Lets talk voltage please

[>>SQL<< 10+ year member]

This is my first time running high power non-regulated amps.

In the past I always ran JL Audio Slash amps and before that I only ran a few hundred watts (think back in the day)

So I just hooked up my first high power (non-regulated) system last night.

I have a volt meter installed in the car.

If I keep the gain at less than 1/2 way on the Sub Amp (Fosgate T10001BD) the voltage stays above 13 (12.5 on long hard bass lines)

What voltage do I need to stay above in order to be safe?

I have the Big 3 done, I have an HO Alt but have not installed it yet.

Also I know we talk about how capacitors do very little but about larger ones?

I have a 15 fared AlumaPro sitting in my closet, would one of that size be helpful?

What voltage is safe to drop to before I need to grab the volume and turn it down?

Plus it is not easy driving and watching a volt meter.

thank you

Click to read more...

 

[ahole-ic]

Set your gain with dmm. 1/2 way means nothing. You're probably clipping it hard and that's why your voltage is dropping.

Big caps have big ESR making them more worthless than the smaller electrolytic caps. Put the HO alt in. Seriously, set your gain properly. I guarantee if you're talking about "my gain is only halfway" you didn't set it properly and you are clipping like a gay hairdresser.

 

[>>SQL<< 10+ year member]

I am not clipping like a gay hairdresser.

I finished the system up last night after dark.

My GF had to take the car to work today at 6am.

I put the gain where it could be played loud with little voltage drop.

It was not set with any other method but making sure my GF could drive the car to work the next 2 days without worrying about the system.

I know how to set with a DMM and will do that Sunday when I get the car back.

My question on this thread is what is an acceptable voltage level? 12.5? 12.0?

At what voltage does is it become potentially dangerous? 11?

 

[ahole-ic]

I am not clipping like a gay hairdresser.
I finished the system up last night after dark.

My GF had to take the car to work today at 6am.

I put the gain where it could be played loud with little voltage drop.

It was not set with any other method but making sure my GF could drive the car to work the next 2 days without worrying about the system.

I know how to set with a DMM and will do that Sunday when I get the car back.

My question on this thread is what is an acceptable voltage level? 12.5? 12.0?

At what voltage does is it become potentially dangerous? 11?

It's different for every amp but I will tell you this, when the voltage is dropping, you cannot just set it to drop to 12v. While driving down the road not paying attention it will drop to 12v, then it will drop lower and lower and lower. I personally wouldn't run an amp below 12.6. It's hard on your alt, batts, and amp. I keep mine above 13v unless I'm burping.

 

[sacsking916 5,000+ posts]

As ecrack said 12.6 is the bare minimum. The 12v ratings from most companies is at 12.8. I.try to never drop below 13. Instal that H/O alt first off

 

[THATpurpleKUSH 5,000+ posts]

From the sounds of your gain setting you are clipping it hard. Just because you cant heard audible distortion doesnt mean you are not clipping. Only way to find out is with an oscope.

 

[>>SQL<< 10+ year member]

From the sounds of your gain setting you are clipping it hard. Just because you cant heard audible distortion doesnt mean you are not clipping. Only way to find out is with an oscope.

How can you tell from the sounds of my gain setting that I am clipping it hard?

Please explain that to me.

 

[ahole-ic]

How can you tell from the sounds of my gain setting that I am clipping it hard?
Please explain that to me.

Because 1/2 gain is usually matching to less than a volt. Most head units today put out 4v at their maximum output and 2v at half.

 

[THATpurpleKUSH 5,000+ posts]

How can you tell from the sounds of my gain setting that I am clipping it hard?
Please explain that to me.

This

Because 1/2 gain is usually matching to less than a volt. Most head units today put out 4v at their maximum output and 2v at half.

 

[>>SQL<< 10+ year member]

Not that I am auguring but this is from the manual for my amp

ADJUSTING GAIN

To adjust the gain setting, turn the amplifier gains all the way down (counter-clockwise).Turn the source unit

volume up until distortion is audible and then turn it down a bit until the distortion is inaudible.This will be

about all the way up on most source units. Next, increase the amplifier gain setting until adequate volume is

achieved. Rockford Fosgate source units do not distort, so the volume can be used at maximum setting.

NOTE:Best signal to noise and dynamic range are realized with the gain at minimum. Most users find

adequate gain and volume is achieved at about halfway in the adjustment rang

 

[agarabaghi 10+ year member]

you clearly don't know how to tune with a dmm, or you wouldn't be having this conversation. Tune it with a DMM and come back to us. My gains are setup a little less than 1/4 up and I achiever the 36v the math told me i should be getting for my setup... and since you dont know the math here it is ...

sqrt(wattsrms + ohm of speaker)

 

[ahole-ic]

Not that I am auguring but this is from the manual for my amp


ADJUSTING GAIN

To adjust the gain setting, turn the amplifier gains all the way down (counter-clockwise).Turn the source unit

volume up until distortion is audible and then turn it down a bit until the distortion is inaudible.This will be

about all the way up on most source units. Next, increase the amplifier gain setting until adequate volume is

achieved. Rockford Fosgate source units do not distort, so the volume can be used at maximum setting.

NOTE:Best signal to noise and dynamic range are realized with the gain at minimum. Most users find

adequate gain and volume is achieved at about halfway in the adjustment rang

Assuming that were true, why would there be a gain knob at all? since every head unit can be matched to every amp just by turning it up halfway why is there any need for a adjustment?

 

[agarabaghi 10+ year member]

That may have came off harsh, plus your a good guy since the amp you sold me was as described and cheap. But seriously, just tune it with a DMM, and once you install your ho alt you prob wont notice dropping in VOltage.

Most alts dont put out full amperage until they are reving a bit... so take a look at how your volt meter acts while reving the engine and see if it drops as quick ...

 

[>>SQL<< 10+ year member]

Actually I do know how to set gains with a DMM.

Like I wrote before I finished installing this system after dark last night outside in about 30 degree weather.

My GF took the car this morning at around 6 am.

I was just pointing out that the User Manual for this amp recommends to put the gain up 1/2 way.

I thought that was funny.

When I get some more time with the car, which will be this Sunday, I will set with the DMM.

Now I did drop out of the 9th grade but let me see if I can solve for x

1,000 (you have plus however I think times would make more sense) 1 ohm = 1,000

take the square root of that which is about 31 volts ac

This whole thread was about acceptable voltage drop but seems keep being turned into how my gains are set.

Again I will not even be able to drive in this car until Sunday and when i was demoing the system to my GF last night she was holding her hands over her ears so I do not think I have to worry about clipping or voltage drop while she has the car these next few days.

I just wanted to know what voltage I should make sure I stay above, not how to set my gains or comparing my amp to a gay hair cutter.

I think I got the answer, it is 13 volts.

 

[agarabaghi 10+ year member]

well technically, no voltage drop is acceptable. I dont let the voltage on the boat go under 13v... usually its around 14.4