattage amps, but that doesnt mean you get more volume. Look at the hundreds of threads that outline that you get more volume from more speakers, and still there are "how loud will I be if put 1.21 gigawatts through a 110 cab?" These thread pop up daily.

I've heard some crappy sounding hi wattage amps. Its about quality! Not quantity.

[will33]

Beautiful overdrive at a sane volume is one possible outcome........