[alota]

you know the hypex modules? ( www.hypex.nl)
many people, who have tried, are pleased with the performance
Quote:

Rowland sells chip amps in $7500 boxes. As far as I'm concerned his credibility is near zero. The only Class D amp I think is remotely good is the Spectron, which has a big old linear transformer in it. The refinement of the B&O amps, particularly in the treble region is pretty bad.

 

 

[gurus]

you know the hypex modules? ( www.hypex.nl)
many people, who have tried, are pleased with the performance
 

I have a Pioneer that uses Ice amps. Maybe for a HT receiver it sounds good but when I compare it to my Proceed amps (using the preamp out of the Pioneer) the sound is colored with little or no definition and detail.

 

[DaveBSC]

Quote:

 
Any idea why this treble problem isn't showing up in measurements? The datasheet shows awesome performance throughout the audible frequency range and beyond...
 

I noticed something when looking at some amplifier reviews on Stereophile.
 
10Khz square wave response from the Mark Levinson 532H:
 

 
10Khz square wave response from the Class A Musical Fidelity AMS100:
 

 
10Khz square wave from the Bryston 7B SST2:
 

 
10Khz square wave from the Bel Canto Ref1000M (G2):
 

 
Ruh-roh. One of these things is not like the other. Both the pure Class A and the A/B amps produce nice and neat square waves at 10Khz. The Bel Canto's (generally regarded as one of the better implementations of the ICEpower module in the G2 version) is a mess. The measurements aren't as good as you think they are. There isn't the 500Khz noise blast that more old fashioned Class D produces as in the Halcro MC amps, but I'm not seeing neutrality there.
 

 

 

[n3rdling]

That's pretty bad.

 

[jjinh]

Looks like some specs are back...
 
 

 

[mwilson]

Either I'm a moron or this doesn't make sense:
 
(4th paragraph under 2. Basics)
 
"[size=x-small]When on normal operation the screen indicate the main voltage ( a complete check is performed every second in background) while the right screen indicate the sound pressure level for each channel[/size]"
 
Isn't SPL a function of the driver and its efficiency, pads, distance from eardrum... etc? Meaning, the amp has no way of knowing what the effective SPL is. And I'm not even going into the weighting aspect.

 

[DaveBSC]

Quote:

Isn't SPL a function of the driver and its efficiency, pads, distance from eardrum... etc? Meaning, the amp has no way of knowing what the effective SPL is. And I'm not even going into the weighting aspect.

Indeed. SPL is measured with microphones, not amplifiers. Two different drivers could produce wildly different SPL at a given W.

 

[gurus]

Give the guy a break. You know Rudi is not proficient in English. The specs should have read "Sound levels" as the dancing lights look like a sound level meter..

 

[arnaud]

Sound level and SPL is exactly the same meaning. You're being too kind with the english excuse. In that case, any of specs may have "translation" mistakes like 0.001% thd instead of meaning 0.001= 0.1/100=0.1% lol .

I'll guess he did mean to display as "volume level" but it didn't fit in the bling bling display because of huge font size

 

[mwilson]

You mean like a VU meter?  

 
Quote:

I'll guess he did mean to display as "volume level" but it didn't fit in the bling bling display because of huge font size

 

 

[ardgedee]

The Rudistor's meter is labeled 0 at the bottom and 100 at the top, implicitly percentage of maximum output of either power or sound pressure.
 
For comparison, the meters on McIntosh amps are labeled 0 watts --> max watts and -50 dB --> 0 dB.

 

[visualguy]

 
Quote:

 
Ruh-roh. One of these things is not like the other. Both the pure Class A and the A/B amps produce nice and neat square waves at 10Khz. The Bel Canto's (generally regarded as one of the better implementations of the ICEpower module in the G2 version) is a mess. The measurements aren't as good as you think they are. There isn't the 500Khz noise blast that more old fashioned Class D produces as in the Halcro MC amps, but I'm not seeing neutrality there.
 

 
Thanks - this is interesting, although I don't know if this square wave imperfection is something that can be heard or not.
 
I listen to violin music a lot which is rich in treble, and I've compared my ICEpower-based class D amps to my class A/B amp many times playing such music without hearing any difference. 
 
The fact that I can't detect this deficiency doesn't mean that others can't, but it does mean that the difference can't be large - my hearing isn't that bad...
 

 

[DaveBSC]

Quote:

 
 
Thanks - this is interesting, although I don't know if this square wave imperfection is something that can be heard or not.
 
I listen to violin music a lot which is rich in treble, and I've compared my ICEpower-based class D amps to my class A/B amp many times playing such music without hearing any difference. 
 
The fact that I can't detect this deficiency doesn't mean that others can't, but it does mean that the difference can't be large - my hearing isn't that bad...
 

Another interesting measurement is THD vs. frequency. Again, here's the Levinson, MF, and Bryston:
 

 


 
And now the Bel Canto ICEpower:
 

 
The Levinson just pushes past 0.05% when it's hit with 2Ohms at 20Khz. The other two do even better, staying under 0.05%, although the Bryston seems slightly odd when presented with 2Ohms. The ICEpower again, not so good. It blows past 0.1% and nears 0.5%, not just with 2Ohms either. JA's conclusion after his measurement suite was "It does work best with higher-impedance loudspeakers, however, and at lower frequencies. Fortunately, music rarely includes enough high top-octave energy to reveal the amplifier's unhappiness in this region."
 
The problem I've had with ICEpower amps is that to me, the height of the stage is reduced considerably, and there's just something not right about the treble region. Images don't float above and around the speakers, it's like a blanket has been placed over the sound, and the highs sound like they are coming right from the tweeters. It's not the "painted on" effect I've heard from some electrostats, the rest of the FR is generally OK, if not necessarily stunning. It's just not quite good enough.
 

 

[rosgr63]

Beautiful amp.
God has answered all my prayers.
Thanks Dr Stor.

 

[alota]

Quote:

Beautiful amp.
God has answered all my prayers.
Thanks Dr Stor.

easy man