Just adjusted gain, 1 quick question.

[digitalrainman 10+ year member]

i just adjusted my gain on my amp for my kicker cvr 12 2ohm sub i just put in. The amp is a crunch amp that states it can do 450x1 @ 4ohm bridged. So for my calculation the voltage should be sqrt(400x4) = 40volts. I adjusted my gain to 40 volts by using a dmm on the speaker terminals. I only had to turn the gain knob 1/2 of the max. My question is, is this normal? The reason i am asking is because i was trying to push 400 watts out and the amp maxes at 450 rms, and i only turned it up halfway. I put it to full to get a voltage and it went to 69 volts, which would be 1190 watts. This sounds odd to me, but then again i am new.

Also another question was is this the correct formula i should have used sqrt(400x4), since i am running my dual 2 ohms on the sub in series and its providing a 4ohm to the amp?

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[Sunfire01 10+ year member]

The Gain knob is just adjusting the sensitivity to the HU's pre-out voltage. A higher pre-out voltage (or better HU in this case) would allow for a lower gain (or sensitivity) level to be set on the amp, and still achieve the volts (that you calculated at 40v for your crunch amp). At that 1190 watts you stated (gain @ max), it would clipping, since the amp is only rated to do 450w.

When you match the gain to the rated output watts of the amp at that certain ohm level, you prevent the amp from clipping. That is the whole point of using this formula.

hope it's clear to you.

 

[DDeitz 10+ year member]

dont mean to post dump, but then whats the point of having higher volt pre out as long as your amp will match the pre out level of the HU, it shoudnt make a diff then right?

 

[mapolley07 10+ year member]

same question here.....

and also, how do you figure the input voltage on the RCA's. I assume you connect the DMM to the RCA plugs, but which is positive and which negative?

is the inner contact pin positive and the outer ring negative on the RCA connector?

also, how do yo know which frequency test tone to set gains with?

 

[Sunfire01 10+ year member]

The gain on the amp would be able to be set lower, thus reducing noise in the system, and allowing the amp to run cooler with less stress.

to answer above^^ I believe you use a 1Khz for midrange, and a 50 or 60hz for monoblocks.

 

[mapolley07 10+ year member]

okay, thanks. so using a 1khz test tone would work for a comp set?

also I have heard that the 5V preout on my eclipse HU is overrated, and also I would have voltage drop over the RCA run. so how would I measure the input voltage?

okay here is an RCA connector ascii (o) a DMM has a positive and negative lead, obviously. So would I set it to measure AC voltage, positive on the center pin of the RCA [o] and the negative on the outer ring of the connector [( )]????

 

[luvinthebass 5,000+ posts]

okay, thanks. so using a 1khz test tone would work for a comp set?
also I have heard that the 5V preout on my eclipse HU is overrated, and also I would have voltage drop over the RCA run. so how would I measure the input voltage?

okay here is an RCA connector ascii (o) a DMM has a positive and negative lead, obviously. So would I set it to measure AC voltage, positive on the center pin of the RCA [o] and the negative on the outer ring of the connector [( )]????

a 1khz tone would work just fine

and yes put it to measure AC voltage and put the dmm leads on those.

 

[Death By Bass 10+ year member]

The gain on the amp would be able to be set lower, thus reducing noise in the system, and allowing the amp to run cooler with less stress.

WTF? lol, that just makes no sense

 

[phyphoestilic 5,000+ posts]

The gain on the amp would be able to be set lower, thus reducing noise in the system, and allowing the amp to run cooler with less stress.
to answer above^^ I believe you use a 1Khz for midrange, and a 50 or 60hz for monoblocks.

wow.... just wow...... //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[Sunfire01 10+ year member]

WTF? lol, that just makes no sense

I don't see how it makes no sense. When you run components at a cooler temperature, you lessen the chance of failure. I call the components "stressing" because I would be too if I was working in the sun compared to air conditioning temps //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif.(and no the lessened gain wouldn't be changing the temps that drastically, but there would be a difference) I was just trying to explain some advantages of lower gain, whether they be drastic or not.

oh- and maybe I don't type stuff exactly correct when re-read, I know I do this, but I think many got my point.