Review: Crown new DriveCore XLS 1000 Class D Pro Amp - Page 2

I might agree with a blanket "not necessarily" if the pre output impedance is unusually high and the amp input impedance is unusually low, and these two are mated.

However, the way I read your post it seems to imply something more specific than that. And, I'm not familiar with the cases of clipping at or below the rated pre out level you seem to mention. Do you have any links or anything to these (I presume) tests/measurements?

I need to correct what I said. I can't hear the fan at all. Last night when I got the amp, I sort of rushed through a quick eval. I had not noticed that the PS3 was on! And it's got a pretty loud fan.

So, with no sound on, the fan on the XLS 1000 is quiet or off...I can't hear it at all.

Something I have not run into...I am getting a hum in my surrounds from the XLS 1000. Going to take time to figure this one out.

It does have a ground plug, unlike my RX-Z7 and my XPA-3, so I guess it's getting a ground loop. It's not that bad, but I will have to pull it out of my setup if I can't fix it.

I've had other set ups were there was a very low level hum or just low level noise floor . The cure could be as easy as putting a 50K resistor inline between amp and pre amp, more or less may be needed.

Thanks for the idea.

This works best if the noise / hum does not change with the volume.

I believe I isolated the hum to the cable input. I could probably get an isolation transformer.

However, there's a hiss which I can hear from my listening position which is independent of amplifier gain and does not go away when the interconnects are disconnected.

That surprises me. If it's not a defect in the amp, the amp has a pretty high noise level.

The XLS 1000 unit I have is quiet, no hum or hiss. The fan is very very low noise too, 99% of the time it can't be heard. I use it to power a sub, but I did listen to it with full range speakers, its a good amp for the money. As you say, you have hiss with the interconnects disconnected, so the amp is hissing well thats just about hopeless. The only fix is to add resistance to the tweeters and than compensate for the loss with tone/eq boost. Auto set up systems may also flatten the high end roll off. The easy way is to put some resistance in the speaker line to see how much is needed to cover up the hiss and hear if it can be done with less than 100 ohms. Use 10 watt rated and this is only for testing not high levels for long times.Than use that resistor for only the tweeter. I had a sony avr with hissing rears in most sound modes, I returned than unit in a week.

Yeah, seems possible it has a defect then...kind of a bummer. I would not have expected Sweetwater to sell me a demo with issues, and they have been reliable in the past.

I guess I may have to call them up, and discuss it.

Lol, I know plenty of people that would disagree just because it's a pro amp (even though they haven't heard it). You would also get hammered for owning Emotiva.

You just don't visit the right boards

I have been thinking about this hiss issue again. If I can't return it, or don't want to deal with returning it, I could move it to the rear surround channels. It might be quiet enough back there that I can't hear it

Guys, this is lengthy but worthy read regarding a pro equipment in a consumer rig.

http://www.hometheatershack.com/foru...ur-system.html

Did you try the resistor fix ?

This mod and use of the phone input is for driving sub woofers only
I'm sure most of you old timers have a 2ch pre amp getting dusty. I'm using a HK 725 which was sota in its day. The phone input uses the RIAA equalization which is a great boost for a sub. You will need to put a 1meg in line so not to overload the this very high gain input, I recommend only to install the 1meg resistor inside the pre amp's metal caseing as shielding is of the highest importance. At frist, just test it out at low levels to hear if there is any input overload. This will clean up any muddy sounding subs. Please take into account that demands on the sub will be higher than before, not for wimpy sub drivers and underpower amps. Once you try it, you'll love it.

Yea, I know that there is a roll-off starting at around 20hz, but that shouldn't be a problem for most, it will help to lessen the demand on the hardware.

I called up Sweetwater yesterday, and they offered to replace the demo amp I bought with a brand new unit and they will pay shipping. They are a very customer oriented company. Given that someone else in this thread said their 1000 was quiet, I am assuming the replacement has a high chance of not having the hiss issue.

That's good to hear. Nice customer service.

I'm using the XLS 1000 bridged for sub use, lowpass set for THX use, 79/83 switching between the two setting to hear which sounds best. At no time is the fan and hiss/hum a problem, if I could ask for more it would be to be able to dim or turn off the blue lighting and all be in a 17" wide package (remove the mounting wings), 19" makes it seem its bigger than it has to be. The low current draw is a big plus.

When I get the new amp in, I will post the results. I will still have hum without the cheater plug I would guess, but the hiss should be gone, I hope

Hiss/hum could be from your pre amp. Are you planning on using this amp for sub or full range. I should point out the input sensitivity of this amp is low, I needed to use a pre amp (HK 725) to boost the gain of the sub output of my onkyo 3007. I'm now using the AUX input at this time, the modded phono input which also works and sounds good, but over time with listening and tweaking the aux sounds better balanced, the phone EQ was very impressive at first, but over time it was just to much boost for most source material, as most things would walk off the shelf and the pipes and wires would rattle behind the walls.
.

It's not from the pre-amp. It occurs when there's no source connected and under all gain settings.

I am using it full range to power surround speakers.

My Z7 should have plenty of drive for my purposes. I have no simple way to test it. I believe the suggested method (without scope,) is to attenuate the output from the Z7 and play a test tone, and listen for the test tone to change character while measuring with an RMS meter (and I imagine applying some math to work out the pre out voltage given the input impedance and attenuator resistance.)

I suppose I could manage that. If my amps input imp. was 40k, 40k of resistance should drop the drive voltage in half. Not sure that's good enough to protect my sanity/hearing with a 1khz test tone or not.

If you run the Z7 auto set up and checks out all in range you should be good to go. If not and there is a problem, then you have to take it to the next level.

any update on your Crown XLS amp?? Still a hiss or hum or has the new one recified the problem. Just inquiring since I'm in the market for a good bang for the buck amp for sub use.

The replacement had less noise. But it does have some noise. It's hooked up to some Klipsch books. Can't recall exact model. I would say there's audible hiss to at least 8". I can't hear them where I sit at all.

I am planning to use Crown xls1000 with my VMPS sub. I will have Paradigm X30 active crossover unit controlling the phase, crossover & gain. With this setup where do I set the gain controls on the Crown amp so that I can use the gain control only on the Paradigm X30 unit?

Is there a way to dim the display on the Crown amp?

Black electrical tape.

I've got a little different issue on the Crowns.
First I run a 9.1, 7 channels are all powered by individual Crown XLS 1000 amps. The front high channels are stereo split on a single Crown XLS 1000. Sub is a Paradigm Sub 1.
Fronts are Axiom M80 v3
Center is Axiom VP180
Highs are Axiom M3
Surrounds and back are QS8

I have been VERY happy with the sound, I do have a low level ground hum, but that's somewhere in a ground loop unrelated to the Crowns.

They plug into a Panamax M5300 for power conditioning.

The problem is I can automate on my all the equipment except the Crowns. I was trying to find a way to have them shutdown through the power source but I cannot find a way to do that.

Any suggestions?

You have a rack of amps plugged into a power conditioner? Sure it's rated for for all those amps?

Hummm max 1500 watts.........all outlet combined