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I recently got the chance to try my newly built Jack12 with my Peavey Max 700 at a rehersal studio.

At 8 ohm the Peavey should put out 275 watts but it seemed to be clipping early at about 7/10 on the master volume it did this with or without the ddt speaker protection, obviously with it on it just compressed the volume.
Is this normal for amplifiers or does it have a fault?
The speaker didn't seem to be struggling so i'm pretty sure it was all down to the amp, anyway i'm currently building a second Jack to give me 475 watts at 4 ohms so hopefully that will work better

thanks

'Hog

Once crossed over, my jacks and subs can handle all the power from my 402d which puts out 300@8ohm. The speakers are fine but I can tell the amp struggles, and even more so with your smaller amp. Sure 90% of the time it's putting out around 10-20volts but it's the peaks that make it clip, that's why I like to run 2x power than the speakers are rated for. Also, not that my jacks are loaded with the mcm driver which rated fro 150rms and I'm running the bp102 in my titans.

Of course, if you something that puts out double the power, it will be double the money and will only be slight louder, but it will not clip and will keep the integrity of the input signal.

Thanks for the reply, i was looking for an excuse to buy a lighter, more powerful amp!

My jack has the 2512 driver and I really felt like it could handle far more power than the peavey could give.

spacehog wrote:I recently got the chance to try my newly built Jack12 with my Peavey Max 700 at a rehersal studio.

At 8 ohm the Peavey should put out 275 watts but it seemed to be clipping early at about 7/10 on the master volume it did this with or without the ddt speaker protection, obviously with it on it just compressed the volume.
Is this normal for amplifiers or does it have a fault?
The speaker didn't seem to be struggling so i'm pretty sure it was all down to the amp, anyway i'm currently building a second Jack to give me 475 watts at 4 ohms so hopefully that will work better

thanks

'Hog

The master volume setting really could be any value as far as voltage in concerned.If it's clipping it could be from the pickups or at the input and you just dont notice it until you crank the master gain.What kind of bass and pickups are you using? You could simply measure the output voltage when you hit a string and see how much she is really dishing out. At least then you will know if it's in the pre or power section.

oops, thought he was talking about a pro amp, so listen to Ron.

@Ron

It was definitely power amp clipping because the peavey has a red light which shows when it's clipping, i also experimented with different preamp gain settings and know what that the preamp drive sounds like.
I was just surprised how easily it did it, although maybe i was just trying to get too much bass out of it?

Bass is a yamaha RBX375 5 string

cheers

'Hog

Got ya. I would measure the voltage output at clipping and see if it giving you a full 275 w. If it isn't then there's a problem within the amp. 5 string just pluck the low D and take the reading. That string should gobble up quite a bit of power especially if you box is running without a HPF to keep the sub lows from driving the driver into x-max or thermal limiting.

ok, forgive my ignorance but how do i calculate wattage from the voltage? wouldn't i also need to know the amps?

'Hog

I can never remember the calcultion so i work it out each time:

amps is voltage/impedance

power is voltage x amps

so power is volts squared/impedance

therefore whatever power you think you should be making for a given load muliply that by the given load and take the squareroot, that's your voltage.

Now be careful where you poke your voltmeter. 30 or 40 volts can jump and you don't want to ground your amp output or you'll have a lot more to worry about.

spacehog wrote:ok, forgive my ignorance but how do i calculate wattage from the voltage? wouldn't i also need to know the amps?

'Hog

http://www.the12volt.com/ohm/page2.asp