Whatcha think about "pro" amps from Crown, QSC, etc?

[Rednaxela]

man those are *ugly*

Hear hear!

 

[mhardy6647]

In the case of the D150 and (especially) the IC150, they're ugly not very attractive -- and they sound pretty bad, too.
They are pretty beefily constructed, though -- and the documentation for them is fun to read.

 

[Jmudrick]

But that's the point - buying a product which is suited to purpose from the start means you don't have to go through the trouble of rigging a DIY solution.

I might ask the question - why is a pro amplifier more suited for home use than a good amplifier specifically designed for the home? Can anybody answer this question?

I've answered this a couple times already . Crown XLS combination of power, functions like adjustable high/low pass, and multiple output (for sub) make it an attractive proposition at going price for systems with subs and monitors benefiting from the configuration. My Buckeye system works fine in a similar 2.2 configuration because it utilizes subs with built-in high pass, the two Crown system are used where the subs don't provide this. I prefer the Crowns to adding yet another box for DSP or using an unnecessary complex and bulky AVR with far less power.

 

[MakeMineVinyl]

I've answered this a couple times already . Crown XLS combination of power, functions like adjustable high/low pass, and multiple output (for sub) make it an attractive proposition at going price for systems with subs and monitors benefiting from the configuration. My Buckeye system works fine in a similar 2.2 configuration because it utilizes subs with built-in high pass, the two Crown system are used where the subs don't provide this. I prefer the Crowns to adding yet another box or using an unnecessary complex AVR with less power.

You're still using features which do not exist in a typical setup. You're buying features which are particular to your situation - just like I do - but for the average person who wants the best performance and isn't concerned about getting 400w for $250? Usually such a person would buy an AVR or something like an HTP-1 processor and an 8 channel class D amp.

 

[Jmudrick]

You're still using features which do not exist in a typical setup. You're buying features which are particular to your situation - just like I do - but for the average person who wants the best performance and isn't concerned about getting 400w for $250? Usually such a person would buy an AVR or something like an HTP-1 processor and an 8 channel class D amp.

Moving on.

 

[jhaider]

I might ask the question - why is a pro amplifier more suited for home use than a good amplifier specifically designed for the home? Can anybody answer this question?

I think that’s a reasonable question. I think the answer is “it’s generally not” with the following exceptions:

1) Your speakers require the DSP built into a specific pro amp. Examples are JBL 7-series install and M2 with Crown, but also e.g. the Grimani speakers tested here, that use a Powersoft DSP-amp.

2) You want voltage swing for days in an application where the last word in SNR isn’t key. Subs are an obvious choice here

3) Your gear is in a remote 19” rack and you don’t care about fan noise. While some consumer amps offer rackable faceplates (e.g, ATI or Bryston) many are not.

There are probably other reasons but those are IMO the big ones.

 

[MakeMineVinyl]

I think that’s a reasonable question. I think the answer is “it’s generally not” with the following exceptions:

1) Your speakers require the DSP built into a specific pro amp. Examples are JBL 7-series install and M2 with Crown, but also e.g. the Grimani speakers tested here, that use a Powersoft DSP-amp.

2) You want voltage swing for days in an application where the last word in SNR isn’t key. Subs are an obvious choice here

3) Your gear is in a remote 19” rack and you don’t care about fan noise. While some consumer amps offer rackable faceplates (e.g, ATI or Bryston) many are not.

There are probably other reasons but those are IMO the big ones.

My use of a pro amp fits #2 and #3. The amp is used for subs (four in stereo config) and the amp is in the amp closet with the active crossovers and surround amp. Loads of power, but on the bench, that power is a bit trashy compared to a good class A/B or even a Hypex. That doesn't matter for subs.

 

[gnarly]

Fully agree that many/maybe most, of the proamp features I find valuable as a DIY speaker builder, are not needed (or even wanted) by a typical home audio user.

I think there's probably widespread agreement that proamps are a good fit with home audio fit systems using separate subs.

So stepping away from that particular use, I ask myself what are the features that proamps have, that are missing from and sorely needed in consumer amps.

Top of my list is clip limiting. Close to essential.
10X so for consumer amps driving passive speakers..... (which i guess is probably the majority of home amps).

Maybe next would be the standard set of protection circuits that come with proamps.
Short circuit / low impedance protection, etc. And instant-off muting without any damn transients. ( I abhor amp bleed-down on power off)


I think that set of features would only cost a few more bucks to implement.
Definitely worth more than 'bling' in my book; also worth more to me than pursuing SINAD past a reasonable point...

 

[MakeMineVinyl]

Maybe next would be the standard set of protection circuits that come with proamps.
Short circuit / low impedance protection, etc. And instant-off muting without any damn transients. ( I abhor amp bleed-down on power off)

I'm the person who designs the protection circuits for all of our power amplifiers, both pro and consumer. Long story short, they are identical. All of them use microcontrollers in conjunction with multiple layers of opto couplers, current sensors, and temperature sensors. All faults will initiate different levels of response, with the most serious completely removing power and locking the amplifier in a safe state until the AC is removed and the situation resolved. None of the fault conditions will cause transients or 'bleed down' of sound in the output. The sensors which created the fault get logged in non-volatile memory in the microcontroller so that the fault codes can be evaluated by the factory.

I don't expect that we are unique, and I know as fact that many or most consumer power amplifiers from other manufacturers utilize fail-safe protection schemes. Doing so does not cost a lot of money in parts or development time. Manufacturers like us realize that the cost of an amplifier causing damage to other gear or property far outweigh the cost of a good protection scheme.

Our pro amplifiers all include clipping protection, and a few of our consumer amplifiers do also. But we stress to potential consumers the importance of sensible amplifier power selection - that of buying enough power in the first place so that clipping does not occur.

 

[gnarly]

I'm the person who designs the protection circuits for all of our power amplifiers, both pro and consumer. Long story short, they are identical. All of them use microcontrollers in conjunction with multiple layers of opto couplers, current sensors, and temperature sensors. All faults will initiate different levels of response, with the most serious completely removing power and locking the amplifier in a safe state until the AC is removed and the situation resolved. None of the fault conditions will cause transients or 'bleed down' of sound in the output. The sensors which created the fault get logged in non-volatile memory in the microcontroller so that the fault codes can be evaluated by the factory.

I don't expect that we are unique, and I know as fact that many or most consumer power amplifiers from other manufacturers utilize fail-safe protection schemes. Doing so does not cost a lot of money in parts or development time. Manufacturers like us realize that the cost of an amplifier causing damage to other gear or property far outweigh the cost of a good protection scheme.

That's all very good news to me.....thanks for the info. Glad to hear what seems to be becoming mainstream.
All my home audio amps date back to the 90's and earlier.......pure analog stuff ......guess i need to catch up home-audio wise, on today's implementations.

Our pro amplifiers all include clipping protection, and a few of our consumer amplifiers do also. But we stress to potential consumers the importance of sensible amplifier power selection - that of buying enough power in the first place so that clipping does not occur.

Yeah, that makes good sense, at least on paper I think....I just doubt how diligent folks are on heeding your advice...especially when trying out / moving up to different speakers (larger)

So, I do believe consumer amps driving passives need a clip limiter. Too many burnt tweet stories.
And every time i push a few numbers, sensitivity & amp power vs SPL with required unclipped headroom...it gets hard to imagine clipping isn't occurring when folks turn it up.

 

[MakeMineVinyl]

So, I do believe consumer amps driving passives need a clip limiter. Too many burnt tweet stories.

There are however very real marketing downsides with including clipping protection - which is really a hard limiter which kicks in at a certain point. Like it or not, 'audiophiles' typically will not purchase amplifiers which include such circuitry. In a typical home theater environment, subwoofers are used; subs are the speakers which have by far the largest power demands. Relieved of the need to power a subwoofer, the main power amplifier channels do not need as much power as one would think, so there is less potential for clipping with real-world program material and at standardized SPL levels for movies.

Ours typically starts to kick in at around 1% distortion (the circuit actually measures input vs output distortion; it isn't simply triggered at a particular output voltage).

Amplifiers of the 90s and earlier were really the stone age of protection circuitry, and were often 'protection' on paper only. Many used physical relays on the speaker outputs, and while these worked OK normally, the contacts tended to arc closed at the most inopportune times - like a dead short of an output transistor. This of course dumped full rail voltage into the speaker's woofers. To address the arcing, magnets were frequently placed on the sides of the relays to draw the arc away from the contacts. That rarely worked as advertised.

 

[gnarly]

There are however very real marketing downsides with including clipping protection - which is really a hard limiter which kicks in at a certain point. Like it or not, 'audiophiles' typically will not purchase amplifiers which include such circuitry.

I don't pretend to have your experience with how most amp limiters work.
The limiters in all the various QSC amps that i've put on a scope, don't hard limit.
They pretty much maintain the waveform's shape, but hold it to a certain max level.
So not at all like digital clipping banging into 0 DBFS.
I thought the QSC type clip limiting would be norm in all proamps.

I too couldn't live with hard clipping; and i don't think live or commercial install could either.
So it's kinda hard to imagine a proamp amp even having hard clip limiter.. But maybe some do?????

In a typical home theater environment, subwoofers are used; subs are the speakers which have by far the largest power demands. Relieved of the need to power a subwoofer, the main power amplifier channels do not need as much power as one would think, so there is less potential for clipping with real-world program material and at standardized SPL levels for movies.

Yep, IF there's a sub. Big IF . So much home audio is not HT....and/or without a sub.

I don't think I can be convinced clip limiters shouldn't be standard in all amps .....

Ours typically starts to kick in at around 1% distortion (the circuit actually measures input vs output distortion; it isn't simply triggered at a particular output voltage).

Where does that usually relate to maximum rail voltage? Curious, have not heard of that type of amp limiting before.
What types of distortion, THD ? IMD? Total or by frequency? I can't imagine it's by frequency.....



My main audio hoppy besides speaker building, is speaker processing... (mostly FIR tuning)
But here's a limiter i built for a vented sub that ran into over excursion well above its low corner.
It applies both level and frequency dependent limiting, via a sidechain implementation.

At lower levels, it has almost no hpf, then at increasing levels as shown, applies both more high pass and increasing parametric cut.
My only foray into custom limiting,,,,.

 

[MakeMineVinyl]

I don't pretend to have your experience with how most amp limiters work.
The limiters in all the various QSC amps that i've put on a scope, don't hard limit.
They pretty much maintain the waveform's shape, but hold it to a certain max level.
So not at all like digital clipping banging into 0 DBFS.
I thought the QSC type clip limiting would be norm in all proamps.

I too couldn't live with hard clipping; and i don't think live or commercial install could either.
So it's kinda hard to imagine a proamp amp even having hard clip limiter.. But maybe some do?????


Yep, IF there's a sub. Big IF . So much home audio is not HT....and/or without a sub.

I don't think I can be convinced clip limiters shouldn't be standard in all amps .....

Where does that usually relate to maximum rail voltage? Curious, have not heard of that type of amp limiting before.
What types of distortion, THD ? IMD? Total or by frequency? I can't imagine it's by frequency.....



My main audio hoppy besides speaker building, is speaker processing... (mostly FIR tuning)
But here's a limiter i built for a vented sub that ran into over excursion well above its low corner.
It applies both level and frequency dependent limiting, via a sidechain implementation.

At lower levels, it has almost no hpf, then at increasing levels as shown, applies both more high pass and increasing parametric cut.
My only foray into custom limiting,,,,.

View attachment 219199

By "hard limiting" I did not mean the signal turns into a square wave. What I meant by hard limiting is that the waveform stays the same but refuses to increase in amplitude by very much as input voltage is increased.

The distortion detection in our amps is something I developed. I can't go into it much because its proprietary, but it works very well at responding to actual signal conditions, and it detects all forms of distortion.

Regarding the decision to include clip limiters in all consumer amps - you can do that if you ever go into amplifier manufacturing.

 

[Randy Bessinger]

Is the cost to markup the same in the pro world as the consumer world or does it just depend?

 

[MakeMineVinyl]

Is the cost to markup the same in the pro world as the consumer world or does it just depend?

It depends. Most pro amps nowadays are churned out in quantity from plants in Asia, and that is the major reason they can be so cheap. A byproduct of this is that parts quality is not necessarily top notch. These pro amps are not the same quality or as rugged as the pro amps of yore like the Crown DC150 which were made in the U.S., or ahem, ours.

There's nothing magic about these inexpensive pro amps - you still ultimately get what you pay for.

 

[Jaxjax]

I'll take my $250. Yamaha P2500S over most any consumer amp at 10x the cost & probably much higher then that. The P2075 I run in bedroom is superb. The Pascal I run in my active rig is the best playback I have ever achieved. I also can not stand RCA jacks & xlr is just my happy. Binding posts for that matter piss me off...lol I also like to run analog pro parametric's & wouldn't be without one, so consumer gear is mostly out for me. Serious deals to be had on A/B pro amps now as everyone is down the class D path. If I had the funds it would be all ATC, Nuemann & Dynaudio active monitors in house & no outboard amps. I'm 1/2 way there

 

[MrKlinky]

My only experience is with used QSC amps - nothing but trouble with every one of them and sold them all for spares and cannot recommend. Have owned many second/third/fourth-hand Behringer EP2500 amps for 20 years or so without a single glitch. Go figure...

 

[mhardy6647]

My only experience is with used QSC amps - nothing but trouble with every one of them and sold them all for spares and cannot recommend. Have owned many second/third/fourth-hand Behringer EP2500 amps for 20 years or so without a single glitch. Go figure...

Perhaps they were, as some would say, rode hard and put away wet.

 

[gnarly]

Perhaps they were, as some would say, rode hard and put away wet.

Haha.,,,.probably so, real hard! Lol.

Because afaict, QSC appears to have the best long tern reliability reputation among the mainstream prosound manufacturers.. (live, threatre, install, etc)

 

[mhardy6647]

Haha.,,,.probably so, real hard! Lol.

Because afaict, QSC appears to have the best long tern reliability reputation among the mainstream prosound manufacturers.. (live, threatre, install, etc)

My impression is similar (although not particularly well informed), FWIW.
Their products are on the expensive side relative to the myriad competitive brands, which I figure that QSC can only get away with if they have something going for them.