Volume/Gain vs OHMS?

[Joe Z]

Greetings:

I'm familiar with most of the concepts and I've read most of the threads, but I haven't come across a definative statement on this issue.

Driving amps lower than the reccomended Ohms can lead to overheating, shutdown and damage. In my case, I've traded my SVT Pro IV for a Markbass Little Tube 800. I have two Ampeg 410HLF cabs (4 ohms).

With the SVT, each channnel was 4 ohms - two cabinets is no problem. Now, I'm running the 800 down to two ohms.

A friend of mine is a technician in the audio field and he said that if I don't push the gain/volume I won't have the problem. Keeping gain/volume down limits the power usage of the unit and will keep it from frying.

Ignoring the critical question of how do you know what's too much volume, would you agree that simply hooking up with 2 ohms is not the problem - it's only when you push too much power thru too little resistance that you beat up the amp and run the risks?

regards...Joe

[billfitzmaurice]

Originally Posted by Joe Z

would you agree that simply hooking up with 2 ohms is not the problem - it's only when you push too much power thru too little resistance that you beat up the amp and run the risks?

True. The problem lies in knowing how much power is too much. If your amp shuts down at 1/10 power due to excess current draw what have you gained by running too low an impedance load?

[lbwdog]

I certainly wouldn't take the chance. The manufacturer states it's minimum impedance for a reason!

A question. If you're keeping it turned way down, what's the purpose of a second cab anyway?

[EpiRipper]

Running an amp below its minimum impedance will generally fry output transformers pretty quick, due to excess current running through them. Been there, done that!

[KJung]

Originally Posted by lbwdog

I certainly wouldn't take the chance. The manufacturer states it's minimum impedance for a reason!

A question. If you're keeping it turned way down, what's the purpose of a second cab anyway?

+1 and +1

[RickenBoogie]

Yes to both the previous +1's, and a big +1. Just use one cab, or sell them both and settle on one 4 ohm or 2 8 ohm cabs.

[Joe Z]

thanks, guys... I'm looking at the Markbass 810 and a few other, including the Ampeg... I think I'll not take the risk!!!

Thanks again, as usual...best regards...Joe

[billfitzmaurice]

Originally Posted by EpiRipper

Running an amp below its minimum impedance will generally fry output transformers pretty quick!

Nope. SS amps have a minimum impedance load, tubes have a maximum impedance load. Tube amps typically short circuit the output transformer when there's no speaker plugged in, as no load will cause damage, a short won't, at least so long as you don't run it full tilt for a few hours that way.