Class D Questions

S

set theorist

Inspired
Still attempting to replace my 60lb Crest CA-6.

I notice a lot of people praising the QSC K-12, 10, 8 powered speakers. I've also seen a lot of posts (including my own) deriding class D amplification. Are the QSC's better than your average class D amps? Is there any class D out there that is better?

On a visit to Guitar Center, a surprisingly frank pro audio salesman told me that there is nothing, including the QSC's and the new Crowns, that will satisfy me as much as my Crest. He said it had something to do with the power switching transformers used in class D.

What do you guys think? Have K-12 owners ever compared their rigs versus a high end amp like the CA-6?

Thanks - Steve
 
What I've read about Class D amplification is that it does a good job with low frequencies but that it's not so good with high frequencies.
My experience, thus far, with Class D amps (Acoustic Image Clarus 2R, QSC K10 & K12) bears this out.

The Clarus 2R's preamp was made with a treble control that was not very typical of a guitar amp. But even when I used its power amp with various other preamps through speakers that I know well the top-end was never quite right.

I rented a K10 for a week once and I also rented a K12 for a week, and I found the top-end to be quite brittle and unnatural sounding.
Now part of the problem for me is that I have a hard time psychologically playing guitar through 2-way systems, where the top-end is coming out of a different speaker than the bottom-end. That's why I've been looking into trying out some coaxial FRFR designs, hoping I might dig it more.
But I also A/B'd the K10 with a Yorkville E10P, which is not a Class D design, and the top-end was much better, IMO, on the E10P. Too bad the rest of the tone coming out of the E10P was so unappealing.

So, personally speaking, I'm still wary of Class D power.

Class D's main attraction is that, pound-per-watt, Class D amps are *really* lightweight.
For guitar amplification the area between 10k and 20k isn't all that important. So it's not inconceivable that sometime in the near future somebody might come out with a Class D design that stays sweet up to 10k and it might be perfect for guitar amplification and a great companion for the Axe. If they're out there now, I just haven't heard it.
 
set theorist said:
On a visit to Guitar Center, a surprisingly frank pro audio salesman told me that there is nothing, including the QSC's and the new Crowns, that will satisfy me as much as my Crest.
Click to expand...

wow,that is surprising!the frank GC salesman part.he probably won't be there much longer. :shock:

i have heard nothing but good things about Crest amps.i wanted one myself,but it would have put me over budget. ;)
 
joegold said:
What I've read about Class D amplification is that it does a good job with low frequencies but that it's not so good with high frequencies.
My experience, thus far, with Class D amps (Acoustic Image Clarus 2R, QSC K10 & K12) bears this out.

The Clarus 2R's preamp was made with a treble control that was not very typical of a guitar amp. But even when I used its power amp with various other preamps through speakers that I know well the top-end was never quite right.

I rented a K10 for a week once and I also rented a K12 for a week, and I found the top-end to be quite brittle and unnatural sounding.
Now part of the problem for me is that I have a hard time psychologically playing guitar through 2-way systems, where the top-end is coming out of a different speaker than the bottom-end. That's why I've been looking into trying out some coaxial FRFR designs, hoping I might dig it more.
But I also A/B'd the K10 with a Yorkville E10P, which is not a Class D design, and the top-end was much better, IMO, on the E10P. Too bad the rest of the tone coming out of the E10P was so unappealing.

So, personally speaking, I'm still wary of Class D power.

Class D's main attraction is that, pound-per-watt, Class D amps are *really* lightweight.
For guitar amplification the area between 10k and 20k isn't all that important. So it's not inconceivable that sometime in the near future somebody might come out with a Class D design that stays sweet up to 10k and it might be perfect for guitar amplification and a great companion for the Axe. If they're out there now, I just haven't heard it.
Click to expand...

Have you had a chance to play through a FBT Verve 12mA yet...? I really like my 12M's / SLA-2 combo and the Raidian Micro wedge I have been playing through for quite a wile. Both are very musical with respect to the highs.
 
Sixstring said:
Have you had a chance to play through a FBT Verve 12mA yet...?
Click to expand...

Not yet. But they do not use Class D power amps.

From their web site:
"The Bi amplified Verve 12ma powered monitor/speaker features a 300w RMS Class G low frequency amp, and a
100w RMS Class G high frequency amp, both with switch mode power supplies."

Might be one reason why people like their sound so much.
 
I am going through the same dilemma. I want something relatively light, but with around 600 watts a side into 8 ohms. I am also a bit weary of class D amps. They are probably good for power but maybe not so much for the mids and highs, which is all important to the guitar. I suppose a switch mode power supply with a traditional output section is going to be a good compromise. Lighter and still would sound pretty natural.
 
Penge said:
I am going through the same dilemma. I want something relatively light, but with around 600 watts a side into 8 ohms. I am also a bit weary of class D amps. They are probably good for power but maybe not so much for the mids and highs, which is all important to the guitar. I suppose a switch mode power supply with a traditional output section is going to be a good compromise. Lighter and still would sound pretty natural.
Click to expand...

Same here. I have a QSC HPR112 and I really like it but it is heavy. I was thinking of getting a K10 or a K12 but now I just don't know. Maybe I'll just hold off a while and keep reading :?
 
Jay Mitchell said:
set theorist":15efvhmq]Here's a link: [url="http://www.crestaudio.com/products/browse.cfm/action/detail/item/116224/number/CFA-CA6-AB/cat/319/CA%206.cfm said:
http://www.crestaudio.com/products/brow ... CA%206.cfm[/url]

Its 400 Watts at 8 ohms and there is no affiliation with Peavey.
Click to expand...
Except that Peavey has owned Crest since ca. 1999, and every piece of Crest gear is manufactured in Peavey facilities....[/quote:15efvhmq]


Interesting...and yet, oh so sarcastic.
Click to expand...
 
jzgtrguy said:
Penge said:
I am going through the same dilemma. I want something relatively light, but with around 600 watts a side into 8 ohms. I am also a bit weary of class D amps. They are probably good for power but maybe not so much for the mids and highs, which is all important to the guitar. I suppose a switch mode power supply with a traditional output section is going to be a good compromise. Lighter and still would sound pretty natural.
Click to expand...

Same here. I have a QSC HPR112 and I really like it but it is heavy. I was thinking of getting a K10 or a K12 but now I just don't know. Maybe I'll just hold off a while and keep reading :?
Click to expand...

Don't let my comments here sway your decision.
Most folks who have tried the K10 and/or the K12 seem to like them *a lot*.
Try one yourself.
 
I was checking out the "post your rig" thread in the lounge and there seems to be a lot of QSC K series users...doesn't anyone care to defend them? I was watching some youtube videos of the Axe and I was hearing some great tones I'm just not achieving. Now I'm starting to think my speakers (Carvin 832s) may be part of the problem. That's what's so attractive about the powered speakers. I can get a lighter amp and new speakers in one shot.

I guess the Atomic stuff is really supposed to be the best fit for the Axe; but it seems low powered for live applications.
 
joegold said:
jzgtrguy said:
Penge said:
I am going through the same dilemma. I want something relatively light, but with around 600 watts a side into 8 ohms. I am also a bit weary of class D amps. They are probably good for power but maybe not so much for the mids and highs, which is all important to the guitar. I suppose a switch mode power supply with a traditional output section is going to be a good compromise. Lighter and still would sound pretty natural.
Click to expand...

Same here. I have a QSC HPR112 and I really like it but it is heavy. I was thinking of getting a K10 or a K12 but now I just don't know. Maybe I'll just hold off a while and keep reading :?
Click to expand...

Don't let my comments here sway your decision.
Most folks who have tried the K10 and/or the K12 seem to like them *a lot*.
Try one yourself.
Click to expand...

I'm curious Joe. What do you use?
 
I play my Axe through an ART SLA1 into 1 (bridged) or 2 (unbridged stereo) open back cabs with EVM-12Ls.

I've been experimenting with FRFR speakers but haven't found anything that sounds as good or better than the rig described above, yet.
 
I think I may give the K12 a try. I respect your opinion, Joe; but from what i am reading, high gain players are pretty happy with their K series stuff. I see from your page that your music is perhaps a bit more precise. Do you perform in any high gain styles? When you did audition the K series stuff, did you attempt any high gain settings.

I'm thinking style choice probably has a strong on what equipment is most appropriate. Do you agree?
 
set theorist said:
I think I may give the K12 a try. I respect your opinion, Joe; but from what i am reading, high gain players are pretty happy with their K series stuff. I see from your page that your music is perhaps a bit more precise. Do you perform in any high gain styles? When you did audition the K series stuff, did you attempt any high gain settings.

I'm thinking style choice probably has a strong on what equipment is most appropriate. Do you agree?
Click to expand...

I play hi-gain tones ala classic rock somewhat often in my work.
But not metal.

Most of my feelings about the unsatisfactory top-end I'm hearing from Class D amps and from 2-way FRFR systems comes from the way I've been able to get the clean tones to sound through these systems.
It just ain't right.
I like a lot of presence on my pop/R&B/rock based clean tones.
On my hi-gain tones I typically roll the top-end off quite a bit more. So I usually don't notice the hi-end problems of these systems as much when I'm playing a hi-gain sound.
 
set theorist said:
Interesting...and yet, oh so sarcastic.
Click to expand...
No sarcasm whatever. When you make a statement that is the perfect opposite of reality - one which can easily be checked by, say, Googling "Peavey Crest" - you shouldn't be particularly taken aback when correct information is provided.
 
Everyone here has actually done a comparison of Class A/B vs. Class D amps - one which eliminates every variable but the power amp - raise your hand.

Those of you who have compared different powered speakers, some with Class A/B amps (or variants thereof) and others with Class D amps need to realize that there is no possible way to generalize from such uncontrolled comparisons to the overall sonic properties of amplifier classes.

By far the greatest contributor to high-frequency unpleasantness in music-store FR speakers is the HF driver, followed closely by the HF horn and the crossover design. Many popular FR speakers produce nasty-sounding (to me, at least) HF sounds, regardless of the amp that is used to drive them.

Bottom line: while there are certainly disadvantages to some implementations of Class D output stages, there is no way to generalize to the entire class based on a handful of subjective comparisons in which multiple variables were changed at the same time.
 
Jay Mitchell said:
Everyone here has actually done a comparison of Class A/B vs. Class D amps - one which eliminates every variable but the power amp - raise your hand.
Click to expand...

I raise mine. Crest CA6 vs Peavey IPR 1600 through Carvin 832 PA speakers. They may be the same company; but obviously not all of their products are made the same or are of the same quality.

I understand the reason for the variance; but it is very disconcerting when you are looking for the best set up that 10 people seemd to have 10 different opinions...especially when it would cost 100s to make the comparisons for oneself.

Thus far, after reading hundreds of posts, there seems to be two salient opinions: practically nothing Behringer or JBL make is any good and the Art SLA is more liked than not. Everything else seems to be no better than 50/50.
 
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