Gain Settings on Xenon Amps

maka78 · Post by **maka78** » Thu Oct 09, 2008 5:32 am

So I'm so confused now... I usually set my gains with the DMM by doing the calculation and was off doing that last night with two X200.4s.

I wanted to run each x200.4 bridged so I get 400x2 @ 4 ohms. Doing the calculations, I'm expecting 40V from the bridged outputs. My HU goes all the way up to 80, so I usually set that at 70, flatten out all the EQs, and start raising the gains on my amp till I hit my number.

This works fine on the TIs I've done it to, but with the xenon, it never hits 40, even when the gain is set all the way clockwise! I had to set my HU to 78/80 in order to get the 40V.

Is there something I should be factoring in with the Xenon amps when I set my gain? With other amps I've used, all I do is set the gain for 4 ohms, and I can use it for any other configuration...

For example, on my TI400.2, I will set the gain to 100@4 ohms for 100x2 operation. I look for 20V. If I want to run 200@2 ohms for 200x2 operation, I don't have to change the gain. If I want to run 400x1 @ 4 ohms, again, I don't have to change the gain because the output on the bridged terminals give me 40V when it's 20V stereo.

From the Xenons having the XeLoad, I'm guessing I have to change the gain every time I change the setup, is this correct?

Capital_M · Post by **Capital_M** » Thu Oct 09, 2008 5:39 am

Xenons like a high input voltage, I use a linedriver with mine

Capital_M · Post by **Capital_M** » Thu Oct 09, 2008 5:41 am

Also with the xenons you always do the calculations at 4ohms, even if your final load is 1 ohm

maka78 · Post by **maka78** » Thu Oct 09, 2008 6:37 am

Capital_M wrote:Xenons like a high input voltage, I use a linedriver with mine

I'm waiting for my line driver to come in, but that's gonna be some time. Until then, I'm only getting 200 mV from the HU. I guess I have to wait then. Would I be clipping my signal if I'm turning the HU up to 78/80 and having the gains all the way up on the amps? If so, should I lower the HU to 70/80 or lower the gains a bit or both?

Capital_M wrote:Also with the xenons you always do the calculations at 4ohms, even if your final load is 1 ohm

So, If I'm doing 400x2 @ 4 Ohms, that's supposed to show 40V at the bridged terminals. If I do 200x4 @ 4 Ohms, that should show 28.28V at the stereo terminals. Even though I'm not 100% sure right now, I don't think the gain is the same for them. Which calculation should I stick with? I'm guessing, from my understanding, I set the gain at 28.28V at stereo and do not touch the gain any more (which is what I would do with the other amps), no matter what the reading is for bridged or different setups, is this right?

Capital_M · Post by **Capital_M** » Thu Oct 09, 2008 6:59 am

Ok, I dont have expirence with briding xenon amps, so maybe someone else can chime in

Post by **stipud** » Thu Oct 09, 2008 7:19 am

The amp does 400x2 at 8 ohms, so for bridged you would have to do an 8 ohm calculation, for the same reason you would need to do a 4 ohm calculation in stereo. Just set the gains in stereo, and it won't matter if it is bridged or not.

Post by **fuzzysnuggleduck** » Thu Oct 09, 2008 7:21 am

maka78 wrote:Until then, I'm only getting 200 mV from the HU.

Is that with the HU turned up to 78/80? If so, you NEED a line driver.

maka78 · Post by **maka78** » Thu Oct 09, 2008 8:06 am

fuzzysnuggleduck wrote:
maka78 wrote:Until then, I'm only getting 200 mV from the HU.
Is that with the HU turned up to 78/80? If so, you NEED a line driver.

I ordered the TLD66 already, but it's taking some time to get to me (for some reason, all electronics are out on the west coast, and I'm on the east).

It's rated at 200mV but it was up to 287mV when it was at 70/80... haven't checked 78/80.

longboard · Post by **longboard** » Thu Oct 09, 2008 8:45 am

these amps love 8-10v so you need a line driver