[warnerwh]

After seeing the Carver which is rated at 300 wpc into 8 ohms only put out 200 I'm afraid I''m still confused as to how much power these amps put out into a real pair of speakers.  The maker claims the power must be measured with a filter yet nobody will be using this filter when using the amplifier.  Now do these digital amplifiers make their advertised power into real speakers or not? Engineer types please explain here, thanks.
 If they don't put out rated power then shouldn't they be rated at what they really do put out?  I'm completely aware that the difference in ouput from 200 to 300 watts is only 1.5 db but feel the ratings are at least misleading especially since the dynamic headroom was minus 3 to minus 4.5 db on top of the strange power ratings.

[Brian Cheney]

If an amplifier produces less than rated power it has negative dynamic headroom, for the ZR1600 that means minus 1.75 dB if it measures 200W at clipping instead of 300W.  The manufacturer instructs the tester to ignore conventional signs of clipping (oscillation, flattening of waveform peaks) and look at flattening of the residual waveform as an indication of clipping.  So, the power output of a switching amp is a matter of opinion.  I don't think it would be accurate to call the ZR1600 a 300W amp into 8 Ohms, but I can't tell you what we should call it.

[warnerwh]

Excuse my misunderstanding of the way you were checking dynamic headroom. I thought it was a short term power measurement somewhere in the neighborhood of a millisecond that was measured. Thanks for the clarification. Hopefully Kevin and the Carver Pro people can help us understand.

[eico1]

Since the digital amps have high order distortion components reaching above 20kHz, the filters will give better readings when measuring max power@some level of thd by reducing those frequencies. Supposedly you won't hear these componets.

As far as funny looking waveforms, I don't know!



steve

[KevinW]

Warner,
My amp is rated at its actual power output. I'm not interested in inflating specs of my amps.  The stereo amp does 250 watts RMS per channel into 4 or 8 ohms. The limiting power factor in my amp is the size of the power transformer.  I used a 500 VAC, which can supply 500 watts of continuous power. Instantaneous power is handled by the capacitor banks, which is 500/250 watts per channel into 4/8 ohms. The monoblock version will do 500 watts RMS into 4 ohms, because there is only one power module drawing current.

  You can get a very good estimate of the max continuous power output of any amp if you check the VAC of the transformer.  I didn't get a good look at the power transformer of the Carver, but perhaps Todd is willing to crack his amp open and check the ratings.

[/i][/u]

[Brian Cheney]

The ZR1600 is equipped with a 1600VA toroid.

[PJ]

Warner,
My amp is rated at its actual power output. I'm not interested in inflating specs of my amps.  The stereo amp does 250 watts RMS per channel into 4 or 8 ohms. The limiting power factor in my amp is the size of the power transformer.  I used a 500 VAC, which can supply 500 watts of continuous power. Instantaneous power is handled by the capacitor banks, which is 500/250 watts per channel into 4/8 ohms. The monoblock version will do 500 watts RMS into 4 ohms, because there is only one power mo ...

Careful....a 500VA transformer can not supply 500W continuously, usually.. I cant remember off the top of my head, but i think its called the power factor....it has to do with the impedance of the load, and the ratio of complex(?) power to real power..etc...sorry that was a few years ago now..

[KevinW]

Actually in a Class D amp, the power transformer can get very close to the total rated power.  The LC Audio modules are about 94% energy efficient, so very little of the transformer's power is wasted as heat.  Contrast that to most analog SS amps, which are in the 20-50% efficiency range.

[Vic]

I've posted this on other sites. I've replaced a QSC 2402PLX in my electric bass rig with the ZR1600. According to the resent mesurments I now have less than half the power of the QSC yet I have more headroom. The signal going to the 400 watt Bag End subwoofer is much cleaner, more defined than with the more powerful QSC. My 150watt HCA did run out of steam in the bass rig, so far the Carver has been up to the task. I can't imagin 50 watts would make such a difference.

If your looking for well above average sonics at a realistic price these designs (PS Audio Spectron Carver-Pro Bel Canto etc.)  are nothing to be warry of. If your looking for tubed style coloration without the hassle of tubes. this ain't it. You'll hear many people say the the midrange of these amps is tube like. Well, maybe a little, what I feel people are hearing is a dramatic drop in fatigue causing artifacts. These amps are easy to listen to even at high volumes.

Your first impression of their bass will be that it sounds lean. It's not at all lean its simply correct, not bloated or colored. Listen to Brian Brombergs "Wood" or "Jaco" and Patricia Barber recordings to hear some very well recorded double bass. If your speakers are up to the task, these recordings can bring the sound of a double bass into your room.

[_scotty_]

For anyone interested in the subject, here is a link to Bruce Hofer's
paper "Measuring Switch-mode Power Amplifiers"  http://www.audioprecision.com/ftp/publications/technical_papers/Measuring_Switch-mode_Power_Amplifiers_web.pdf . Interesting reading for the technically  inclined.