NEW TOP RUDISTOR - Page 7

Cheque books at the ready!

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Originally Posted by alota 

easy man 

ragazzo pazzo 

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Originally Posted by DaveBSC 

 

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.

 

Again, very interesting. The graphs published by B&O are for 1KHz where the module performs nicely-enough.

I'm afraid I don't hear images floating above my speakers on any of my amps, including class A/B. I get a very good horizontal soundstage, and good depth on all of them (class D and class A/B), but I can't say that there's much going on vertically on any of them.

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Originally Posted by visualguy 

Again, very interesting. The graphs published by B&O are for 1KHz where the module performs nicely-enough.

 

I'm afraid I don't hear images floating above my speakers on any of my amps, including class A/B. I get a very good horizontal soundstage, and good depth on all of them (class D and class A/B), but I can't say that there's much going on vertically on any of them.

 

Hmm. What speakers are you using? With good positioning (tweeters at or slightly above ear level, depending on the speaker) I've not really had any trouble getting a nice amount of stage height from most speakers, even with relatively low-end A/B amps like my old Parasound. As with all aspects of soundstaging, two-way monitors are better at this than mid-level floor standers, but even with those the image usually extends at least a good foot or two above the top of the cabinet.

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Originally Posted by DaveBSC 

Hmm. What speakers are you using? With good positioning (tweeters at or slightly above ear level, depending on the speaker) I've not really had any trouble getting a nice amount of stage height from most speakers, even with relatively low-end A/B amps like my old Parasound. As with all aspects of soundstaging, two-way monitors are better at this than mid-level floor standers, but even with those the image usually extends at least a good foot or two above the top of the cabinet.

 

How would the speakers make the sound appear to come from 2ft above the cabinets? Horizontal positioning can be achieved with stereo imaging, but I don't see how you can achieve vertical positioning, and I'm not sure how or why it would be used in music.

The distortion of 0.3% shown in the graphs for the ICEpower in the treble area is still quite low... Distortion was supposedly cut in half or so in the newer ASX2 modules (such as the ones used in the Bel Canto REF500M). Regardless, even 0.3% is not something that I would expect to be able to hear, and indeed I can't detect any problems with the treble.

I've pretty much stopped using class A/B amps - they're big, heavy, run hot, consume a lot of electricity, and they require turning on and off. I just keep my class D amps on all the time. I don't detect any sound difference, so I don't see the point in putting up with the disadvantages of class A/B.

I have multiple speakers setups, mostly Dali and Focal.

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Originally Posted by visualguy 

 

How would the speakers make the sound appear to come from 2ft above the cabinets? Horizontal positioning can be achieved with stereo imaging, but I don't see how you can achieve vertical positioning, and I'm not sure how or why it would be used in music.

 

The distortion of 0.3% shown in the graphs for the ICEpower in the treble area is still quite low...

 

Same way the speakers are able to make sound appear to the inside and outside of the cabinets. "Disappearing" as the source of sound is the hallmark of any good speaker. A few years ago I was in Boulder, CO and I stopped in at the PS Audio factory. Their demo system was one of their Gaincell digital amps driving a pair of Avalon Eidolons. I listened to a couple of my treble focused reference tracks, and I remarked to one of the guys there that the stage height seemed artificially flat, and it stopped pretty much right at the top of the speaker cabinets. He said "yeah, digital can sound different in that way". The Gaincell amps weren't ICEpower modules, but the sound was pretty similar.

I wouldn't consider 0.3% distortion to be low. IIRC, 0.1% is the threshold of audible distortion, and these are well above that. It's an order of magnitude higher than the linear amps. I certainly get the convenience factor of Class D, a 20lb. amplifier that can chuck out hundreds of watts, with its own power regulation, that consumes all the power of a CFL light bulb while idling. Compared to that, Class A with its heat, limited output, and ravenous power appetite seems just silly. I just don't think there's an amplifier free lunch yet - there are compromises for all of that convenience.

Given the technology available, I think the amps that start out in Class A and then slide into A/B as output climbs past 10 or 20 watts are still the best overall compromise. Yes they'll probably weigh 50 or 60lbs, but that's not really a concern assuming they are staying in place. Many of them have standby modes which keep the most critical components powered, while consuming under 50 watts.

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Originally Posted by DaveBSC 

 

Given the technology available, I think the amps that start out in Class A and then slide into A/B as output climbs past 10 or 20 watts are still the best overall compromise. Yes they'll probably weigh 50 or 60lbs, but that's not really a concern assuming they are staying in place. Many of them have standby modes which keep the most critical components powered, while consuming under 50 watts.

What are some such amps? The only one I know of which is reasonably priced is the Parasound A21. Another one might be the Bryston 4B-SST2, but I think that one runs entirely in Class AB. Not sure if either one of these sounds better than ICEpower ASX2 modules, though.

Way back, I was thinking about getting Parasound JC1 monoblocks, but they generate a tremendous amount of heat (250W idle each!)

The prices of Class A/AB amps have been going up like crazy over the last few years, by the way...

How much does the new Rudistor amp cost ? Hopefully it'll be cheaper than the RP-1000 MKII was about 3 years ago . Maybe it was 2 years ago ... Whatever, when I bought it doesn't matter .

Rudistor is looking for help, but I have a feeling few french people fit the profile in regards to vegan policy. Yes, you'd better be a vegan to join the team, apart from that, no discrimination whatsoever ;) 

<<We do not make distinction in sex race and religion, but we adopt a severe banning policy on smoking, and alcohol, our collaborator are preferably vegan or vegetarian ( no BBQ with us ) we are looking for:...>>

http://www.rudistor.com/call.htm

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Originally Posted by arnaud 

Rudistor is looking for help, but I have a feeling few french people fit the profile in regards to vegan policy. Yes, you'd better be a vegan to join the team, apart from that, no discrimination whatsoever ;) 

 

<<We do not make distinction in sex race and religion, but we adopt a severe banning policy on smoking, and alcohol, our collaborator are preferably vegan or vegetarian ( no BBQ with us ) we are looking for:...>>

 

http://www.rudistor.com/call.htm

Not just regarding the vegan policy. Smoking and Alcohol as well :D.

Must have a clear head to join RudiStor!

Waiting for the Rp2000 vs Liquid Fire thread ...

That guy is seriously strange.

Quote:

Originally Posted by arnaud 

Rudistor is looking for help, but I have a feeling few french people fit the profile in regards to vegan policy. Yes, you'd better be a vegan to join the team, apart from that, no discrimination whatsoever ;) 

 

<<We do not make distinction in sex race and religion, but we adopt a severe banning policy on smoking, and alcohol, our collaborator are preferably vegan or vegetarian ( no BBQ with us ) we are looking for:...>>

 

http://www.rudistor.com/call.htm

That's a seriously strange job offer, I can understand the smoking part but that's normally already covered by whatever laws their country has; not drinking on the job is self-evident too, but the way it's phrased seems to suggest a stricter rule ? And lastly the vegan rule seems out of place, AFAIK, no collaborator will force you to eat their food and not tolerating someone bringing meat at work would be discriminatory in most countries.

PS: Why French people? I don't think Rudistor is a French company, aren't they Italian?
 

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Originally Posted by khaos974 

 

PS: Why French people? I don't think Rudistor is a French company, aren't they Italian?

Indulging in national stereotypes, I'd say : even worse then to find a candidate responding to the veggan criteria :D.

Seriously, I agree, that's a most strange job offer.