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Crown XLi 800 Power Amplifier Review

dropbear

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He ran a lot of equipment of XLS models at RAMF this year and the sound impressed a lot of people, including those not Zeos fan boi's
I think it was because he brought RMAF-youraverage20kpowercables-unknown type of products and they wondered how is it possible that some speakers sound better than their 148-tweeter array speakers.
 

RayDunzl

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60lb Krells?

Yup.

"Entry Level", as they say.

1571313760044.png

But monoblocks, so x2.

I like this set of build photos on these later and bigger devices, though:

https://wizard-highend.blogspot.com/2012/01/building-up-of-krell-400e-mono-amp.html


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That's not to say I don't appreciate the Hypex/nCore stuff.
 
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anmpr1

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The other amp that came to mind was the $3,000 "high-end" high-fidelity "pro-audio" Class-AB amp - the AHB2 from Benchmark. In @amirm's review, he stated that "You get 500 watts of stunningly clean power." It is an "airbox," but unlike many of the larger Hypex and ICEpower amplifiers, the AHB2 has a reason for all of the empty space inside the chassis - the HUGE cooling fin area. I am guessing that the extra height is primarily to accommodate the fins and facilitate better convective (passive) cooling.
With pretty sensitive speakers the AHB2 never gets more than slightly warm, I'd say it runs cool to the touch--at least in a home setting playing music as loud as you want to listen to for extended periods of time. In a more demanding situation, I can't say. For me it is overbuilt. With low impedance inefficient speakers? Likely a different story. In any case, it is a little amp, form-factor speaking.

PS: with a DAC3, volume turned all the way up, there is no hiss at all. Very quiet.
 

GrimSurfer

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Yup.

"Entry Level", as they say.

View attachment 36198

But monoblocks, so x2.

I like this set of build photos on these later and bigger devices, though:

https://wizard-highend.blogspot.com/2012/01/building-up-of-krell-400e-mono-amp.html


View attachment 36191

View attachment 36192

View attachment 36193

View attachment 36194

View attachment 36195

View attachment 36196

View attachment 36197

That's not to say I don't appreciate the Hypex/nCore stuff.

6000W power consumption on the 750Mc? So I guess you need a coupe of 50A circuits to run a pair of these, though they would probably fill any large welding shop with sound.
 
OP
amirm

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I can't seem to find anywhere in the specs that calls this a class B amplifier, I would have thought it is class AB?
It is class AB. Somehow I left out the letter A out of that which I just corrected. Class B amps are only used in RF amplifiers and such. I don't know of any class B audio amplifiers.
 

LTig

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I found this picture of its guts:

HTB1GdsDSpXXXXXdXXXXq6xXFXXXO.jpg


I don't see a pot on it to adjust but it may be hidden.
What about those two parts (circled)? At least the lower one looks like a trim pot which has been sealed with some kind of wax.
XLI800zoom.jpg
 

pma

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It is class AB. Somehow I left out the letter A out of that which I just corrected. Class B amps are only used in RF amplifiers and such. I don't know of any class B audio amplifiers.

Well, that's a matter of terminology. Douglas Self would not agree with you.

https://www.eetimes.com/document.asp?doc_id=1274886&page_number=3

http://www.douglas-self.com/ampins/dipa/dipa.htm

The distortion produced by a typical solid-state Class-B power amplifier is shown to consist of eight mechanisms, all of which may co- exist and whose distortion products overlap to give a complex result. Methods for isolating each mechanism for study, and minimising its contribution, are given. If the avoidable distortions are designed out, Class-B amplifiers of unusually low distortion (Below 0.0005% at 1kHz, 0.003% at 10 kHz) may be designed as a matter of routine, and without significant extra cost. Such amplifiers define a distortion benchmark, and I have named them "Blameless" amplifiers.

To him, class B is optimally biased class AB (Vre about 25mV).
 

KozmoNaut

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It is class AB. Somehow I left out the letter A out of that which I just corrected. Class B amps are only used in RF amplifiers and such. I don't know of any class B audio amplifiers.

The QSC GX3 is listed in the official spec sheet as class B, that's why I was wondering :)
 

GrimSurfer

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The QSC GX3 is listed in the official spec sheet as class B, that's why I was wondering :)

Which is why independent confirmation of what manufacturers put on the spec sheet is so important.
 

bravomail

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Conclusions
Crown advertises the XLi 800 as a PA (Public Address) amplifier and that is what it is. Distortion and noise is kept in check just enough to do the job with tons of power for so little money. I suspect it is reliably too given the dual fans to keep it cool. And the market it is being sold into.

For hi-fi use, it is not something I would consider to drive full-range speakers. For subwoofer or active woofer duty, it would be fine.

As it is, I can't recommend the XLi 800.

Thx for review, Amir! It should be clear that you don't recommend this device for Hifi, as it seems to function per spec (or slightly better) and will work fine for public announcements. I mean lots of power and lots of distortion - typical megaphone use case! "Pls disperse or my mom will shoot!" :)
 

Cahudson42

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Anyone have the service manual/schematic for this thing? It would be interesting to see if there are bias trim pots, and then push the bias up to see if the distortion reduces..

As an aside, it seems at least one AVR manufacturer, Onkyo, is removing bias pots from current AB products, though they are in earlier year models. The Onkyo tx-rz720, which I have, shows the trim pots in the scheme, but as 'NM' (Not Mounted, I assume). They also are missing from the parts list. 'Interesting' solution to their earlier heat problems - under-bias and don't let anyone change it. Great engineering - reminds me of Honda's VCM - Variable Cylinder Management - garbage engineering...
 

RayDunzl

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Give me those Krells any day.

I occasionally see the set - amps, pre, and remote - asking price (used) the same as I paid nine years ago...

Sometimes when Audio Buddy comes over for Beer Saturday, and some particularly engaging musical moment has just passed, he'll say:

"The Krells Speak."


6000W power consumption on the 750Mcx?

That's what it says...

1571343216885.png
 

RayDunzl

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In the classic 1956 science fiction film Forbidden Planet, the extinct race of advanced beings of the planet Altair IV are known as the Krell. They were destroyed by their own technology.


I suppose the pertinent question is asked at 3:10 - "What's it all for?"
 
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