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Need Power amplifier Recomendations 1000.00 or less 500 watt minimum @4ohm.

andreasmaaan

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Im afraid that claim cant be correct. The filter only filters out of band signals. Intermodulation created in the amplifier circuit in band would not be filtered and show up.

The filter is there to stop problems (like IM) with the input stage of the measurement system, which would be spurious.

Lol, of course you're correct. Momentary brain absence on my part. Carry on then...
 

Wombat

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Given the fact that bats have excellent HF detection and the association of bats with vampires, audiophiles who claim to hear above 22kHz make me nervous.
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Given the fact that bats have excellent HF detection and the association of bats with vampires, audiophiles who claim to hear above 22kHz make me nervous. View attachment 15962

Why then do you have all these standards over 44-48 KHz, and why are even people on ASR recommending people to run things at 96 KHz and higher?
 

Wombat

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Why then do you have all these standards over 44-48 KHz, and why are even people on ASR recommending people to run things at 96 KHz and higher?

Beats me.
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Sal1950

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Why then do you have all these standards over 44-48 KHz, and why are even people on ASR recommending people to run things at 96 KHz and higher?
We've had no influence on the development or promotion of high data rates. That's been done by many others for decades now.
As far as "recommending", I know of only a couple members here that believe there is real audible value in better than redbook playback. But there are lots of solid reasons for recording at the higher data rates, that has been extensively discussed here and most all would support that.
 

Blumlein 88

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Why then do you have all these standards over 44-48 KHz, and why are even people on ASR recommending people to run things at 96 KHz and higher?
The same reason we have 20 megapixel cameras while most photos are viewed on 2 megapixel monitors?
 

garbulky

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Well I just tried a pair of ICE AS300 module monoblock amps (the Emotiva PA-1). I'm going to have to eat my preconceptions about class D. (Subjective impressions only no DBT) To my ears, they sound utterly fantastic. And they drove two pairs of large speakers that AB other amps had trouble with. At those prices ($300 per mono), you could easily get a stack of four monoblocks going for some serious power if you biamp. But I never had trouble with the volume - it got very loud quickly with just a pair.
 

Dana reed

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Well I just tried a pair of ICE AS300 module monoblock amps (the Emotiva PA-1). I'm going to have to eat my preconceptions about class D. (Subjective impressions only no DBT) To my ears, they sound utterly fantastic. And they drove two pairs of large speakers that AB other amps had trouble with. At those prices ($300 per mono), you could easily get a stack of four monoblocks going for some serious power if you biamp. But I never had trouble with the volume - it got very loud quickly with just a pair.
I concur with this as my AB amps had trouble running Magnepans to higher volume levels without going into protection, while the pair of Red Dragon M1000 mkII I have now are sounding great. These are also based on ICEPower modules.
 

VMAT4

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From my experience see if Class D Audio has an amp or kit that meets your needs. Here's a link: http://classdaudio.com .
 

derp1n

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Why then do you have all these standards over 44-48 KHz, and why are even people on ASR recommending people to run things at 96 KHz and higher?
ASR is an open forum. Not every post is correct, and not every poster's beliefs are aligned with ASR's raison d'être.
 

DrTebi

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Just my 2 cents... I have quickly given up on Class-D amps. Bought a Lab Gruppen IPD2400 to power my subwoofers. Supposedly a great amp (well, at least the marketing department seems to think so), but it was just disappointing. Nothing but noise problems. I basically had to maneuver my pre-amp and other devices around just to get a somewhat low noise floor. Sent it back and, with a bit of luck, got a vintage Accuphase P550 for almost the same price. Never had a problem with that beautiful beast... dead quiet, and easily drives a pair of open-baffle 18" woofers to levels until the wife complains :)

Sure, I was probably just unlucky and got a lemon of a class-D amp. But generally, I prefer to look for those top-of-the-line vintage amps from the "Golden Era" of HiFi, there are some great ones out there for very reasonable prices.
 

maty

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Some questions:

* Who needs 500 watts at 4 Ohms to play music in a house? Very BIG room?

* Class D, only modern off course. Which kind of music? Electronic, hip-hop and others usually bad recordings with voices with autotune (vade retro satana) or acoustics instruments recordings with high DR?

* Room size and speakers sensitivity?
 

andreasmaaan

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Just my 2 cents... I have quickly given up on Class-D amps. Bought a Lab Gruppen IPD2400 to power my subwoofers. Supposedly a great amp (well, at least the marketing department seems to think so), but it was just disappointing. Nothing but noise problems. I basically had to maneuver my pre-amp and other devices around just to get a somewhat low noise floor. Sent it back and, with a bit of luck, got a vintage Accuphase P550 for almost the same price. Never had a problem with that beautiful beast... dead quiet, and easily drives a pair of open-baffle 18" woofers to levels until the wife complains :)

Sure, I was probably just unlucky and got a lemon of a class-D amp. But generally, I prefer to look for those top-of-the-line vintage amps from the "Golden Era" of HiFi, there are some great ones out there for very reasonable prices.

Looking at the spec sheet for that amp, THD+N is listed as <0.1%, with no measurement conditions specified, i.e. it can be assumed that this is the best case scenario.

0.1% THD+N is pretty mediocre performance for an amp, especially one that pricey, and certainly high enough to be potentially audible.

Glad you're happy with the Accuphase :)
 

DonH56

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Re. power -- whilst I think most people have more power than they really need, a pair of Salon2's driven by 500 W each achieves about 108 dB in my fairly modest room (13' W x 17.5' L x 8.5' H). That would be intolerable to me sustained but well within the range of peaks movies and music may have. Oddly I often find myself at either extreme of the power argument; for most average systems there is more than enough power and I loathe the power amp craze, but a lot of higher-end'ish speakers combine low sensitivity and low'ish impedance requiring a goodly amount of power on tap to accurately reproduce dynamic peaks.

A lot of pro amps and some high-end consumer amps have fairly modest distortion specs. Move the rating a few percent in power either way and you can easily get huge swings in distortion as most rate right at the limit of clipping. Look at any review and notice how the distortion spikes up just past rated power. So 0.1% at 1200 W/ch is probably much lower at a mere 1000 W/ch, and that would be plenty enough for me.

Noise is an issue with many high-power pro amps in particular. They need higher gain to deliver all that power, and yet in a large venue SNR is not a huge factor since crowds are fairly loud and back from the speakers anyway. Several pro amp manufacturers have added gain to suit home systems but of course that exacerbates the noise problem.
 

svart-hvitt

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Re. power -- whilst I think most people have more power than they really need, a pair of Salon2's driven by 500 W each achieves about 108 dB in my fairly modest room (13' W x 17.5' L x 8.5' H). That would be intolerable to me sustained but well within the range of peaks movies and music may have. Oddly I often find myself at either extreme of the power argument; for most average systems there is more than enough power and I loathe the power amp craze, but a lot of higher-end'ish speakers combine low sensitivity and low'ish impedance requiring a goodly amount of power on tap to accurately reproduce dynamic peaks.

A lot of pro amps and some high-end consumer amps have fairly modest distortion specs. Move the rating a few percent in power either way and you can easily get huge swings in distortion as most rate right at the limit of clipping. Look at any review and notice how the distortion spikes up just past rated power. So 0.1% at 1200 W/ch is probably much lower at a mere 1000 W/ch, and that would be plenty enough for me.

Noise is an issue with many high-power pro amps in particular. They need higher gain to deliver all that power, and yet in a large venue SNR is not a huge factor since crowds are fairly loud and back from the speakers anyway. Several pro amp manufacturers have added gain to suit home systems but of course that exacerbates the noise problem.

I think what concerns people, is peak volume, this very short period where sound is 20-30 dB above base level?

And for film buffs, 120 dB capacity may be needed?
 

maty

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You are wrong.

Tell me the speakers yo have or the sensitivity and minimum impedance.
And the listening distance and we will see what the engineering technique/science says about it.
 

DrTebi

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Looking at the spec sheet for that amp, THD+N is listed as <0.1%, with no measurement conditions specified, i.e. it can be assumed that this is the best case scenario.

0.1% THD+N is pretty mediocre performance for an amp, especially one that pricey, and certainly high enough to be potentially audible.

Glad you're happy with the Accuphase :)
Yes, that THD+N sounds pretty bad. But I also have a very early Accuphase P-20, which in fact has the same THD+N (0.1%), and it doesn't make a sound no matter where I place it, what other device is on top etc.

I am no expert, but I believe the switching power supply may have been the culprit in my case. Or—as I already mentioned—I got unlucky and got a lemon. Who knows... maybe I should have done some measurements, but I am unfortunately not equipped to do so.
 

Johnb

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A pair of used Adcom GFA 555 II's running in bridged mode, rated at 600w into 8ohms continuous.
Designed by Nelson Pass.
Lots of them for sale on ebay.

hoohoo! That brings back memories. My first serious stereo, GFA 555 and JBL L100T Centuries, bought after starting my first serious job after college. I remember that both were "recommended" by Julian Hirsch, remember him? A gentleman of a reviewer. They knocked him for never trashing any component that he reviewed (and measured). But he was too nice. He never got crazy excited either. With Julian, you had to read between the lines. You could glean what he liked. Kind of like the analysis after every meeting of the Federal Reserve. Didn't know the Adcom was a Pass design.
 

DonH56

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You are wrong.

Tell me the speakers yo have or the sensitivity and minimum impedance.
And the listening distance and we will see what the engineering technique/science says about it.

Been wrong before, will again, not sure someone has so emphatically questioned my engineer/science background recently...

Speakers = Revel Salon2
Sensitivity = 84.6 dB/W/m -- I used 85 dB/W/m
Listening distance = about 8 feet
Min impedance 3.7 ohms per Revel; around 4 ohms through much of the bass region (see e.g. https://www.stereophile.com/content/revel-ultima-salon2-loudspeaker-measurements). The way I calculated I did not need impedance (not a direct variable in the equations).

I assumed a pair and anechoic response given that my room is very heavily damped. This is how I figured it (from memory, so could well be off):
  • 500 W = 27 dBW (power gain from amplifier)
  • Add 3 dB for a pair of speakers (power doubling from the extra speaker)
  • 8' = 2.44 m so subtract 7 dB for distance (6 dB for each doubling in distance)
  • Net SPL = 85 + 27 + 3 - 7 = 108 dB at the listening position
That agrees with a couple of online calculators I quickly checked. What part is wrong?
 
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