Power specs

[edwinhurwitz]

I'm finding it odd that manufacturers are going back to the trend of providing very vague power specs. Time was most specs were given at RMS levels from 20-20khz at certain distortion levels. Nowadays it looks like we're dealing with specs that have no bandwidth mentioned or if there is, it's at 1khz. Bandwidth specs are at 1 watt. It's really hard to tell what's going on with these amps.

Cases in point:
Peavey IPR series
Crown XTI series

[T-Bird]

Hi.

I don't find it odd at all, watts are what sells the amps (and cabs).

Especially true with the "budget" brands.

AFAIK/IME, truthful marketing has never existed outside the pro-audio circles anyway.

Regards
Sam

[edwinhurwitz]

Yeah, I know, but it seemed like there was a good trend the last time I looked into purchasing an amplifier. This feels like backsliding. Perhaps it's part and parcel of sending all the manufacturing to China with all the design decisions getting made on Wall St.

Still, my Xti4000 doesn't sound too shabby. I'm going to have to put up against my CA9 to see how it matches up head to head, but the decrease in weight makes it a lot easier to put up with some vagueness in numbers.

[seamonkey]

"RMS" is vague. "Continuous" is vague. There is just no consumer group policing musical instrument gear.

If you want to sell to consumers for home stereo gear the FTC is involved (in the US). You have to have an FTC rating. And you can believe one FTC rating from one manufacturer is comparable to another FTC rating from another.

FOH/Pro audio amps are going to have "EIA", "EIAJ" or "FTC" if they also sell to home audio markets. No FOH, or sound installation company is going to rely on vague specs.

Musical Instrument gear Consumers should demand ratings based on standards.

It's not going to happen otherwise.

[pickles]

It almost doesn't matter anymore. Getting a nice powerful amp at a reasonable price used to be hard, but now everybody makes a 500w micro (and they thump!), and you can just pick your poison between lead sled voodoo and lightweight price/performance on the pro audio side.

[dave2]

Originally Posted by edwinhurwitz

Yeah, I know, but it seemed like there was a good trend the last time I looked into purchasing an amplifier. This feels like backsliding. Perhaps it's part and parcel of sending all the manufacturing to China with all the design decisions getting made on Wall St.

Still, my Xti4000 doesn't sound too shabby. I'm going to have to put up against my CA9 to see how it matches up head to head, but the decrease in weight makes it a lot easier to put up with some vagueness in numbers.

I like my Crown XTi 4000. With my Demeter pre it pushes my 4 ohm Aguilar GS 410 very nicely.

@edwinhurwitz
Not to derail the thread but I have an XTi4000 and I would like to hear the results of your test of an CA9 vs. XTi4000. You can PM me if you would like.


Now back to our regularly scheduled programming.....

Dave

[chucko58]

Some amp makers (cough *CARVIN* cough) use deceptive ratings like "THD < 0.1% @ 90% rated power". To me this says the actual power rating is 90% of what's claimed.

The most useless specs are XXX watts @ 1 KHz at .XX% distortion. Mid-band power is easy. What does it do at the low end? That's where the power supply section makes all the difference.

I was looking at the Peavey IPR spec sheets the other day and thought they were pretty clear and honest, especially about the reduction in maximum power at high frequencies. (This is due to the output filter a Class D amp must have, without which it would become a radio transmitter.)

[greenboy]

I wouldn't consider that Carin rating deceptive, I'd look at the context first. It is after all a referenced spec. Is that for an instrument "amp"? I know I've used Carvin power amps in the same rack as QSC, Peavey, Crown, and they perform within the same parameters to the point that I can consider tham all commodities in most situations.

As far as "heads" things are altogether different and rating can be largely meaningless for a number of reasons, including baked in voicing, supplied AC issues, type of themral and limiting protection etc. I hate the things because you can't just pick a reputable brand and read a comprehensive spec that an engineer would suss what it all means ; }

Power amp specs from reputable companies tend to list output in several ways; at their worst they are usually a lot more thorough than instrument amp people at their best.

[projectMalamute]

Originally Posted by edwinhurwitz

I'm finding it odd that manufacturers are going back to the trend of providing very vague power specs. Time was most specs were given at RMS levels from 20-20khz at certain distortion levels. Nowadays it looks like we're dealing with specs that have no bandwidth mentioned or if there is, it's at 1khz. Bandwidth specs are at 1 watt. It's really hard to tell what's going on with these amps.

Cases in point:
Peavey IPR series
Crown XTI series

You have to look at the market those amps are being sold to. Both of those lines are entry level bar band/DJ amps. Not that they don't work and sound fine, but it is what it is. The amps being sold to professional contractors who can read a sheet, interpret the information, and spec a system accordingly come with much more detailed information. Look at a spec sheet for a Crown I-Tech or Macrotech amp, or a Crest (Peavey) 200 series amp.

[Bob Lee (QSC)]

Originally Posted by chucko58

Some amp makers (cough *CARVIN* cough) use deceptive ratings like "THD < 0.1% @ 90% rated power". To me this says the actual power rating is 90% of what's claimed.

I sure wouldn't interpret it that way; don't confuse THD specs and power ratings.

You don't do a THD spec at rated power because rated power is deliberately measured at the onset of clipping, where the sine wave is just starting to flatten out on the tips (as defined by the THD figure in the power spec).

The THD figure cited in a power spec is not a THD spec, and a THD spec is not a power spec.

A THD spec should describe the linearity of the amp circuitry. The power spec describes the limits of its linear operation.

[greenboy]

Originally Posted by projectMalamute

You have to look at the market those amps are being sold to. Both of those lines are entry level bar band/DJ amps. Not that they don't work and sound fine, but it is what it is. The amps being sold to professional contractors who can read a sheet, interpret the information, and spec a system accordingly come with much more detailed information. Look at a spec sheet for a Crown I-Tech or Macrotech amp, or a Crest (Peavey) 200 series amp.

I don' think you've interpreted what is going on. Entry level prices on new-gen units are actually ushering in some performance gains that are being utilized through various tiers. Big players have been interested in these units too. To make it sound all junior-league is a disservice.

[projectMalamute]

Originally Posted by greenboy

I don' think you've interpreted what is going on. Entry level prices on new-gen units are actually ushering in some performance gains that are being utilized through various tiers. Big players have been interested in these units too. To make it sound all junior-league is a disservice.

I happen to quite proudly spend my time in junior league circles. I can (and have, lots and lots of times) put on a show with whatever cobbled together nonsense you can scrape up, and it will probably sound a damn site better than a million dollar rig in a room meant for hockey games.

It doesn't change the fact that someone looking to power a Xyon line array is not shopping at Guitar Center. Most companies out there make stuff for different markets, and while the technology in a CE4000 is probably not all that different than that in an I-Tech, the expectations of the people purchasing them are. One of those expectations is documentation, another is reliability, another is support in the field and serviceability.

While you absolutely could power an arena show with a rack full of Crown XLS amps you will never see it. Totally different market, one that is willing to pay more money for things that will never make a difference to most of us.

[BassmanPaul]

Originally Posted by chucko58

Some amp makers (cough *CARVIN* cough) use deceptive ratings like "THD < 0.1% @ 90% rated power". To me this says the actual power rating is 90% of what's claimed.

Yet another case of Carvin bashing. I own several Carvin power amps from the DCM series. ALL of them meet or exceed their published power ratings.

[Calaverasgrande]

All I know is tubes rule!

[Growly Lytes]

They gotta be tested live.

[BurningSkies]

Originally Posted by greenboy

I wouldn't consider that Carin rating deceptive, I'd look at the context first. It is after all a referenced spec. Is that for an instrument "amp"? I know I've used Carvin power amps in the same rack as QSC, Peavey, Crown, and they perform within the same parameters to the point that I can consider tham all commodities in most situations.

As far as "heads" things are altogether different and rating can be largely meaningless for a number of reasons, including baked in voicing, supplied AC issues, type of themral and limiting protection etc. I hate the things because you can't just pick a reputable brand and read a comprehensive spec that an engineer would suss what it all means ; }

Power amp specs from reputable companies tend to list output in several ways; at their worst they are usually a lot more thorough than instrument amp people at their best.

Now, if I team up an amateur amp like a Peavey IPR series with a preamp like a Demeter or a Kern, which end of the snoot factor will it tip my rig towards? I mean, I don't want to show up at the hockey arena and be laughed at.

[BurningSkies]

Originally Posted by greenboy

You'll be turned into a piker DJ cum Karaoke star.

I can see myself, loosened tie askew, half a glass of cheap rye whiskey crooning an off key Dust In the Wind already...

DAMN YOU PEAVEY!!!!

[greenboy]

Buck up, man! - dare to be GREAT!

[BurningSkies]

Could go either way.

[Foz]

Piker Djcum Karaokester...

is my new stage name