Voltage/Thermal Limiting

[wabbit]

What are you driving the power amp with, and what is the amps input sensitivity?

I am driving the amp with a Fractal AxeFX II preamp. According to the amp's specifications, the Input Sensitivity (volts RMS) is adjustable in 0.1V steps from 1.28V to 8V. I actually don't know at the moment what it's set at. When I get home from work today, I will hook it up and check and let you know.

Thanks for the response.

 

[JGR]

I have an Axe II and you should have no problems driving an amp. Have you tried the balanced XLR out? Might take some of the guesswork out and will minimize noise as well.

 

[wabbit]

I have an Axe II and you should have no problems driving an amp. Have you tried the balanced XLR out? Might take some of the guesswork out and will minimize noise as well.

I am driving the amp with the AxeFX output set to around 6 but the problem seems to be a lot less output from the Crown amp than expected. I am using the XLR balanced output from the Axe to the amp. Noise is not an issue. When I go to band practice, I hook the AxeFX into the provided backline amplifier's effects return loop and there's a TON of volume.

I appreciate the response though. Any more thoughts?

 

[BassmanPaul]

Sounds as if you're not putting enough signal out of the pre-amp to sufficiently drive your power amp. Crown tends to need higher levels than other makes.

 

[BassmanPaul]

How are you connecting your cabinets to the amp? Plus what are the amps AC requirements?

 

[Downunderwonder]

I am driving the amp with a Fractal AxeFX II preamp. According to the amp's specifications, the Input Sensitivity (volts RMS) is adjustable in 0.1V steps from 1.28V to 8V. I actually don't know at the moment what it's set at. When I get home from work today, I will hook it up and check and let you know.

Thanks for the response.

Big difference!

 

[wabbit]

How are you connecting your cabinets to the amp? Plus what are the amps AC requirements?

I am using Neutrik cables and have each cabinet hooked up to it's own channel from the amp making the impedance 4 ohms per channel.

The required AC mains for the amp is 100-240 VAC, 50/60 Hz.

Did those answer your questions or were you asking for something more specific?

 

[wabbit]

Big difference!

At the moment, the input sensitivity is set at 6.35V, 23.95dB with the Max Input set at +21dBu. I believe these are the defaults for the 'Custom' setting. I have two other non-customizable settings/choices at 26dB and 32dB that are available.

 

[thumbknuckle]

At the moment, the input sensitivity is set at 6.35V, 23.95dB with the Max Input set at +21dBu. I believe these are the defaults for the 'Custom' setting. I have two other non-customizable settings/choices at 26dB and 32dB that are available.

That's your problem. Nominal 'line level' is +4dBu, or about 1.2 VRMS.

 

[wabbit]

That's your problem. Nominal 'line level' is +4dBu, or about 1.2 VRMS.

Okay. Now we're getting somewhere. Thanks.

 

[BassmanPaul]

Wabbit, a standard 15A supply will deliver about 1800VA continuously. 4KW continuously isn't going to happen. That said your amp should be very loud indeed. Whereabouts in our fine city are you??

 

[wabbit]

Hey there fellow Torontonian. I didn't even notice. My bad.

I'm in the West end in the High Park area. And you?

Oh, and to your comment, the amp is actually meant to drive off of a 20A service but I don't usually see too many 20A plugs up on stage. I swapped out the 20A power cable and it's oddly angled blades with a regular 15A power cable.

 

[BassmanPaul]

Morningside and Ellesmere in Scarborough. As for the AC, remember that in use on the wrong supply you'll be able to trip the breaker with normal use.

 

[will33]

Set the Crown's input sensitivity down to the 1.28V setting and you should be good to go. I don't see any problem using the 15A supply. Just know that when you get towards pulling 1800 watts continuous from the wall, to include everything plugged into that circuit, the amp will start to sag/run out of gas or trip a breaker. Likely not an issue though, you should be deaf or have blown your speakers before that happens.