Crown amplifiers vs. other amps in the audiophile world

[lovinthehd]

Hmmm... well this is really an interesting thread. Infact i was looking for the same question and thanks to OP for posting it.
I bought my crown lately for 160$ shipped to drive my Bose 901. Earlier i was feeding them 100 wrms through my Adcom GFA 7400 but i guess 901 still required more power and potential to deliver what was expected. I found this crown CTS 600 without consulting any audiophile if it shud be the one amp with 300 wrms/channel. I bought it, plugged it, and boom. Comparing with my adcom, CTS 600 had a very warm natural sound but it started giving clipping signal to -10db when my volume was somewhere between 72 to 75 at my Denon x4400h. There i wondered if i am actually retrieving 300 watts of power to speakers that may require power amp upto 450 wrms as it was not that loud as it should be. Or purhaps sound was too much natural that i couldnt noticed it went too much high to start giving clipping signal. Fan noise was minimum but couldn't be spared in silent passages..
Then i started looking for crown amps on internet and what i found that people do not recommend PA amps in consumer place or at home ambiance. Thats heart breaking but not becaise i spent on it and hardly few people are talking about it in positive terms but that it has no place in majority of home app users..
As far as i rate crown cts 600, sound was good but left me lill shaky about its clipping signal.. so i unhooked it and started using my Adcom again...

Did you re-calibrate the avr with Audyssey when changing amp?

 

[Vacas]

Did you re-calibrate the avr with Audyssey when changing amp?

Well that's right sir. I did calibrate it but it never sound the way it should for which reason could be glass reflections... i dont know..
I plugged CTS early this month and enjoyed every bit of it for like two weeks. Probably i figured out the reason as to why clipping signal started to blink is, gain was set to full. Perhaps the intention was to get 300wrms output power ...
This is the first time for me to play around with such stuff (Commercial/PA amps) so do not know much about it. or probably i have done something wrong in setting it up not right ..
But i am certain about the sound quality which was superior than Adcom..

 

[lovinthehd]

Well that's right sir. I did calibrate it but it never sound the way it should for which reason could be glass reflections... i dont know..
I plugged CTS early this month and enjoyed every bit of it for like two weeks. Probably i figured out the reason as to why clipping signal started to blink is, gain was set to full. Perhaps the intention was to get 300wrms output power ...
This is the first time for me to play around with such stuff (Commercial/PA amps) so do not know much about it. or probably i have done something wrong in setting it up not right ..
But i am certain about the sound quality which was superior than Adcom..

If it clipped that early I think you had the gains too high.

 

[Vacas]

If it clipped that early I think you had the gains too high.

So do u advise giving cts a second chance over adcom ??

 

[PENG]

So do u advise giving cts a second chance over adcom ??

You may not be hearing the easier going harmonics from minor clipping at very high output level, but the nastier crossover distortions when the CTS amp operates in pure class B mode at near or exceed it's rated output. It is apparently not a class AB, but a class AB+B amp. I interpret that as class AB up to a point, then switch to plain class B. Some defines class AB means class A and low level and change to B at higher level. The fact is, most well designed class AB amps should be biased to ensure there is a minimum overlap such that both output transistors for their half cycles are on and conducting, to minimize crossover distortions. Some class AB amps may be designed to operate as class A for the first few watts, and in AB beyond that, while others (probably the vast majority) would operate in AB full time. Please do your own research on the topic for details, but try to stick with sites such as wiki, Elliot sounds and the likes at the minimum, to avoid the hearsay/inaccurate info that are abundant on the internet.

Since Crown called the CTS 600 a class AB+B, I suspect it is highly likely it operates in pure class B well before it reaches it's rated output. I am only guessing, to be sure, you may want to contact them for an authoritative response. That is, if you can reach their real (say level 2) tech support personnel.

 

[Verdinut]

If Crown made a class A only amp it wasn't marketed under either Crown or Amcron as far as I'm aware. But 100% interested if they did and would like a model number.

Crown's first foray into Consumer Audiphiledom would be their PS-Series. They still produce D series for studio use though expensive and doubt they sell very many units.

I thought it was in the early 1970's with the IC-150 preamp and both DC150 and 300 power amps. As a matter of fact, I had an IC-150 for a long time which I sold in the early 2000's.

 

[M Code]

I thought it was in the early 1970's with the IC-150 preamp and both DC150 and 300 power amps. As a matter of fact, I had an IC-150 for a long time which I sold in the early 2000's.

Yup... The early Crown products including the IC150 & DC300 sold very well as they were reliable crucial in pro-audio systems.. But the 1 negative point about DC300 I recall was its output stage topology being quasi-complimentary and for critical home listening applications didn't sound that good..

Just my $0.02...

 

[lovinthehd]

So do u advise giving cts a second chance over adcom ??

Just commenting on the clipping. Turn the gains down (to just where they won't clip at reference levels) and see if you still have issues. As Peng and others have indicated you may not have chosen the best amp for the job.

 

[Verdinut]

Yup... The early Crown products including the IC150 & DC300 sold very well as they were reliable crucial in pro-audio systems.. But the 1 negative point about DC300 I recall was its output stage topology being quad-complimentary and for critical home listening applications didn't sound that good..

Just my $0.02...

And I heard that it blew many PA speakers when driven to clipping levels because of its DC output content.

 

[JerryLove]

You may not be hearing the easier going harmonics from minor clipping at very high output level, but the nastier crossover distortions when the CTS amp operates in pure class B mode at near or exceed it's rated output. It is apparently not a class AB, but a class AB+B amp. I interpret that as class AB up to a point, then switch to plain class B. Some defines class AB means class A and low level and change to B at higher level.

Actually: it's a pair of Class D amps in a push-pull configuration (http://educypedia.karadimov.info/library/137234.pdf)

From their description: they are using this configuration to double the effective switching speed of the Class D

The fact is, most well designed class AB amps should be biased to ensure there is a minimum overlap such that both output transistors for their half cycles are on and conducting, to minimize crossover distortions.

Correct. both the push and pull amp in the AB are biased about 1.2v differently from one another because a transistor will conduct hardly at all if the voltage on the base is less than 0.6 volts (minus 0.6 volts for a pnp transistor). So input voltages between 0.6 and +0.6 volts will not stir either transistor into conduction.

If you don't do this: you have significant zero-cross distortion.

Some class AB amps may be designed to operate as class A for the first few watts

I think that's mostly tube hybrid amps. There's essentially a class A tube preamp backed by a class B or class AB solid-state stage. I also see Class A tubes backed by class D (you'll find a number of small amps built this way on PE).

Since Crown called the CTS 600 a class AB+B, I suspect it is highly likely it operates in pure class B well before it reaches it's rated output. I am only guessing, to be sure, you may want to contact them for an authoritative response. That is, if you can reach their real (say level 2) tech support personnel.

Or read Crown's paper on the matter (see previous link)

 

[JerryLove]

Yup... The early Crown products including the IC150 & DC300 sold very well as they were reliable crucial in pro-audio systems.. But the 1 negative point about DC300 I recall was its output stage topology being quasi-complimentary and for critical home listening applications didn't sound that good..

Why would that adversely effect sound?

 

[PENG]

Actually: it's a pair of Class D amps in a push-pull configuration (http://educypedia.karadimov.info/library/137234.pdf)

From their description: they are using this configuration to double the effective switching speed of the Class D


Correct. both the push and pull amp in the AB are biased about 1.2v differently from one another because a transistor will conduct hardly at all if the voltage on the base is less than 0.6 volts (minus 0.6 volts for a pnp transistor). So input voltages between 0.6 and +0.6 volts will not stir either transistor into conduction.

If you don't do this: you have significant zero-cross distortion.


I think that's mostly tube hybrid amps. There's essentially a class A tube preamp backed by a class B or class AB solid-state stage. I also see Class A tubes backed by class D (you'll find a number of small amps built this way on PE).


Or read Crown's paper on the matter (see previous link)

I have no idea which Crown amp you referred to, I read Crown's own description of the subject CTS 600 (see Vacas post#139) that according to them is class AB+B, not D.

Link below:

https://www.crownaudio.com/en/products/cts-600

 

[M Code]

Why would that adversely effect sound?

Because a quasi-complementary topology generated alot of IM distortion...
Very audible when played through high resolution, quality loudspeakers.. But for pro-audio applications that was more based on high SPL & reliability, IM distortion was a minor concern..

Just my $0.02...

 

[Verdinut]

Since Crown called the CTS 600 a class AB+B, I suspect it is highly likely it operates in pure class B well before it reaches it's rated output. I am only guessing, to be sure, you may want to contact them for an authoritative response. That is, if you can reach their real (say level 2) tech support personnel.

I agree in that it most likely operates in pure Class B well before ir reaches its rated output.

The effect of the crossover distortion on the output of a Class B amplifier depends to some degree on the amplitude of the output signal, the larger the amplitude, the less significant the missing 1.2 to 1.4 volt bias becomes.

True Class B amplifiers were designed to be used in pro audio applications in large venues to obtain high SPLs. Also, the distortion would be less severe at high frequencies where the rate of change of the wave, as it passes through zero is much faster, causing a shorter 'step' in the waveform:

www.learnabout-electronics.org

Those are definitely not meant to be used in a home or studio environment at low SPL levels where the crossover distortion would be easily noticeable. I presume that on the Class AB + B amps, the Class B rail is taking over at high amplitudes for a better efficiency where the crossover distortion effect would be negligible.

 

[JerryLove]

I have no idea which Crown amp you referred to, I read Crown's own description of the subject CTS 600 (see Vacas post#139) that according to them is class AB+B, not D.

Link below:

https://www.crownaudio.com/en/products/cts-600

You are correct. It looks like farther up the same line they moved to Class I. Their literature is confusing.

 

[JerryLove]

Because a quasi-complementary topology generated alot of IM distortion...

Because NPN and PNP pairs with very similar performance are available, quasi-complementary topology has fallen out of favor. To my understanding: this was the defactor for most of Class B / AB's life.

Can you point me at some scholarly work supporting the claim?

Very audible when played through high resolution, quality loudspeakers.. But for pro-audio applications that was more based on high SPL & reliability, IM distortion was a minor concern..

So "pro-audio" is low "resolution" and low "qualty"? Care to support? I can name a pro speaker or two we can use as reference if you like.

 

[GrimSurfer]

Because a quasi-complementary topology generated alot of IM distortion...
Very audible when played through high resolution, quality loudspeakers.. But for pro-audio applications that was more based on high SPL & reliability, IM distortion was a minor concern..

Bingo!

Those are definitely not meant to be used in a home or studio environment at low SPL levels where the crossover distortion would be easily noticeable.

Bingo again!

 

[GrimSurfer]

So "pro-audio" is low "resolution" and low "qualty"? Care to support? .

Sure. Easy.

It's designed for a different set of conditions than home use. Want proof? It (public address) is in Crown's product literature.

 

[JerryLove]

Sure. Easy.

It's designed for a different set of conditions than home use. Want proof? It (public address) is in Crown's product literature.

I have a milkshake maker designed for commercial restaurant use in my house. Therefore my milkshakes are bad?!?

To truly show that it's "bad for application X" will require measurments.

But even if I ignore that and accept a presupposition "built for Y", you need to illustrate why the needs of Y are incongruent with X.

What is a *requirement* of a PA amplifier that prevents it from being a good home-use amplifier?

In what way does "designed for PA" require that the resolution be low?
In what way does "designed for PA" require that the quality be low?

Someone once said:
Subjectivity is the quality based on or influenced by personal feelings, tastes or preferences. Opinions are subjective.
Objectivity is the quality of being true independent of perception, emotions, or imagination. Science, measurement, and derivatives support assessment which is objective.

Do you have some science or measurements which objectively establish "low resolution" and "low quality"? Can you even give a falsifiable definition of those terms? How do we measure "resolution"? How do we measure "quality"?

 

[Alex2507]

I have a milkshake maker designed for commercial restaurant use in my house. Therefore my milkshakes are bad?!?

If you like the way your milkshakes sound, that's all that matters.