No pro amp looks cooler than Crown 3600VZ imo.
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Whatcha think about "pro" amps from Crown, QSC, etc?
- Thread starter Chrispy
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That looks very nice on the shelf!
>Most pro amps nowadays are churned out in quantity from plants in Asia
Lab.Gruppen now assembles amps in Thailand instead of Sweden. Have only seen two amps with assembly mistakes yet (out of ~400)...
We own >10 QSC CX series amps which we use for PA they have only failed when VGA cables which short the dataport connectors where used on the dataports this apparently caused PSU failure. Looking at the dataport pinout there is a +15V aux supply out so probably that was shorted. The afflicted amps are all fixed and continue to work.
+1 as their is no real standard about levels .
But many hypex and purifi implementers does bring gain control/input sensitive adjustment with their offerings nowadays
so at least this home market segment is implementing some of this . Clipping indicators ? I think some class-D modules supports that ? not sure who has them. But these commercial modules has all kind of protection.(maybe the ruggedness and reliability is not up to pro use , hence why we don't see hypex all over the pro market ? )
benchmark have clipping indicator in their AHB2 .
I agree these are needed features all but absent in the old style hifi power amp of the past , with some exceptions . I once had an old GamuT amp with gain selections.
Looks like car hifi
Sokel
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Ice power Edge has everything you can imagine to show it's status,clipping is the last.And it's not the only ones I think,Hypex and Purifi has as well.+1 as their is no real standard about levels .
But many hypex and purifi implementers does bring gain control/input sensitive adjustment with their offerings nowadays
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With Purifi, the input gain is controlled by the "buffer"--really the first-stage amplifier. They come in various gain values, and some provide several choices. I think Buckeye, for example, is using an input buffer with several input gain choices for the Purifi amp.
Hypex is the same except for their all-in-one MP (mains-powered) models, which is what Buckeye sells. Those provide a single fixed gain of 25.5 dB. But the modules support clipping indicators whether or not the implementer makes use of the feature. Buckeye, for example, now uses a custom interface board that provides clipping indicators. Rick Sykora installed clipping indicators in my Buckeye NC502MP before it was shipped to me, and they are really nice to have.
Commercial amps also often have an input signal indicator, which I like. I've never seen that on a home amp. In the one commercial sound system I manage, the amp is not close at all to the control desk, and I sometimes use binoculars to check the indicators on the front of the amp, which is visible to me from about 50 feet away. If I'm trying to troubleshoot something during a church service, that is pretty useful information. But that is for a sound reinforcement system that works at a very subtle level, and even I can't always be sure the system is working. My goal was for people not to sense a PA system at all, but to be able to hear clearly. I'm not sure that feature is useful in the home environment where if the amp isn't working, silence ensues.
In a commercial amp, analog power meters seem to me to have precisely zero value, especially if the amp is supplied with signal and clipping indicators. But they sure do look nice in a home amp (even though they don't provide much useful information there, either).
Rick "all of whose commercial amps have input-gain controls on the front panel" Denney
Hypex is the same except for their all-in-one MP (mains-powered) models, which is what Buckeye sells. Those provide a single fixed gain of 25.5 dB. But the modules support clipping indicators whether or not the implementer makes use of the feature. Buckeye, for example, now uses a custom interface board that provides clipping indicators. Rick Sykora installed clipping indicators in my Buckeye NC502MP before it was shipped to me, and they are really nice to have.
Commercial amps also often have an input signal indicator, which I like. I've never seen that on a home amp. In the one commercial sound system I manage, the amp is not close at all to the control desk, and I sometimes use binoculars to check the indicators on the front of the amp, which is visible to me from about 50 feet away. If I'm trying to troubleshoot something during a church service, that is pretty useful information. But that is for a sound reinforcement system that works at a very subtle level, and even I can't always be sure the system is working. My goal was for people not to sense a PA system at all, but to be able to hear clearly. I'm not sure that feature is useful in the home environment where if the amp isn't working, silence ensues.
In a commercial amp, analog power meters seem to me to have precisely zero value, especially if the amp is supplied with signal and clipping indicators. But they sure do look nice in a home amp (even though they don't provide much useful information there, either).
Rick "all of whose commercial amps have input-gain controls on the front panel" Denney
Matthias McCready
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Sounds like it might be time to move to some networked amps.
It is quite nice to be able to see how your amps are doing on a FOH computer real-time (gain, headroom, limiting etc).
The newer amps from the "big three" tend to tell you if your boxes and individual drivers are happy as well, granted one of the big three only builds powered/active boxes, so that gives them an edge, and probably doesn't qualify for this discussion.
I would at least like to network in the DSP EQ—a dbx PA2—which does support it. But this is an ultra low-cost system and it’s not my money I’m spending.Sounds like it might be time to move to some networked amps.
It is quite nice to be able to see how your amps are doing on a FOH computer real-time (gain, headroom, limiting etc).
The newer amps from the "big three" tend to tell you if your boxes and individual drivers are happy as well, granted one of the big three only builds powered/active boxes, so that gives them an edge, and probably doesn't qualify for this discussion.
Rick “and no low-voltage wiring in the building” Denney
I test a lot of PA amp systems. A newly-annoited System Engineer was hanging out when I was noising the rig. He mildly freaked out when he saw “load fault” flash everywhere. Well yea, all output connectors are open ha, load fault is a “good” indicator in that circumstance. Amps from Sweden, still with banana plugsSounds like it might be time to move to some networked amps.
It is quite nice to be able to see how your amps are doing on a FOH computer real-time (gain, headroom, limiting etc).
The newer amps from the "big three" tend to tell you if your boxes and individual drivers are happy as well, granted one of the big three only builds powered/active boxes, so that gives them an edge, and probably doesn't qualify for this discussion.
D
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I like my old pro Yamaha P3200. It sounds better than Yamaha MX-630 / Yamaha RX-V3800. A comparison (not blind A/B) between the P3200 and Yamaha A-S1000 is undeterminable until the volume gets high, then the pro amp is keeping the sound much more clean. Some distortion must be present at higher SPL on the A-S1000.
My speakers have 7 drivers each, though small in diameter. The sensitivity is 90 dB@1 m. but I have a suspicion that it's a great deal lower than that. They can take a lot of power.
I think the Yamaha P3200 is quite classy to look at. This picture is an old one where I had the top cover lifted a bit with washers and deactivated the always-on fans. Now it's completely surface mounted again and the fans wired in series to lower the noise to near-silent level.
To get comparable power, quality and dampening factor, I would have to invest some serious money.
My speakers have 7 drivers each, though small in diameter. The sensitivity is 90 dB@1 m. but I have a suspicion that it's a great deal lower than that. They can take a lot of power.
I think the Yamaha P3200 is quite classy to look at. This picture is an old one where I had the top cover lifted a bit with washers and deactivated the always-on fans. Now it's completely surface mounted again and the fans wired in series to lower the noise to near-silent level.
To get comparable power, quality and dampening factor, I would have to invest some serious money.
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Funny enough saw a Yammy console PSU the other day that looks nearly identical, less the knobs and plus mains voltage 7-segments. Love the utilitarian design- biga$$ handles and recessed knobs. I see plenty of broken knobs (for rotary encoders) these days cause there ain’t enough room to recess them..
Add my 2c...
I read many reviews when the Crown XLS became a bit of a "cause celebre" in the Audiophile world, circa 10 years ago when Andrew Robinson replaced audiophile amps in his home theatre setup with a batch of XLS power amps, and then raved about their sound quality.
This triggered a bunch of people trying them out, with feedback of various types (yes ranging from - "absolute cr@p" to "Wow, Fantastic!" )
At the time a used XLS2500 could be picked up for US$250... , and I picked up 2 of them to try out for Biamping, and Bridging as well as straight stereo use
So about the XLS2500...
Power... although very high, the power is measured professional style as a 1kHz signal continuous, rather than 20-20khz... so you can discount the official figures by 20% to be safe...
440W @ 8ohm (Conservative 350W)
775W @ 4ohm (Conservative 620W)
1200 W @2ohm (Conservative 960W)
They can be bridged and get close to 2500W (hence the model name I believe) into 1 ohm
So here you have a very economical, (downright cheap! at the time...) power amp, capable of, in domestic terms, limitless power, and possibly more importantly, effectively limitless current (1000W @ 2ohm !!!)
Worthy of note: - it is a Class D design, and headroom above and beyond the rated spec is probably limited... so, unlike Class AB amps, you can't assume peak (time limited) headroom above and beyond the base spec.
How does this matter - well quite a few of us, have speakers which have complex and difficult impedance curves, in some cases dropping down to 1 ohm (certain Electrostatic speakers eg: ML) - and in many cases dropping below 3 ohm - particularly for the bass, where serious power is required, in addition to substantial current to handle the low impedance.
Additionally - the built in DSP with flexible crossovers, low pass and high pass filters allows for very easy biamping, driving of subwoofers, etc...
So those are the positives... (and applicable to quite a few pro amps)- what are the negatives?
First thing many audiophiles point to... it has a Fan.
Yes it does. and whether the Fan is audible or not, may be associated with multiple parameters - first being the noise floor in the listening room, second being how hard it is being driven, and whether it is "warming up".
Given it's HUGE power reserves, it is very very rare, that in any domestic situation, a set of these amps will go anywhere beyond idling.
This means that under 99% of consumer use circumstances - these will barely get warm, never hot - and the fans will either not turn on, or be barely ticking over.
My own experience: - with 88d SPL/wm - the signal LED (-20db from rated) - barely lights up on peaks at normal listening - that implies a touch over 3W continuous.... on Movie effects peaks - it may get to the -10db LED - which amounts to circa 50W... and that is when it is definitely too loud, and needs to be turned down... - so the amps are really only ever idling... and so are the Fans.
I have never heard the fans. (note: my listening area is also the family area, and base noise levels are not fantastic, even at the best of times, so Fan noise may be covered up)
Moving on, multiple people have claimed that there is audible noise/hiss in their setup with their speakers....
In specification terms, the XLS series all have Signal/Noise ratios of over 100db - noise should not be an issue (SHOULD)
Reading through some threads that involved substantial experimentation - the noise issues in a number of cases, were eliminated, when mismatches between pre and power amps were resolved. - Basically if the preamp output is at too low a level, and you try to compensate by increasing gain on the power amp, you can get hiss.
Keeping in mind that the first generation XLS series had fixed input levels - with 1.4V (RMS) being the required level for rated power output. (the 2nd generation has switchable input level, allowing it to be switched to the consumer 1V RMS standard).
So if your pre was outputting only 1V, the end user was turning things up to get the desired volume, and amplifying pre-amp noise in the process... it wasn't in fact power amp noise.
This is a key issue in the use of many pro/pa amps in a consumer environment - consumer kit, by default, is 1V output levels, pro/pa by default is 1.4V.
The mismatch between the two can and does result in hiss....
So a key thing to investigate before jumping into a pro/pa amp, is investigating how well it will match with your available and intended pre-outs.
In my own use, the components I was using to provide pre-outs (AVR's) were formally specified as 1V output - but talking to the techs from the manufacturer, have actual capabilities of 2V.... when actually measured to clipping, my current AVR showed it could go up to 3.5V.
This means I have had no difficulties with matching pre to power - and have experienced no Hiss related issues.
My experience is consistent with the formal specifications for the XLS2500... 105db SN ... there should be no audible hiss!!
For people to better understand why I find the Crown XLS with its high current / low impedance speaker capabilities, valuable, is demonstrated, by these graphs showing the load and output of what I would consider a high quality traditional power amp, the Quad 606:
At 8 ohm it gets a very reasonable 135W (and a bit) ....
Within its current capacity, as the impedance drops to 5 ohm, we can see that almost ideal amp, ramping of power 5 ohm = 185W
At 4 ohm it has reached its power supply limit... and already started to fall back a bit as a result 180W@4ohm
Which just drops further as the impedance continues to fall with only circa 90W available at 2 ohm
P.S. it is worth considering these also in Voltage terms, as the loudness is directly equated to V.... 90W@2ohm is around 38V, and 38V @ 8ohm is 22W ... so in rough terms, using a Quad 606 ... once you get beyond 22W which is circa 98db in my setup - you hit limitations, and sound quality starts to deteriorate.
The Quad 606 sounded very good in my setup... The Crown sounds better - not massively so, but better (could I differentiate in a proper double blind test, probably not!). - I usually listen at 75db at MLP, and 98db gives me more than 20db headroom... it all makes sense...
My AVR driving the same speakers sounded terrible... and it was clear that even at the base 75db it was hitting some constraints - the Crowns fixed it immediately...
This is a pretty typical profile for a high quality audiophile power amp in the market - the power supply is the main limitation, and if your speaker impedance is below 4 ohm, you start to hit power amp constraints.
Every amp manufacturer should be publishing this kind of graph for their power amps, then we would not be left floundering in the dark, wondering why our 3 ohm speakers sound like rubbish with otherwise excellent amps!
Another warning though - even looking at the Crown professional range - the XLS series stand out, as having power supplies designed to really get the most out of the amp at low impedances - this is not the case for many of their other series, and especially their multichannel amps - where the power output tends to flatline after 4ohm or drop.
So yes - I am a big fan - the sound quality has been excellent, and the sound in my setup has been substantially improved by using them (even though I never use their power capability, and they merely cruise along at max 3W !!)
Could I achieve the same with a lower powered amp - yes most likely I could.... at a guess, and amp that was specified at 120W@8ohm, and at least 300W@2ohm would probably do the job.
Could I get such an amp (stereo) for US$400 ? - I haven't seen anything out there that could achieve that value equation (keeping in mind I paid US$250 for each XLS2500) - can I achieve this kind of performance for US$2000 to US$3000 - yes I can... but will it do better than what the XLS2500 is currently doing? While costing me 10x as much?
hmmmm
I have not talked about my experiments with Bridging and BiAmping, etc... with my speakers and my setup, these did not result in audible/noticeable improvements, and I reverted to simple, old, easy to cable and set up, standard setup - if I were more power constrained, it is possible that biamping could have provided some benefits... but with 400W+ on tap, there was no gain to be found there in my case. (and part of that being the fact that I am not a fan of the Harman target curve with +10db bass.... my preference is for a leaner, closer to flat Room EQ setup)
I read many reviews when the Crown XLS became a bit of a "cause celebre" in the Audiophile world, circa 10 years ago when Andrew Robinson replaced audiophile amps in his home theatre setup with a batch of XLS power amps, and then raved about their sound quality.
This triggered a bunch of people trying them out, with feedback of various types (yes ranging from - "absolute cr@p" to "Wow, Fantastic!" )
At the time a used XLS2500 could be picked up for US$250... , and I picked up 2 of them to try out for Biamping, and Bridging as well as straight stereo use
So about the XLS2500...
Power... although very high, the power is measured professional style as a 1kHz signal continuous, rather than 20-20khz... so you can discount the official figures by 20% to be safe...
440W @ 8ohm (Conservative 350W)
775W @ 4ohm (Conservative 620W)
1200 W @2ohm (Conservative 960W)
They can be bridged and get close to 2500W (hence the model name I believe) into 1 ohm
So here you have a very economical, (downright cheap! at the time...) power amp, capable of, in domestic terms, limitless power, and possibly more importantly, effectively limitless current (1000W @ 2ohm !!!)
Worthy of note: - it is a Class D design, and headroom above and beyond the rated spec is probably limited... so, unlike Class AB amps, you can't assume peak (time limited) headroom above and beyond the base spec.
How does this matter - well quite a few of us, have speakers which have complex and difficult impedance curves, in some cases dropping down to 1 ohm (certain Electrostatic speakers eg: ML) - and in many cases dropping below 3 ohm - particularly for the bass, where serious power is required, in addition to substantial current to handle the low impedance.
Additionally - the built in DSP with flexible crossovers, low pass and high pass filters allows for very easy biamping, driving of subwoofers, etc...
So those are the positives... (and applicable to quite a few pro amps)- what are the negatives?
First thing many audiophiles point to... it has a Fan.
Yes it does. and whether the Fan is audible or not, may be associated with multiple parameters - first being the noise floor in the listening room, second being how hard it is being driven, and whether it is "warming up".
Given it's HUGE power reserves, it is very very rare, that in any domestic situation, a set of these amps will go anywhere beyond idling.
This means that under 99% of consumer use circumstances - these will barely get warm, never hot - and the fans will either not turn on, or be barely ticking over.
My own experience: - with 88d SPL/wm - the signal LED (-20db from rated) - barely lights up on peaks at normal listening - that implies a touch over 3W continuous.... on Movie effects peaks - it may get to the -10db LED - which amounts to circa 50W... and that is when it is definitely too loud, and needs to be turned down... - so the amps are really only ever idling... and so are the Fans.
I have never heard the fans. (note: my listening area is also the family area, and base noise levels are not fantastic, even at the best of times, so Fan noise may be covered up)
Moving on, multiple people have claimed that there is audible noise/hiss in their setup with their speakers....
In specification terms, the XLS series all have Signal/Noise ratios of over 100db - noise should not be an issue (SHOULD)
Reading through some threads that involved substantial experimentation - the noise issues in a number of cases, were eliminated, when mismatches between pre and power amps were resolved. - Basically if the preamp output is at too low a level, and you try to compensate by increasing gain on the power amp, you can get hiss.
Keeping in mind that the first generation XLS series had fixed input levels - with 1.4V (RMS) being the required level for rated power output. (the 2nd generation has switchable input level, allowing it to be switched to the consumer 1V RMS standard).
So if your pre was outputting only 1V, the end user was turning things up to get the desired volume, and amplifying pre-amp noise in the process... it wasn't in fact power amp noise.
This is a key issue in the use of many pro/pa amps in a consumer environment - consumer kit, by default, is 1V output levels, pro/pa by default is 1.4V.
The mismatch between the two can and does result in hiss....
So a key thing to investigate before jumping into a pro/pa amp, is investigating how well it will match with your available and intended pre-outs.
In my own use, the components I was using to provide pre-outs (AVR's) were formally specified as 1V output - but talking to the techs from the manufacturer, have actual capabilities of 2V.... when actually measured to clipping, my current AVR showed it could go up to 3.5V.
This means I have had no difficulties with matching pre to power - and have experienced no Hiss related issues.
My experience is consistent with the formal specifications for the XLS2500... 105db SN ... there should be no audible hiss!!
For people to better understand why I find the Crown XLS with its high current / low impedance speaker capabilities, valuable, is demonstrated, by these graphs showing the load and output of what I would consider a high quality traditional power amp, the Quad 606:
At 8 ohm it gets a very reasonable 135W (and a bit) ....
Within its current capacity, as the impedance drops to 5 ohm, we can see that almost ideal amp, ramping of power 5 ohm = 185W
At 4 ohm it has reached its power supply limit... and already started to fall back a bit as a result 180W@4ohm
Which just drops further as the impedance continues to fall with only circa 90W available at 2 ohm
P.S. it is worth considering these also in Voltage terms, as the loudness is directly equated to V.... 90W@2ohm is around 38V, and 38V @ 8ohm is 22W ... so in rough terms, using a Quad 606 ... once you get beyond 22W which is circa 98db in my setup - you hit limitations, and sound quality starts to deteriorate.
The Quad 606 sounded very good in my setup... The Crown sounds better - not massively so, but better (could I differentiate in a proper double blind test, probably not!). - I usually listen at 75db at MLP, and 98db gives me more than 20db headroom... it all makes sense...
My AVR driving the same speakers sounded terrible... and it was clear that even at the base 75db it was hitting some constraints - the Crowns fixed it immediately...
This is a pretty typical profile for a high quality audiophile power amp in the market - the power supply is the main limitation, and if your speaker impedance is below 4 ohm, you start to hit power amp constraints.
Every amp manufacturer should be publishing this kind of graph for their power amps, then we would not be left floundering in the dark, wondering why our 3 ohm speakers sound like rubbish with otherwise excellent amps!
Another warning though - even looking at the Crown professional range - the XLS series stand out, as having power supplies designed to really get the most out of the amp at low impedances - this is not the case for many of their other series, and especially their multichannel amps - where the power output tends to flatline after 4ohm or drop.
So yes - I am a big fan - the sound quality has been excellent, and the sound in my setup has been substantially improved by using them (even though I never use their power capability, and they merely cruise along at max 3W !!)
Could I achieve the same with a lower powered amp - yes most likely I could.... at a guess, and amp that was specified at 120W@8ohm, and at least 300W@2ohm would probably do the job.
Could I get such an amp (stereo) for US$400 ? - I haven't seen anything out there that could achieve that value equation (keeping in mind I paid US$250 for each XLS2500) - can I achieve this kind of performance for US$2000 to US$3000 - yes I can... but will it do better than what the XLS2500 is currently doing? While costing me 10x as much?
hmmmm
I have not talked about my experiments with Bridging and BiAmping, etc... with my speakers and my setup, these did not result in audible/noticeable improvements, and I reverted to simple, old, easy to cable and set up, standard setup - if I were more power constrained, it is possible that biamping could have provided some benefits... but with 400W+ on tap, there was no gain to be found there in my case. (and part of that being the fact that I am not a fan of the Harman target curve with +10db bass.... my preference is for a leaner, closer to flat Room EQ setup)
Alice of Old Vincennes
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Cheaper and reliable. Cannot scam commercial customers. Reviews on this site repeatedly reveal overpriced junk targeted to home audio. If fan noise so obtrusive, where should I place computer? Basement, garage or treehouse?
Very interested in your limiter for my passive sub. How do you implement it, via DSP as a plugin? I currently use a multi band compressor plugin but have to manually activate it when I'm pushing high SPL and it would be nice to have a somewhat automated solution.
On topic - I've used several Crown amps over the years for sub duty and fan noise has always been why they don't last long in my set up. Currently looking to replace my XLi800 for the same reason. I need 4-500 cheap watts!
OP
- Thread Starter
- #118
Which particular models, tho? I've used my DriveCore XLS without anything audible in even close quarters as far as fan noise goes....
At a set price point, (yes value is part of the equation!), pro/pa amps often provide substantially more power and current.
This is fundamentally to do with mass market, economies of scale, etc...
Why is an AVR often the best value integrated amp / preamp ... because of economies of scale
Is it more suited for home use.... well if you remove the value for money part of the equation, probably not! If you include value for money as one of the key factors in suitability for the home - then yes, frequently a pro/pa amplifier is indeed more suitable than an equivalent consumer model.
Alice of Old Vincennes
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Brilliant analysis. Mismatch explains hiss. Anthem AVRs preouts exceed 2VMRS.
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