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looking for the PROPER POWER AMP

#63
I would ask @@BbbyBld about it. I am sure they have done a number of tests on the CA and ProLite amps.
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The input sensitivity is selectable on the CA-9...if I remember correctly, there is a jumper inside that you move (similar to the config jumper on the back of a hard drive). The input sensitivity can be configured to be about the same as a Prolite.

The difference between a CA-9 and pretty much any other pro audio power amp that I can think of is that the feedback loop is tuned in such a way as to create a more resonant low frequency response similar to what many guitar/bass amp designers do to enhance low end. The CA-9 is the preferred choice of many sound companies for driving subwoofers for that reason. Some might say the CA-9 has an unfair advantage in A/B listening tests. This type of low end enhancement is usually better for lower powered amps because it's a way to raise the low freq SPL without eating up headroom. When you are talking about the 2KW and above class of power amps, I'd bet you could pretty much get the same sound with EQ, especially if you know the resonant frequency of your cab.
 
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#64
BbbyBld said:
...The difference between a CA-9 and pretty much any other pro audio power amp that I can think of is that the feedback loop is tuned in such a way as to create a more resonant low frequency response...
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Is the same also true of the CA6 or others in the CA series? Thanks!
 
#66
BbbyBld said:
The input sensitivity is selectable on the CA-9...if I remember correctly, there is a jumper inside that you move (similar to the config jumper on the back of a hard drive). The input sensitivity can be configured to be about the same as a Prolite.

The difference between a CA-9 and pretty much any other pro audio power amp that I can think of is that the feedback loop is tuned in such a way as to create a more resonant low frequency response similar to what many guitar/bass amp designers do to enhance low end. The CA-9 is the preferred choice of many sound companies for driving subwoofers for that reason. Some might say the CA-9 has an unfair advantage in A/B listening tests. This type of low end enhancement is usually better for lower powered amps because it's a way to raise the low freq SPL without eating up headroom. When you are talking about the 2KW and above class of power amps, I'd bet you could pretty much get the same sound with EQ, especially if you know the resonant frequency of your cab.
Click to expand...
According to a very quick read of the CA* manual, it seems like the input sensitivity jumper is not a user changeable thing. Has this changed?
 
#67
According to a very quick read of the CA* manual, it seems like the input sensitivity jumper is not a user changeable thing. Has this changed?
Click to expand...

They have to put that in there because you have to open up the chassis to do it...you can't tell customers to pop the top on electronics gear (with high voltage inside) and go poking around.
 
#68
Goldburn94 said:
The Peavey Max preamp. Maybe I miss understood what @BurningSkies was walking about
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Input sensitivity is important because some bass preamps don't output the strength of signal that some power amps like to see at the input. So, if you've got an amp that wants 1.4v at the input and your preamp can't come close to that, you usually end up with an amp that's both not as loud as you expect but also is perceived as sounding anemic in comparison...because generally the ear compares louder things more favorably than less-loud things (probably the place to review the Munson Hearing Curve).

Many of us believe that a good power amp is one that is transparent. AKA what goes in the front comes out the back but louder. The CA9 has some additional mojo and therefore is doing some tone-shaping in the deep lows...which explains why people seem to favor it in bass applications. I've never had trouble EQing what I want from my sound without that.
 
#69
RoadRanger said:
Any of the DSP ones have an adjustable HPF AFAIK.
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Yes. But the lowest freq on the Crown XLS is 50Hz Linkwitz-Riley, which I think might be a tad too high for bass guitar. The Peavey/Crest DSP seems like it might go lower, but it's difficult to wade through their documentation...
 
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#70
Input sensitivity is important because some bass preamps don't output the strength of signal that some power amps like to see at the input. So, if you've got an amp that wants 1.4v at the input and your preamp can't come close to that, you usually end up with an amp that's both not as loud as you expect but also is perceived as sounding anemic in comparison...because generally the ear compares louder things more favorably than less-loud things (probably the place to review the Munson Hearing Curve).
Click to expand...

Besides that, I personally avoid power amps with low input sensitivity because it's often a way to sweep issues under the rug and make the specs page look more impressive. Why would they make a power amp that's hard to drive to full power? Hmmm... Why is the signal to noise ratio so impressive? Etc.
 
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#72
BbbyBld said:
Besides that, I personally avoid power amps with low input sensitivity because it's often a way to sweep issues under the rug and make the specs page look more impressive. Why would they make a power amp that's hard to drive to full power? Hmmm... Why is the signal to noise ratio so impressive? Etc.
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Actually, I like the XLS Drivecore series for just this reason. The sensitivity is 1.4 which is, in many regards, the standard for line level. I can mate mine with a mixer and it requires little or no attenuation to establish nominal gain structure....almost foolproof in that respect. OTOH, a QSC RMX 1450, for example, requires that the attenuators be rolled back to 37% (10:30) to do the same. Yes, I can drive them to full power or, more importantly, the upper margins where the limiters kick in. What's more important is the linearity of response between the two devices...and that's the purpose of setting gain structure...and that results in improved signal/noise ratio.

Riis
 
#73
Like Chef, I also used a QSC PLX for quite some time. Went away from the rack for a while. Rebuilt it a year ago using a Carvin DCM 2000L. Light as a feather and kicks like a mule. Pretty inexpensive. Great piece of gear for me.

All this stuff about some 60 pound heavy iron hits harder doesn't compute for me. The Carvin already gets too loud for a pretty loud mix. Maybe at ear bleed volumes you might be able to sense a difference; but, I'm not going there. Ever.
 
#74
BbbyBld said:
Only CA-9.
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Bizarre and very enlightening. When I tested a CA6 against a PLX2402 they sounded the same (when gain matched). All the CA9 owners were swearing there was a difference but I assumed CA6 and CA9 would sound identical. I always prefer a "bass amp" tone to a PA amp tone. Maybe I should try a CA9 ... Although im very happy with my db751 and wt1250.
 
#76
How many people that say there is no difference in tone actually directly a/b a lead sled and a class d amp, under strenuous conditions? There isn't a night a day difference; If I had to try the two amps on two separate days I may have overlooked the differences. But they were right there at rehearsal, both running racked right on top of each other, and I went back and forth between them probably half a dozen times that night.

The heavy amp stayed.
 
#77
JimiLL said:
How many people that say there is no difference in tone actually directly a/b a lead sled and a class d amp, under strenuous conditions? There isn't a night a day difference; If I had to try the two amps on two separate days I may have overlooked the differences. But they were right there at rehearsal, both running racked right on top of each other, and I went back and forth between them probably half a dozen times that night.

The heavy amp stayed.
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And I think I should clear up. ... No amp was louder than the other, they just held their composure differently when being pushed up to the point of clipping
 
#78
BurningSkies said:
The OP isn't really pushing a whole lot of firepower. There are piles of decent player-grade power amps out there that can serve up 500w per cab. Probably more important to make sure the input sensitivity matches the preamp he's using to make sure that the amp is being appropriately fed. While we know that shouldn't be an issue, it often is. I did a side by side with a CA9 and my IPR (a good friend got a used CA9 the same time I got my IPR) and the end opinion was they both sounded good but the IPR was lighter and easier to carry.
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Isn't this kind of sidestepping the while point? No one ever said one or the other amp sounded bad, any decent amp bought today isn't going to sound less than "good", but is there a perceived difference?
 
#79
BbbyBld said:
The input sensitivity is selectable on the CA-9...if I remember correctly, there is a jumper inside that you move (similar to the config jumper on the back of a hard drive). The input sensitivity can be configured to be about the same as a Prolite.

The difference between a CA-9 and pretty much any other pro audio power amp that I can think of is that the feedback loop is tuned in such a way as to create a more resonant low frequency response similar to what many guitar/bass amp designers do to enhance low end. The CA-9 is the preferred choice of many sound companies for driving subwoofers for that reason. Some might say the CA-9 has an unfair advantage in A/B listening tests. This type of low end enhancement is usually better for lower powered amps because it's a way to raise the low freq SPL without eating up headroom. When you are talking about the 2KW and above class of power amps, I'd bet you could pretty much get the same sound with EQ, especially if you know the resonant frequency of your cab.
Click to expand...
Now you have me interested in seeing a response chart of the CA-9 compared to an IPR2 3000.:D

Also a Power-Lite 3.0, Pro 7200, and CPX-2600 for good measure. ;)
 
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