Loaded vs. Unloaded

[gckless]

I don't know why I'm guessing. Just gonna test it when I get my sub. But if anyone has done it or knows what happens I'm all ears.

[bbeljefe]

The difference is voltage. Your preamplifier is still an amplifier and because of that, it will produce a stronger signal when system voltage is higher. When you set gains with a load on the amp, your preamp signal will be slightly lower because your system voltage is slightly lower.

But if you're not chasing numbers, it's pointlessly pedantic to worry about.

[gckless]

The difference is voltage. Your preamplifier is still an amplifier and because of that, it will produce a stronger signal when system voltage is higher. When you set gains with a load on the amp, your preamp signal will be slightly lower because your system voltage is slightly lower.

But if you're not chasing numbers, it's pointlessly pedantic to worry about.

My worry is about distortion. If I set to max clean unloaded, will I have distortion when it gets loaded down and voltage sags? You're saying input voltage will go down as well, so then it shouldn't introduce distortion right? Or will I simply get less amplitude on my clean waveform?

[bbeljefe]

My worry is about distortion. If I set to max clean unloaded, will I have distortion when it gets loaded down and voltage sags? You're saying input voltage will go down as well, so then it shouldn't introduce distortion right? Or will I simply get less amplitude on my clean waveform?

You won't have any distortion unless your voltage is dropping so low that the amp cannot accurately reproduce the signal... and in that case nothing you can do with gain setting will help.

[TheMonolith2001]

I have searched the net for many many hours on this subject and there is endless debate over the answer. I have done some experimenting myself as well.

Some say it matters, some say it doesn't, some say it does matter but only to a small degree (someone stated if you use a 0db test tone you end up with between 1 and 2db clipping so who cares?) The only thing that seems consistent is that it probably does depend on the amplifier. There is so much talk with not enough backing it up on the car audio forums. You have to venture to more general audio/audio techie forums.

All variables considered I have concluded that the most accurate way is to just do it with the speaker connected with MULTIPLE tones in the speakers playing range. This way you are accounting for everything. The load, box rise, The impedance differences at different frequencies, etc. Load banks are nice but they are usually a consistent resistance which a speaker is not.

oh and yes, ear plugs.

[Kyblack76]

my god...

lost lost lost...

[OrionStang]

From the manual:

7. Disconnect all speakers connected to the

amplifier. (This has already been calculated into

the equation and provides 1- 3dB more gain

overlap on unregulated power supply amplifiers

and 0dB more gain overlap on regulated power

supply amplifiers).

[Kyblack76]

How much of a difference is there going to be setting gain unloaded vs. with a load on the amp? Will be using an oscope, running a sub wired to .7 ohms, DC 5k, if that makes any difference.

use a dd1, and youll be even MORE acute... if your trying to get cute dude....

For real.

[Kyblack76]

I have searched the net for many many hours on this subject and there is endless debate over the answer. I have done some experimenting myself as well.

Some say it matters, some say it doesn't, some say it does matter but only to a small degree (someone stated if you use a 0db test tone you end up with between 1 and 2db clipping so who cares?) The only thing that seems consistent is that it probably does depend on the amplifier. There is so much talk with not enough backing it up on the car audio forums. You have to venture to more general audio/audio techie forums.

All variables considered I have concluded that the most accurate way is to just do it with the speaker connected with MULTIPLE tones in the speakers playing range. This way you are accounting for everything. The load, box rise, The impedance differences at different frequencies, etc. Load banks are nice but they are usually a consistent resistance which a speaker is not.

oh and yes, ear plugs.

dork.....

[Jessica]

what i want to know, this is directed at cableguy and bbiefe, do amps have regulated power supplies on the pre-amp circuit.

if not that seems like a serious design flaw to me. that cicuit is critical and if its not we dd-1 users have been doing it wrong this whole time.

bear with me here.

if they are unregulated, then when we set gains with car off then run the engine the pre-amp will be producing more voltage to the amp and would lead to clipping. if regulated then setting gain on the amp should be done with the car off and you should attempt to keep voltage above your resting voltage when playing.

also, just because you drop below resting voltage does not mean you automagically start clipping, just means the amp is going to pull more amperage and run hotter.

edit

words are hard, see bold type for correction