Crest CA9 or Stewart 2.1

[vision]

You EQ to make the overall bass and rig sound good, not the power amp.

But if you sound "good" with setup A without having to EQ, and with setup B you have to EQ to sound "good", and the only difference between the two setups is the power amp, logic would dictate that the power amps do not sound exactly the same.

 

[monkeyfinger]

We've been down this road sooo many times.

In my experience, the Crest Audio CA-9 is a far better power amp for bass than a QSC PLX. (I owned a PLX.) For the mids and highs in a PA system, I would not hesitate to use the QSC PLX.

 

[tombowlus]

In my experience, the Crest Audio CA-9 is a far better power amp for bass than a QSC PLX. (I owned a PLX.) For the mids and highs in a PA system, I would not hesitate to use the QSC PLX.

+1

 

[Vic]

You can drop one amp in after another, and the tone will be the same after you adjust for gain.

We'll just have to agree to disagree on this.

IMHO, If this were really true, that all pro power amps were literally identical in their sound reproduction under all circumstances, then there'd be only one amp manufacturer out there doing business, and it would be the one with the greatest power/cost ratio.

Maybe this all boils down to an audible difference in the way an amp behaves once you get preamps and speakers involved vs the reference test environment.

 

[Phat Ham]

IMHO, If this were really true, that all pro power amps were literally identical in their sound reproduction under all circumstances, then there'd be only one amp manufacturer out there doing business, and it would be the one with the greatest power/cost ratio.

Well there are other things like reliability, reputation, feature set, packaging, etc to account for.

 

[monkeyfinger]

Well there are other things like reliability, reputation, feature set, packaging, etc to account for.

Oh yeah, design too.

 

[Dr. PhunkyPants]

Poor, beseiged Bob. Sisyphus has nothing on you, man. I do respect your dogged defense of your product.

One of these days we'll be debating this same thread for the thousandth time and balloons will spill out of the ceiling....

 

[BuffaloBob4343]

One of these days we'll be debating this same thread for the thousandth time and balloons will spill out of the ceiling....

That is FUNNY!

Inherently, I believe what Bob is saying is true, basically because I am trained as an electrical engineer, although I haven't worked as one in 20 years. There may be some input conditioning (e.g. gain staging that needs to be done in certain circumstances) to make the comparison the same.

What I'm not sure about offhand is why that would need to be so. Is there something about the PLX input charactersitics that require input conditioning that is not required by other amps, and if so, is there an advantage that is realized by this?

I can understand that the PLX may need a signal from the preamp that is hotter (i.e. has more amplitude) to make all else equal, but why?

 

[jokerjkny]

my booty says CA9, but my back says world2.1

seriously, the ca9 could easily dislocate something if i'm not careful after a long gig. the 2.1 however is pretty darn nice, and was an option until i picked up a qsc 1804.

 

[dominic54321]

my booty says CA9, but my back says world2.1

+1

 

[avid]

One of these days we'll be debating this same thread for the thousandth time and balloons will spill out of the ceiling....

Why debate? I think this requires a GTG to test out power amps. Borrow one or make one of those machines that allows you to match amps with a random unknown amp. Invite some sound experts to make sure things are done correctly. Then answer this question for the TB crowd once and for all.

 

[Vic]

my booty says CA9, but my back says world2.1

+1

seriously, the ca9 could easily dislocate something if i'm not careful after a long gig. the 2.1 however is pretty darn nice, and was an option until i picked up a qsc 1804.

So you switched from the 2.1 to the 1804? Care to share what you liked better about the 1804?

 

[Kindness]

That is FUNNY!

Inherently, I believe what Bob is saying is true, basically because I am trained as an electrical engineer, although I haven't worked as one in 20 years. There may be some input conditioning (e.g. gain staging that needs to be done in certain circumstances) to make the comparison the same.

What I'm not sure about offhand is why that would need to be so. Is there something about the PLX input charactersitics that require input conditioning that is not required by other amps, and if so, is there an advantage that is realized by this?

I can understand that the PLX may need a signal from the preamp that is hotter (i.e. has more amplitude) to make all else equal, but why?

I believe Bob too, not only because I hold a degree in engineering, but because I have played the PLX 3002 and the CA9 in what I believe to be a gained matched scenario using the published voltage gains (86.5x vs. 40x!!!) of the amps and my trusty multimeter to test my preamp output voltage. I now own the PLX. Granted it wasn't double blind and there is no way to qualify myself as the right ears for the job, but it works for me in theory and in practice.

This constant debate reminds me of the people that commented how much fuller their Thunderfunks sounded with the limiter engaged, even when the limiter wasn't lighting up. It's because the gain increases when the limiter is engaged. The reality is it doesn't sound anything other than louder. Subtle differences in gain structure can really play tricks on our ears.

http://en.wikipedia.org/wiki/Fletcher-Munson_curves

When I was in school, one of my professors used to comment about how frustrating the world would become once we had enough engineering knowledge to understand how things worked, but had to tolerate everyone around us believing things were more magical than they are. I used to think he was a complete jerk to pass judgment on people with different educational backgrounds. Now I remember he always followed that comment with some thoughts about passing on our knowledge and teaching those around us what we can. For that I thank all of the contributers that spend their time trying to teach, whether it's Bob Lee, Jerrold Tiers, Psycho Bass Guy, etc.

 

[jokerjkny]

+1

So you switched from the 2.1 to the 1804? Care to share what you liked better about the 1804?

honestly,

i've never owned the 2.1, tho i've used it countless times at a local shop. again, great amp, but they were a touch spotty for my tastes with service on a World 250. and the 1804 does feel that much lighter weight than the 2.1, which is waaay overkill even for my Acme needs.

but when i saw biker4him had his 1804 in the emporium, i jumped on the opportunity, and its terrific! nicely punchy and quick feeling with plenty of power to spare w/ 600 watts @ 8ohms and 800 watts @ 4ohms per channel. which for me is roughly 1200 watts no matter how you slice it. just HUGE sounding w/ my Epifani UL112's. heck, w/ my Quest II preamp, i pretty much have a 4 rack UL902 that doesnt weigh that much more!

and while it does have a small fan like motor sound, its still relatively quiet for most PA apps. heck, i'm using it with my Ipod at this very moment to help break in a new pair of cabs i just got. and its stupid light. says 13 lbs. on the website, but WAAY lighter feeling. also, i dig the shorter depth which is great for fitting into my Aguilar rack bag. no more sticking out the back end like my old Peavey DPC, nor my Stewart World. and truth be told, i'm a sucker for silver panels.

admittedly, i was never ga-ga enough to pick up a PLX series amp, cause it always felt MUCH heavier than its reported 21 lbs., and at the time, my stewarts were plenty for my needs. but the PLX2 1804 is soo freakin' light and easy to use thx to a minimal backpanel with all connections i really need. and besides, a power amp should only come w/ speakons!

if anything, its my fav power amp at the moment. sure, it doesnt have the mule like kick of a CA9, but i definitely wont be cursing it for more punch when i'm onstage, nor when i'm loading out into the trailer afterwards.

and cmon, we're talkin' QSC + Bob Lee on TB = no worries.

the only niggle i have is the front panel which doesnt feel as rock solid as the earlier PLX series, nor the rubber knobs, which feel like they might break right off during one of those drunken gigs. but i guess its one of the ways they're trying to keep the weight down.

but again, these are frickin' niggles on an amp that deserves more praise than my moaning.

Link Removed

 

[jokerjkny]

lol,

sorry for the massive derail.

 

[jokerjkny]

Why debate? I think this requires a GTG to test out power amps. Borrow one or make one of those machines that allows you to match amps with a random unknown amp. Invite some sound experts to make sure things are done correctly. Then answer this question for the TB crowd once and for all.

omg,

i'd totally be down for something like that! then again, btwn myself and dave wilson, we'd only need the two of us.

or just one tombowlus!

 

[Vic]

When I was in school, one of my professors used to comment about how frustrating the world would become once we had enough engineering knowledge to understand how things worked, but had to tolerate everyone around us believing things were more magical than they are.

So everybody that thinks a QSC sounds different than a Crest is just ignorant and/or stupid? That there's literally no difference in behavior between a reference test environment, and one where other component combinations (preamps, speaker systems) are used?

...stunned...

I don't understand how somehow power amps are exempt from the basic rule that says the test environment plays a role in the test results, which is why we even have a "reference"... for consistency. If the test environment did not play a role, there would be no need for a reference, because perfect consistency would always be achieved no matter what was attached, which is the only way I think statements like these can be supported.

 

[seamonkey]

FWIW, I agree with Bob, although it probably doesn't help his cause.

Power amps all being sonicly equal, abx testing, null testing could prove it for humans, but nobody would believe it. Manufacturers will probably all start adding DSP's/signal processing to change the transparency and build a differentiating factor that makes them sound good in the store, but be able to switch to a practical curve in real use.

 

[el_Kabong]

So everybody that thinks a QSC sounds different than a Crest is just ignorant and/or stupid?

I have the greatest respect for Bob Lee, no way I'm qualified to argue with him. I can only say 900w of one side of a CA9 murders the alleged 1100w of a bridged wt800b, even at the 'same' volume. Like Joker says, the ca9 kicks like a mule. Surely so may similar experiences can't be written off or just put down to user ignorance? I wonder if blind tests based purely on hearing might give a different result to ones based on playing the amp, ie focusing on the feel and response as well as the sound.

 

[Dr. PhunkyPants]

I guess here's my main question....

Why doesn't QSC add a feature to the PLX series amps that allows the user to adjust the input voltage so that the user can tailor the power amp to the preamp the player happens to be using? Even a chicklet switch with two options would work, or a dip switch. The Eden Navigator has a DIP switch for adjusting it's output strength...

As someone who's tried over 20 preamps, I can appreciate how some sound great but do not give my Crest enough signal to get all the amp has to offer. The same is certainly true, if not moreso, for PLX amps, I would think.

I'm not an engineer (clearly). But wouldn't the $5 componentry to add this feature be worth the enhancement in the product line image that would ensue?

If it all comes down to gain matching and the reason PLX's fall short of the CA series with "the ignorant masses" is because it doesn't match gains, then I ask: "What is the solution, from a product design perspective?"