QSC MX3000a POWER AMPLIFIER VS. CROWN REFERENCE I STUDIO POWER AMPLIFIER

[E-Stat]

Crown seems to take it's share of lumps because it's too cheeep and doesn't have that high-end (read: "fancy") mystique...

Crown has always had a particular taste for high negative feedback designs. The DF of the Studio Reference line is 20,000, suggesting that habit continues unabated. The usual result is less than ideal high frequency performance. I also question the thoroughness of a minimum 1.6 kilowatt amp that weighs only sixty pounds. My 200 watt Threshold amp weighs about the same.

To each his own.

Enjoy a long and safe weekend yourself. I'm going to work on completing my DIY tube traps and naturally, listen to some muc-sic as well.

rw

[FLZapped]

Crown has always had a particular taste for high negative feedback designs. The DF of the Studio Reference line is 20,000, suggesting that habit continues unabated. The usual result is less than ideal high frequency performance. I also question the thoroughness of a minimum 1.6 kilowatt amp that weighs only sixty pounds. My 200 watt Threshold amp weighs about the same.

Nothing wrong with feedback when properly applied, and I believe Crown knows how to do that, certainly their specs don't show any anomolies.

To each his own.

Enjoy a long and safe weekend yourself. I'm going to work on completing my DIY tube traps and naturally, listen to some muc-sic as well.

rw

Well, it's long alright. Been out of work since Thursday and preparing for Frances to drop by.....

-Bruce

[pelly3s]

I also question the thoroughness of a minimum 1.6 kilowatt amp that weighs only sixty pounds. My 200 watt Threshold amp weighs about the same.
rw

Crown has been using light weight coils for their transformers instead of iron core transformers in the power supplies. along with light weight chassis. crown amps are used in studios be it the reference series, the k series or the d series. if you are against pro amps being used as home amps then do you have a problem with the Hafler P series (or 90% of the Haflers ever made), Chord, Bryston, Hot House, or Manley. All those companies fall into the pro category making mostly studio amps.

[E-Stat]

Nothing wrong with feedback when properly applied, and I believe Crown knows how to do that, certainly their specs don't show any anomolies.

Except of course for the astronomical DF. THD always looks better on paper when high levels of NF are used. Partially responding to pellys comment regarding other pro amps, lets look at some comparative numbers:

MODEL-----------------------------DAMPING FACTOR-------------------WATTS--------------WEIGHT
Crown Studio Ref1------------->20,000 or >2500(1khz)---------------1600--------------------61
Bryston 7B------------------------------300--------------------------------------600---------------------50
Chord SPM600------------------------266---------------------------------------600---------------------88
Manley NeoClassic------------------13(tube)--------------------------------250---------------------73
Passlabs XA-200----------------------30---------------------------------------200---------------------175

I realize that increasing the number of output devices can lower output impedance and thus increase DF. The XA200 has (32) MOSFET outputs, so apparently this factor alone is not significant. What design factors other than using high levels of global feedback are there to get such a low source impedance?

Well, it's long alright. Been out of work since Thursday and preparing for Frances to drop by.....

The current weather map for the Ft. Lauderdale area looks, well very green. Hang in there!

rw

Damping Factor

[FLZapped]

What design factors other than using high levels of global feedback are there to get such a low source impedance?

It also has to do with the electrical characteristics of the devices used, the output topology, including what may have been placed in the output after the output devices, such as oscillation suppression circuits and transformers.

I noticed that the XA is listed as a class A amplifier, that is why it's damping factor is so low. (Output topology)

In the case of Bryston, they have a pretty high output frequency listed as the top of their bandwidth, this also affects DF.

-Bruce
(Now getting aquainted with Frances)

[E-Stat]

It also has to do with the electrical characteristics of the devices used, the output topology, including what may have been placed in the output after the output devices, such as oscillation suppression circuits and transformers.

I see three overall possibilities:

1. Crown has discovered something that no other amplifier designer has.

2. The design and device characteristics resulting in an extremely high DF have no deleterious effect on overall musical reproduction.

3. Crown chose to optimize the amp for a different result.

Here is their explanation:

"They also feature a damping factor of better than 20,000 for absolute speaker control with a tight, well-defined low end."

I would vote for answer # 3.

rw

[FLZapped]

I see three overall possibilities:

"They also feature a damping factor of better than 20,000 for absolute speaker control with a tight, well-defined low end."

I would vote for answer # 3.

rw

Gee, I could use a tight well defined low end.....wonder if it would work for me too.....


-Bruce
(STILL dancing with Frances)

[jbangelfish]

Between the two, I'm sure I'd pick the Crown having had a decent Crown amp in the past but I'd try to audition both of them. If I had unlimited funds, I'm sure I'd pick the Pass Labs mono blocks but I don't think he asked about them as they are probably not in his budget.
Just a thought.
Bill
PS, I'm not sure what to make of the extreme DF of the Crown, I'd like to hear it for myself. I'm now using amps that have DF of 1,000 and am not sure of the benefit. Yes, the bass is tight but I'd like to hear true high end components with the low DF and make a direct comparison. Have not done so.The old Crown (DC300A had over 700). I've had amps with DF of 100 and did not care for them but I'll be the first to admit that they were not great amps anyway. Accuphase integrated and a pair of Sony ES, bridged mono. More to ponder.

[RGA]

Firstly since no one has asked - what do you think of the sound of the two amps with your speakers versus the ATI. ATI is no slouch actually and there will be no audible difference going from 350 watts to 400watts all else being the same.

High Damping factors come with high negative feed-back. UHF magazine - yes I know - recommends avoiding amplifiers with damping facors much higher the 40. But they are about home high end audio - not necessarily the real world. Before jumping on them for saying it e-mail them and get more of a reason why - they state this on 77 of their book.

Of course you are talking to a person who just heard a 9 watt Single Ended amp and walked away getting more deeper tight bass and more extended grain free highs than the Bryston 3BST could muster with the appropriate speaker. No mid range euphoic warmth, no noise, no hum, and played at soft or very loud levels with astounding macro and micro dynamics.

Granted you speaker may need more power - Crown? Post at http://www.audioasylum.com/forums/amp/bbs.html for some more takes on Crown.

[FLZapped]

Firstly since no one has asked - what do you think of the sound of the two amps with your speakers versus the ATI. ATI is no slouch actually and there will be no audible difference going from 350 watts to 400watts all else being the same.

.

I agree, ATI, formerly SAE, makes some excellent amps.

-Bruce