Need help with my Crown Xti2000

[clayh]

I’ve got a bit of a problem….

I have a 4 speaker IB currently powered by a Nady XA-900, the system works well but it is a little under powered. I upgraded the amp to a Crown Xti 2000 and configured the amp’s DSP for bridged mono subs. Here’s the problem with only the sub connected (no input) the sub hums as soon as the amp is turned on no matter what the gain is set for. I talked to Crown’s tech support and they told me it was my sub and they couldn’t help me, I went on to the Crown online forum and the moderator told me to send in the amp for repairs. I sent in the amp for repairs and the Crown tech call me and said there was nothing wrong with the amp and he was sending it back to me.

I’m at a bit of a loss as to what I should do next, any ideas would be appreciated.


The facts:

- 4 x 18's wired in a series parallel fashion to create a 4 ohm load.
- The sub is about 10’ from the amp and is feed with 10 gauge wire.
- When connected to a Nady XA-900 there is no hum.
- I wired a dedicated circuit for the amp, and have even tried connecting it to a very large UPS.
- My input device is a HK AVR745, but for testing I have not bothered to hook it up because of the hum.
- I have tried the amp on a different sub setup and the hum is not as noticeable, but the sub out of that receiver did not seem to have enough gain for the amp’s input.

[ThomasW]

Might check to make sure the AC outlet is properly wired.

Change the amp settings to stereo, see if that helps.

If there's any DC on the AC line that can cause problems. So you might try some DC blocking caps on the AC line itself.

Beyond that I don't know, I've seem more issues and complaints regarding those amps than any other made by Crown

[txsmoke]

A bad cable from the processor might cause this. If the amp in bridged mode is only using one of RCAs for input (assuming you were running 2 before) and the one you are using now has a bad ground, stereo mode may have been fine, but in mono, the 'good' cable may not be used. Try switching the RCAs and see if that helps. Also, try switching the input on the amp, if possible.

I don't know what Crown was thinking when they told you it was the speakers. Speakers only reproduce what is given them. They themselves can't inherently 'hum'. Maybe they were confused and thought you had blown a speaker and was hearing the tell-tale scrape/scratch.

Mike

[aaks38]

Clayh, im actually contemplating getting the same amp. I was curious how you like it and how flexible is it in terms of using the Parametric eq and filters?

A few things you may want to try are to make sure all AC plugs are grounded at the same potential or same junction box.

Another thing you can try is to reduce the gain on the amp and increase your LFE output from your receiver.

[rickf325]

Dec 18, 2007 22:52:16 GMT -7 aaks38 said:

Clayh, im actually contemplating getting the same amp. I was curious how you like it and how flexible is it in terms of using the Parametric eq and filters?

A few things you may want to try are to make sure all AC plugs are grounded at the same potential or same junction box.

Another thing you can try is to reduce the gain on the amp and increase your LFE output from your receiver.

I have a Crown XTi-1000. The gain on my receiver is +12dB , through an LLS, then to the Crown. No hum whatsoever. Note that the receiver and amp are both plugged into the same AC circuit.

Re: parametric EQ and filters: It is easy and super configurable. But, you have to use a computer hooked up via an A-B USB cable to access those functions. And the program is Windows based, so it is a little more complicated if you are a Mac guy (like me).

[idunno]

I have an XTi 4000. I've tried using it in bridge mono and experienced the same type hum you describe. I'm afraid that hum is a part and parcel of the XTi design and there's nothing you can do about it. It sure isn't an acceptable level of hum for home theater users but may be acceptable for the Pros.
I use one channel of my XTi in stereo mode which is supposed to be 1200 watts @ 4 ohms. There is NO noticeable hum in that configuration. That is MORE than enough power for my 4600 cubic foot listening room and 1 LMS 5400 18" in a 6.8 cu. ft. sealed box. I suspect that 1200 watts is an inflated number but whatever the real power rating is, it's more than I need or use.
My choice of the Crown XTi 4000 had more to do with the DSP than the power rating. The System Architect software is the really neat part of the amp.

[ironhead]

Have you tried without cable TV hooked up? I had a problem with hum that originated with my cable hookup.