UncleTony

xls 1000 Voltage Gain?

9 posts in this topic

Hello UncleTony,

Crown doesn't publish it's voltage gain specs because they use different philosophy for building bigger rigs. what comes out of that is the voltage gain is different on every amp. well, except for the itechs which you set it to whatever value you want. The good thing is we can calculate it ourselvs.

Usually people asking for data on the voltage gain for this or that amp are trying to mix amps from different manufacturers in one rig and if that's what you're trying to do, let me know because it doesn't really matter.

So, let's get our calculators...

An amp with a voltage gain of X40 will output 40 times it's input sensitivity spec to reach full power on the output, on the XLS series the input sensitivity is 1.4V.

That means that if we put 1.4V on the amps input we get at 8 ohm for the XLS 1000 215W per channel. So we'll calculate the maximum output voltage:

V out max = SQR(P max X R) = SQR(215 X 8) = SQR(1720) = 41.473V

The amps voltage gain is the ratio vetween the input sensitivity and the amps maximum output voltage. So we take the two figures (Voltage sensitivity=1.4V and Maximum output voltage=41.473V) and find the ratio between them, that's:

R = V1 / V2 = 41.473 / 1.4 = 29.625

Let's redo it for 4 ohm load:

V out max = SQR(P max X R)=SQR(350 X 4) = SQR(1400) = 37.417V

R = V1 / V2 = 37.417 / 1.4 = 26.726

That's it

Avi

Share this post


Link to post
Share on other sites

Except that the actual gain don't change with the load! How could it change, the amp doesn't know the load.

The input sensitivity spec is stated for 4 ohms, so the gain you calculated for 4 ohms is correct but will be the same for 8 ohms. A perfect amp would double it's power at 4 ohms. Since we're in the real world it won't happen. What will happen is that the amp will clip sooner at 4 ohms than 8 ohms. So the amp will need a tad more signal on the input to give it's full 8 ohms power. I'm too lazy to calculate right now! :)

Share this post


Link to post
Share on other sites

Dear Deromax,

Thank you for further clarifying the subject :)

I calculated the input sensitivity for 8 ohm load:

R = V1 / V2 => V2 = V1 / R = 41.473 / 26.726 = 1.55V

Avi

Share this post


Link to post
Share on other sites

1.55V looks just about right! :)

This is actually a not well known concept and I had to devise it myself since it's rarely discussed or stated in amps specs. Commercial amps (like the CTs) seems to give both input voltage spec more often.

Share this post


Link to post
Share on other sites

Hey Guys .

Been a while but I have a question. If I have a xls1000 in bridged mode with a 4 ohm load what voltage do I need to get full output of the amp?

Thanks for any help in advance.

Share this post


Link to post
Share on other sites

1.4V! :)

Don't forget : 1.4V gets you full voltage out!

As per dakos : input sensitivity is 1.4V (see above)

Alain

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now