gain setting

[ledzeppac]

well I'm making this harder than it is...

I printed off a table that is used to set gains on my amp. Alpine f450 70x4

I have kicker comps that are rated at 60 watts rms so I used the 55 watts on the table. That said to tune to 14.8 volts. I tuned the amp to 14.5.... with 1khz

However, the amp gets very hot and shuts off. (alpine f450)
How do I go about diagnosing it?
Do I have a faulty amp, and that is what is screwing my tuning up. Or am I just retared? My coaxles that are in the back are much louder than the comps and they run off the HU.

Values for Common Speakers:
5 Watts -- 4 Ohms, V=4.47 -- 6 Ohms, V=5.47 -- 8 Ohms, V=6.32
10 Watts -- 4 Ohms, V=6.32 -- 6 Ohms, V=7.74 -- 8 Ohms, V=8.94
15 Watts -- 4 Ohms, V=7.74 -- 6 Ohms, V=9.48 -- 8 Ohms, V=10.95
20 Watts -- 4 Ohms, V=8.94 -- 6 Ohms, V=10.95 -- 8 Ohms, V=12.64
25 Watts -- 4 Ohms, V=10.0 -- 6 Ohms, V=12.24 -- 8 Ohms, V=14.14
30 Watts -- 4 Ohms, V=10.95 -- 6 Ohms, V=13.41 -- 8 Ohms, V=15.49
35 Watts -- 4 Ohms, V=11.83 -- 6 Ohms, V=14.49 -- 8 Ohms, V=16.73
40 Watts -- 4 Ohms, V=12.64 -- 6 Ohms, V=15.49 -- 8 Ohms, V=17.88
45 Watts -- 4 Ohms, V=13.41 -- 6 Ohms, V=16.43 -- 8 Ohms, V=18.97
50 Watts -- 4 Ohms, V=14.14 -- 6 Ohms, V=17.32 -- 8 Ohms, V=20.0
55 Watts -- 4 Ohms, V=14.83 -- 6 Ohms, V=18.16 -- 8 Ohms, V=20.97
60 Watts -- 4 Ohms, V=15.49 -- 6 Ohms, V=18.97 -- 8 Ohms, V=21.90
65 Watts -- 4 Ohms, V=16.12 -- 6 Ohms, V=19.74 -- 8 Ohms, V=22.80
70 Watts -- 4 Ohms, V=16.73 -- 6 Ohms, V=20.49 -- 8 Ohms, V=23.66

thanks Phil

 

[TURBOV6]

well I'm making this harder than it is...

I printed off a table that is used to set gains on my amp. Alpine f450 70x4

I have kicker comps that are rated at 60 watts rms so I used the 55 watts on the table. That said to tune to 14.8 volts. I tuned the amp to 14.5.... with 1khz

However, the amp gets very hot and shuts off. (alpine f450)
How do I go about diagnosing it?
Do I have a faulty amp, and that is what is screwing my tuning up. Or am I just retared? My coaxles that are in the back are much louder than the comps and they run off the HU.

Values for Common Speakers:
5 Watts -- 4 Ohms, V=4.47 -- 6 Ohms, V=5.47 -- 8 Ohms, V=6.32
10 Watts -- 4 Ohms, V=6.32 -- 6 Ohms, V=7.74 -- 8 Ohms, V=8.94
15 Watts -- 4 Ohms, V=7.74 -- 6 Ohms, V=9.48 -- 8 Ohms, V=10.95
20 Watts -- 4 Ohms, V=8.94 -- 6 Ohms, V=10.95 -- 8 Ohms, V=12.64
25 Watts -- 4 Ohms, V=10.0 -- 6 Ohms, V=12.24 -- 8 Ohms, V=14.14
30 Watts -- 4 Ohms, V=10.95 -- 6 Ohms, V=13.41 -- 8 Ohms, V=15.49
35 Watts -- 4 Ohms, V=11.83 -- 6 Ohms, V=14.49 -- 8 Ohms, V=16.73
40 Watts -- 4 Ohms, V=12.64 -- 6 Ohms, V=15.49 -- 8 Ohms, V=17.88
45 Watts -- 4 Ohms, V=13.41 -- 6 Ohms, V=16.43 -- 8 Ohms, V=18.97
50 Watts -- 4 Ohms, V=14.14 -- 6 Ohms, V=17.32 -- 8 Ohms, V=20.0
55 Watts -- 4 Ohms, V=14.83 -- 6 Ohms, V=18.16 -- 8 Ohms, V=20.97
60 Watts -- 4 Ohms, V=15.49 -- 6 Ohms, V=18.97 -- 8 Ohms, V=21.90
65 Watts -- 4 Ohms, V=16.12 -- 6 Ohms, V=19.74 -- 8 Ohms, V=22.80
70 Watts -- 4 Ohms, V=16.73 -- 6 Ohms, V=20.49 -- 8 Ohms, V=23.66

thanks Phil

Where did you get your info on tunning the amp gains?

Are you using a oscope to tune it? If you are using a multimeter you will never find out where it's clipping which can cause some amps to go into protection.

What cd are you using to get the 1k tone?

What is the sensitivity on the speakers?

 

[garyk1970]

amp

if amp gets hot and cuts off you either have too much of a load,or voltage is dropping.amp is going into protection mode and saving itself.

see what the most load per channel the amp can handle and dont go any lower.

grab a volt meter and make sure voltage doesnt drop at amp .02 volts lower than what voltage shows at battery while playing amp.

your gain control is to match the amps output volume (how fast it turns up)to the pre amp voltage of the radio.not to the speakers.

heres how to set the gain control on amp;
play a song on a cd that you are familar with.turn amp all the way down,and turn radio all the way up and then back down a few clicks on the volume control to stop the clipping all radios have at full volume.then slowly turn gains up on amp untill you start to hear distortion/clipping,then turn gain back down untill the(clipping)is gone.i usually turn rear up alittle more since they are bigger speakers and father away.

hope this helps, Gary.

if you dont understand this,seek professional help,a good stereo shop is willing to help teach you,not just to take your money.

 

[SGRIM]

A general rule of thumb I have always used is a little over half way. Then I crank it up to a fimilar tune and make sure no clipping or distortion. I don't compete so I tune for my likening

 

[Madcat455]

How are your speakers wired?? Are you running stereo or Mono.

If mono, how did you bridge the speaker wires (parallel or series)?

Amps usually get too hot when you're running the impedance lower than what they're rated for. Either the low impedance or extra heat from running low impendance will trigger the protection.

Clipping and low voltage will do it to, but I have yet to actually see it happen.

My Comp car would actually drain the electrical system soo much that all the lights would completley shut off with the cycles of the amp...lol. Amp never went into protection from the voltage drop.

 

[Madcat455]

A general rule of thumb I have always used is a little over half way. Then I crank it up to a fimilar tune and make sure no clipping or distortion. I don't compete so I tune for my likening

That's how I did it too... I used what I call the ¾ rule. Stereo at ¾ volume... then tune the gain until it distorted.. and backed it down. Although, I NEVER went over ¾ gain on the amp either... if I needed more, I bought a bigger amp

Distortion is to stereo systems, what Spark knock is to turbo engines

 

[ledzeppac]

Where did you get your info on tunning the amp gains?

Are you using a oscope to tune it? If you are using a multimeter you will never find out where it's clipping which can cause some amps to go into protection.

What cd are you using to get the 1k tone?

What is the sensitivity on the speakers?

Its common knowledge, but I also checked here: Amplifier Setting Tutorial - Car Audio Forum - CarAudio.com

I tired to tune by ear but the speaker were not distorting(audable), BUT the crossovers were glowing extremely bright and the amp would get extremely hot and go into protection mode. So bright that it turned night into day in the car.
Again this is with no distortion. So then I tried the volt meter way and that set the gain to 1/4 way up, not loud at all. I know its not supposed to be earthshaking, but from what I understand all you need is 30 watts to components and your ears will start to ring.... AND still amp in protection mode.

I downloaded 1khz and 50 hz tones onto my ipod. I assume they are in 0db...

So, tuning with a volt meter is worthless?
I'm going to re-ground the amps. My mono amp is on same ground with no overheating problems.
I'll try to check volt droppage

4 ohm comp speakers= 4 ohm per channel 4 channel
14 gauge wire used
4/5 gauge power to distribution block then 8 or 9 to amps


Does this sound like retard user error, or faulty amp?

 

[garyk1970]

did you test speakers leads at amp to ensure the amp load is 4ohm?if so,then sounds like the amp power supply is going south(an internet guess).

speaker output on an amp is a/c.distortion is d/c.there is usually lamps in a passive x-over to "burn" the d/c.check the ohms and do a voltage drop.

 

[Madcat455]

I can see a voltage drop causing a protection fault, but not heat. If you're getting that kind of heat, then there is definatley issues somewhere.

Take your vot meter and check how much the amp is using (power wire).

There's a formula to convert volts to watts, but I forget it... gonna check.

I would also use your OHM meeter and double check the speaker wires at the amp to make sure the speakers are indeed 4 ohm. Just to be sure a wire isn't grounded somewhere.


A bad ground will cause excessive heat (of the ground wire), and poor performance of the amp, I melted one of my ground wires once..lol.

but glowing crossovers is a problem. When it was glowing, did you take a voltage reading at the speaker terminals??

 

[garyk1970]

there are three protection modes for all name brand amps; thermal,low voltage,output overload.

alpines are the worst about going into protection mode with low voltage.thats my guess, that there a short somewhere in the wiring or speaker terinals touching ground.wiring pasive x-overs takes alot of concentration even for someone like me who has installed them for twenty years.

there isnt and voltmeter that im aware of that can measure the amount of amps an amp can draw.

if speaker leads at amp shows four ohm,and voltage is good,my guess is still the amp.

 

[TURBOV6]

So, tuning with a volt meter is worthless?
I'm going to re-ground the amps. My mono amp is on same ground with no overheating problems.
I'll try to check volt droppage
?

I use a hand held ocilloscope. Tunning you amps by ear for clipping can damage your speakers.

Check your ground connection first. You can also meter the ground and check if you got min resistance. Where is your ground point?

 

[$1987 GN$]

well I'm making this harder than it is...

I printed off a table that is used to set gains on my amp. Alpine f450 70x4

I have kicker comps that are rated at 60 watts rms so I used the 55 watts on the table. That said to tune to 14.8 volts. I tuned the amp to 14.5.... with 1khz

However, the amp gets very hot and shuts off. (alpine f450)
How do I go about diagnosing it?
Do I have a faulty amp, and that is what is screwing my tuning up. Or am I just retared? My coaxles that are in the back are much louder than the comps and they run off the HU.

thanks Phil

I hate to tell you that you can not use 1 k alignment tone to try and adjust that amp with those speakers.

IIRC that amp is a sub amp and is not made to pass that freq so you are driving that amp way past it's abilities.

IIRC it passes up to ~ 200 hz so trying to put 1k through it and tune it will not work.

Use 100 hz

Later AJ

 

[8UWITH6]

I use a multi-meter on my old school Rockford Amps. I have never ever burned one down or had one shut off, and I run them as low as 1.34 ohms mono (bridged).

Ill try to find the chart I use to set my gains.................I have always used a 50hz tone recorded at 0db for sub amps.......

 

[TURBOV6]

Also before you tune any amp you need to check clipping at the hu.

 

[ledzeppac]

ok, why is it that these cars make me stupid?

HU is set 32/40

Well I attempted to get things straight this afternoon. I moved the grounds to two seperate locations. There is a bolt opening near the package shelf that everyone uses to bolt their rear seat breaces on. I used both of those (one for each amp). Yes, I scrapped down to bare metal.

Then I checked voltage at the amp. Scanmaster showed 11.8 and amp power wire showed 11.8 DCV

Then I tried to check for ohms. I was getting all kinds of readings. Everything from -134 all the way to 9.9. Yah I dont know... I used the mushroom shaped thingy on my Fluke multimeter

So I connected the speaker wire to another set of coaxles I had laying around and those read 5.7-11.6 ohms on each. The speaker that was NOT playing showed a consistant 7.7ish

Am I doing something wrong to check ohms?

Crossover still glowing "white." Volts at the crossover was max 6.4... Does that mean that the amp is producing to much distortion?

sure enough the amp got as hot as GN paint in 100 degree weather and shut off.

What the hell can I be doing wrong? I need my music back!

Thank you very very much

 

[TURBOV6]

HU is set 32/40

What is the brand of the deck?

What volume is the deck clipping at? Well you can't really tell if you don't have a oscope. If you got a mini amplified speaker you can actually hear it clip.

I moved the grounds to two seperate locations. There is a bolt opening near the package shelf that everyone uses to bolt their rear seat breaces on. I used both of those (one for each amp). Yes, I scrapped down to bare metal.

That is a bad ground. That brace is tack welded to the body. If you seperate the grounds you might run into a ground loop problem and pick up engine noise.

Then I checked voltage at the amp. Scanmaster showed 11.8 and amp power wire showed 11.8 DCV

Don't use the scanmaster to use as a reference on voltage. You will lose about a volt and a half at the scanmaster.

Then I tried to check for ohms. I was getting all kinds of readings. Everything from -134 all the way to 9.9. Yah I dont know... I used the mushroom shaped thingy on my Fluke multimeter

When you check impeadance on the ground you need to go directly at the battery ground. A good ground will be around 2-4 ohms from the battery. Also it a good idea to redo the ground connection to the battery to the body (you will notice a small 10g wire going to the body). Used a bigger gauge wire.

So I connected the speaker wire to another set of coaxles I had laying around and those read 5.7-11.6 ohms on each. The speaker that was NOT playing showed a consistant 7.7ish

If it's reading 5.7-11.6 ohms it might be a bad voice coil. If you are checking impeadance on the speaker make sure it's disconnected from the amplifier.

sure enough the amp got as hot as GN paint in 100 degree weather and shut off.

If the amp is getting hot and shutting of then it's going into thermo protection that mean that you speaker load is too low. How many drivers are you using on each channel?

 

[garyk1970]

disconnect the speaker leads at amp BEFORE you take the ohm measurements ,then let us know what the ohms reading are for each channel.

 

[ledzeppac]

What is the brand of the deck?

What volume is the deck clipping at? Well you can't really tell if you don't have a oscope. If you got a mini amplified speaker you can actually hear it clip.



That is a bad ground. That brace is tack welded to the body. If you seperate the grounds you might run into a ground loop problem and pick up engine noise.


Don't use the scanmaster to use as a reference on voltage. You will lose about a volt and a half at the scanmaster.



When you check impeadance on the ground you need to go directly at the battery ground. A good ground will be around 2-4 ohms from the battery. Also it a good idea to redo the ground connection to the battery to the body (you will notice a small 10g wire going to the body). Used a bigger gauge wire.


If it's reading 5.7-11.6 ohms it might be a bad voice coil. If you are checking impeadance on the speaker make sure it's disconnected from the amplifier.


If the amp is getting hot and shutting of then it's going into thermo protection that mean that you speaker load is too low. How many drivers are you using on each channel?

Panasonic I got from a friend. Turns out the HU is an Inian or Arabian model... Panasonic cq-c730(I think)
Where should I ground amps?

I've found that the scanmaster volts have been pretty accurate in the past on mycar. And the voltmeter proved it showing 11.8 also. But in the future I will double check at battery. Oh oops. I figured I would wanted to check why there is a load...

No power and ohms at crossovers showed 3.4-3.5, and the amp terminals showed a 3.6 and a 3.7.
As a reference my JL coaxles showed 3.3 on both.

1 speaker per channel. I'm only using channels 1 and 2 with no 3 and 4 as of now.

So, ohms are good? There is no volt drop. Internal amp problem?

thank you

 

[garyk1970]

you would like to see 4 ohm or more(higher) at each speaker lead at amp,but highs are not as much as a load as bass,so it should be ok.

leaving some output channels unused,ive seen some wierd stuff,i dont think thats the case here.

since youre only using two chanels,try this. hook up one set of componets at a time to see if one set plays without getting amp hot.(this test will see if load changes as speakers play;ie internal short in speaker)

then try to see if you use channels 3 and 4 if amp does better.(1 and 2 bad channels?)

OH YEAH,look real close on alpines' adjustment side of amp and make sure you dont have the input switch set to L+R or L mono .should be on a "stereo in" setting.check the unused channel inputs too.these settings are only for bridging a subwoofer.

keep us posted

 

[Madcat455]

What kind of speaker wire are you using?? Regular 2pair, Monster cable, etc.

If regular, what gauge (I missed it if you've already mentioned it).

Just as a quick check, take off the speaker wires from the amp... Place one lead from the meter on a wire, and the other on where the amp grounds... see if you get a ohm's reading at all. Check each set of speakers that way.

ANY reading except *infinity* and you've got a wire shorted. A shorted wire will cause all the heat problems you've been having.

ALSO.... Since you've mentioned that the crossovers on the speakers are "Glowing", I'm assuming that they are F'd now. I can't imagine them taking that kind of heat and retaining any sort of functionality.