[marauder1999]

I own a HK avr525 receiver,,rated in stereo mode at 80wpc.

I wanted more power and muscle so I purchased the crown xls402 amplifier to run out of my pre out jacks of my Hk.

I ran the wire from the pre outs of the reciever to the Crown amplifier in, ran my speaker wire out of my newly acquired Crown amp and turned it up.


Too my surprise it isnt any louder or clearer than when I just ran my speakers out of my 80wpc reciever.

Can this be right? I mean this amplifier is pushing 400wpc compared to the 80wpc and they sound the same?

please,anyone have any thoughts?

I dont want to return it if its a goof on set-up on my part or maybe a receiver problem,,maybe its not bypassing the internal amp in the reciever and not allowing the amp in the crown,,is that possible?


Please,any help would be greatly appreciated.

 

[marauder1999]

i just unhooked the crown amp and put the speakers back on the receiver and walaa,,the thing cranks,,now this is 80wpc,,and the crown is rated at 400wpc. And it is no where near the volume im listening too.

Anyone?

 

[Mark Seaton]

Part of it could easily be a matter of gain... I forget if the XLS amps have a gain switch in the back. Also, what did you do for cables between the two? The problem is that you will have to turn the volume up higher with the Crown as it requires more signal input relative to the output. This is common for pro amplifiers. So while you need to turn up the volume more to get the same level, the Crown should play much louder, much more cleanly than your reciever. Remember there are also gain knobs on the front. When you overdrive the Crown, you will see red (I think) lights flash where it says "clip." You can somewhat compensate for the gain issue by going into your speaker calibration and increasing those 2 channels to give you more signal at the same volume setting. Try about +6dB from where you were before.

 

[marauder1999]

Thanks mark, but the gain knobs were turned up completely and then from their i went to the receiver and turned it up. There is no comparison,,it is quite lower in volume and quite frankly,seems as if ive actually lost alot of power. Any ideas?

 

[bpape]

First of all let's deal in reality. The difference between 80 WPC and 400WPC from a purely matmatical standpoint is approx 7db. You need to double power for a 3db increase - all other things the same.


That said, 7db is not insignificant. Also, the Crown is likely to have better damping factor than the receiver. I suspect you either:


1. Have a defective amplifier

2. have insufficient voltage output from the receiver to properly drive the Crown amp.


Solution:

Borrow a pre-pro from one of your buddies that has output rated high enough to meet the specs of the amp and hook it up to the Crown and the receiver amp section. If the receiver is still significantly outperforming it, you have an issue with the amp. If not, then your receiver is simply incapable of delivering enough current to drive it properly.

 

[DoyleS]

The XLS 402 is a Pro Audio Amplifier and is looking for a Pro line level. It does not have a switch to select Consumer Line Level. Consumer Line level is around 316 mv while the XLS 402 wants to see about 1 volt to drive it to full output with a 4 ohm load. The bottom line is that you are shy about 7 to 10 db of gain to drive that amp to full output with your consumer output Receiver. There are converters (gain blocks) available that will raise the level by the required 10 db to get full output. Not sure what else to tell you. The standards are different and that receiver has a sensitivity that is probably around 200-300 mv for full output whereas that amp needs about 1000 mv for full output.


..Doyle

 

[Greg_R]

When my EQ fried my Crown amp (K2) I was very pleased with Crown customer service. Give them a call if the amplifier is defective (or return to the store).

Quote:

Too my surprise it isnt any louder or clearer than when I just ran my speakers out of my 80wpc receiver. Can this be right? I mean this amplifier is pushing 400wpc compared to the 80wpc and they sound the same? please,anyone have any thoughts?

It is quite possible that 80wpc is more than adequate for your system. HK receivers actually rate conservatively so you are getting (at least) a true 80wpc. Most music reproduction only requires the _first_watt_ of that power. Remember the sensitivity measurement of your speakers? Let's say it was 90dB/W/m... that means that it only takes 1 watt to hit 90dB at 1 meter away (watts double for each 3dB increase). These large amps are only needed for low sensitivity speakers, large rooms, extreme output levels or low impedance drivers. If you never push the 80wpc receiver to it's limit then it will sound similar (some would claim identical) to the Crown amp. Only when you push the HK past its limits will you start to hear the differences with the Crown. This was the case when I compared some external amps with my Denon 5700's amp... there was no difference until very high SPLs were reached.


Why does everyone claim amazing benefits with external amplification? Either the amp in their receiver was very poor or they are deluding themselves (think cable upgrades and placebo effect). Try and differentiate between 2 amps while they are operating in their linear region... I have yet to meet a person who can accomplish this.

 

[bpape]

Hmmmm. No difference.... Don't understand why..... Yet, you own a BEAST Crown K2!? You must admit that the 'linear region' for a 400 WPC amp and an 80 WPC amp is quite a bit different.


I do agree though that the preamp section of the HK is likely not providing enough voltage to drive the Crown.


Since you had the gain on the amp all the way up, how high did you push the HK? Did you just compare levels at the same volume setting or did you try to push it harder? Did you ever see even a flicker from the amp's clip indicators?

 

[colinsm]

Just curious,

What are you using for speakers?

 

[4WR]

I think his question was answered here..... http://www.avsforum.com/avs-vb/showt...hreadid=461235

 

[Kensmith48]

I have no experience with this amp but I've heard of 250watt per channel amps requiring a 12g- 20amp circuit. Could this be the problem?

 

[tubeguy44]

Quote:

Originally posted by Kensmith48 I have no experience with this amp but I've heard of 250watt per channel amps requiring a 12g- 20amp circuit. Could this be the problem?

no

 

[M NEWMAN]

These are what you seek to remedy this problem


Best solution: http://www.rackups.com/fp-ubc2.htm


Cheap but very effective solution: http://www.rackups.com/tx-series_passive.htm#1a


Have fun...

 

[Greg_R]

Quote:

Yet, you own a BEAST Crown K2!?

Yep, but that's for my subwoofers (which fell under the "inefficient driver, extreme output levels required" section of my argument).

Quote:

You must admit that the 'linear region' for a 400 WPC amp and an 80 WPC amp is quite a bit different.

Sure, that is obvious (assuming similar measurement methods). I was wondering if he is exceeding the linear region of the 80wpc amp (if not, a bigger amp will not help).

 

[bpape]

Not necessarily. He's smart enough to run things in their linear range and desire more output (presumably WHY he BOUGHT a bigger amp to start with.)


I'm just jerkin your chain about the Crown. I figured it was a sub amp. I run a strapped Macro-Tech on my sub.