Amp Gain Questions

[fatboytyler]

I have a JVC KW500 that has preamps rated at 2.5 Volts. I run a Rockford Fosgate R1200 amp. Where should I have the gain set in order to safely avoid clipping? I am confused on how to exactly read the gain knob.

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[Staynlean 10+ year member]

Use search function, there's MULTIPLE threads about how to do this. Gains on the amp are there to match the output power of the source. So , there's a little math involved and you need a DMM at minimum, to accomplish this. You could do a quick google search of setting amp gains and it will bring you right back to the respective thread on this site.

Sorry, too lazy and drunk to link it for you. If you don't know how to do it, you have a lot to learn. But, it is easy. Search it man, get those gain settings done correctly.

Also, a lot of the threads you will read do not mention that the vehicle needs to be running and warmed up, I.E. The battery is not taking a charge from the alternator any more and you are running at your vehicles average voltage. Just crank it, let it sit for 5 mins then to about the process.

 

[bbeljefe]

The input sensitivity on that amp is 150mV-4 volts so that's about a five volt spread between full counter and clockwise. You can suppose that to be right at half way but that's not necessarily the case and improper gain setting is the single most common reason for sub/amp failure... so I'd take the advice above.

If you have questions after doing some due diligence, I'm happy to help.

 

[fatboytyler]

Use search function, there's MULTIPLE threads about how to do this. Gains on the amp are there to match the output power of the source. So , there's a little math involved and you need a DMM at minimum, to accomplish this. You could do a quick google search of setting amp gains and it will bring you right back to the respective thread on this site.
Sorry, too lazy and drunk to link it for you. If you don't know how to do it, you have a lot to learn. But, it is easy. Search it man, get those gain settings done correctly.

Also, a lot of the threads you will read do not mention that the vehicle needs to be running and warmed up, I.E. The battery is not taking a charge from the alternator any more and you are running at your vehicles average voltage. Just crank it, let it sit for 5 mins then to about the process.

I did use the search function, bbeljefe answered the most important question I was looking for and that was the scale of the gain knob on my amp. I read the manuals and browsed various other places trying to find it with no avail.

I mainly wanted to know roughly, by eye balling where to set my gain. I'll drag out my DMM later on today and double check everything.

And thank you both!

 

[fatboytyler]

So the voltage my speaker can handle is the Sq Root of the ( RMS Wattage * the Ohms ) ? So if my speakers are 200 RMS at 4 Ohms they should be able to handle 28 Volts without any problem at all correct?

 

[fish1234 10+ year member]

Correct, Sir.

 

[bbeljefe]

So the voltage my speaker can handle is the Sq Root of the ( RMS Wattage * the Ohms ) ? So if my speakers are 200 RMS at 4 Ohms they should be able to handle 28 Volts without any problem at all correct?

Not technically correct. Your sub can handle 28 volts from an unclipped wave form. Matter of fact, it can probably handle 50 volts if the wave form isn't clipped. What it can't handle is a clipped waveform and that can happen at any voltage. And you can't read whether the waveform is clipped with a DMM.

That said, you should be fine with how you're doing things but do keep an eye on the sub(s) and make sure they don't get hot when you're wanging on it. If they don't, then you're safe.

 

[fatboytyler]

Well I have my gain set to a level that should be well under the clipping point. It's only turned about a 1/3 of the way. I could go more, but I would rather stay on the safe side.

 

[Side Show 10+ year member]

^^ always recommemnded

 

[fatboytyler]

Well I took it to a local shop today and hooked it to a SMD Clipping tool and I was darned close with guesstimating it with a DMM. I should get a line driver in Wednesday so I can crank the gain up without worries and prepare me for 600W RMS as compared to 200 //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[jrdnhsnbrg 10+ year member]

Well I took it to a local shop today and hooked it to a SMD Clipping tool and I was darned close with guesstimating it with a DMM. I should get a line driver in Wednesday so I can crank the gain up without worries and prepare me for 600W RMS as compared to 200 //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Uh, no, a line driver won't let you do that. If it's barely clipping at 200W you're going to blow your sub faster than you can blink.

 

[fatboytyler]

Its not clipping? I had the gain set too high, causing clipping at higher volume. I just hooked it to a clipping device and set the gain so that it would not clip at 40/50 volume.

 

[jrdnhsnbrg 10+ year member]

Its not clipping? I had the gain set too high, causing clipping at higher volume. I just hooked it to a clipping device and set the gain so that it would not clip at 40/50 volume.

A line driver won't let you boost your power like that though

 

[fatboytyler]

The line driver will allow me to boost gain without clipping though correct? I obviously run the risk of overpowering the subs, but as long as I stay within a safe voltage range I should be fine correct?

 

[jrdnhsnbrg 10+ year member]

The line driver will allow me to boost gain without clipping though correct? I obviously run the risk of overpowering the subs, but as long as I stay within a safe voltage range I should be fine correct?

Hahahaha, no it will not by any means.