Volunteer sir sanders zingmore Posted January 15, 2021 Volunteer Share Posted January 15, 2021 13 minutes ago, Ittaku said: And that's very interesting considering both would allegedly be below the threshold of hearing difference according to ASR's own bullshit thresholds. But not when they are clipping. (I know, I know, again with the clipping) I think the error that the ASR crowd makes is probably not about audibility thresholds for amps, it’s about how much power you need in order to avoid clipping. Link to comment Share on other sites More sharing options...
kukynas Posted January 15, 2021 Share Posted January 15, 2021 5 minutes ago, Ittaku said: I've compared my NC400s to my ARC power amps many times - no contest. Bridging amps makes them less able to tolerate low impedance, not the other way around. you right especially in your case where each module would see 1 ohm load Link to comment Share on other sites More sharing options...
Ittaku Posted January 15, 2021 Share Posted January 15, 2021 13 minutes ago, sir sanders zingmore said: I think the error that the ASR crowd makes is probably not about audibility thresholds for amps, it’s about how much power you need in order to avoid clipping. Fair call, but the NC400 and Purifi ET1400A should deliver identical current and virtually the same power. Link to comment Share on other sites More sharing options...
frednork Posted January 15, 2021 Share Posted January 15, 2021 1 hour ago, AudioGeek said: I cant remember if it was on this forum or on ASr, but March conducted a blind test between his Ncore and Purifi amps and all participants could pick a difference. Be interesting to see what @Ittaku finds. Would be interested in a link to this if you have it Link to comment Share on other sites More sharing options...
Grizaudio Posted January 16, 2021 Share Posted January 16, 2021 (edited) 5 hours ago, sir sanders zingmore said: But not when they are clipping. (I know, I know, again with the clipping) I think the error that the ASR crowd makes is probably not about audibility thresholds for amps, it’s about how much power you need in order to avoid clipping. How much power one needs is dependant on so many factors. I suspect I would rarely if ever hit clipping, with my 20watts. Honestly, I'm not sure this is an issue everyone would have. Too many assumptions. For instance multiway amplifier setups reproducing small acoustic bandwidths would not suffer as much as full range amplifiers. High sensitivity setups also only require very few watts to operate optimally at very high SPL's. Distance to speakers, required SPL, room size, easy to drive impedance profiles, personal hearing etc all mean this position is not necessarily valid or important. Edited January 16, 2021 by Grizaudio 1 Link to comment Share on other sites More sharing options...
LHC Posted January 16, 2021 Share Posted January 16, 2021 6 hours ago, sir sanders zingmore said: But not when they are clipping. (I know, I know, again with the clipping) I think the error that the ASR crowd makes is probably not about audibility thresholds for amps, it’s about how much power you need in order to avoid clipping. This goes back to my question about consensus on clipping earlier. Surely the ASR crowd being measurement enthusiasts should be well placed to tell if their amps are clipping. It shouldn't come down to a question of how much power they need - they could determine that for themselves. Link to comment Share on other sites More sharing options...
Volunteer sir sanders zingmore Posted January 16, 2021 Volunteer Share Posted January 16, 2021 50 minutes ago, Grizaudio said: How much power one needs is dependant on so many factors. I suspect I would rarely if ever hit clipping, with my 20watts. Honestly, I'm not sure this is an issue everyone would have. Too many assumptions. For instance multiway amplifier setups reproducing small acoustic bandwidths would not suffer as much as full range amplifiers. High sensitivity setups also only require very few watts to operate optimally at very high SPL's. Distance to speakers, required SPL, room size, easy to drive impedance profiles, personal hearing etc all mean this position is not necessarily valid or important. Of course in specific cases, specific requirements are different. I was generalising for "typical' users - speakers with passive crossovers, average efficiency (high '80s or so) in typical rooms at typical volumes. That covers enough of the audio world for me to be very comfortable saying that most people are listening to the sound of their amps clipping. 1 Link to comment Share on other sites More sharing options...
davewantsmoore Posted January 16, 2021 Share Posted January 16, 2021 On 14/01/2021 at 12:33 PM, sir sanders zingmore said: Out of interest I looked at some other Pass Labs amps and it seems the 30.5 has significantly more 3rd harmonic than second. I assume this is also a deliberate design choice The Pass range and First Watt range are very different animals. Link to comment Share on other sites More sharing options...
davewantsmoore Posted January 16, 2021 Share Posted January 16, 2021 On 13/01/2021 at 10:04 PM, Steffen said: But that’s like saying “I trust my own eyes, and I’m telling you that space B is of a lighter shade than space A, science and measurements be damned”. This. 10 thousand million percent.... this. 1 Link to comment Share on other sites More sharing options...
kukynas Posted January 16, 2021 Share Posted January 16, 2021 (edited) 7 hours ago, LHC said: a question of how much power they need - they could determine that for themselves. nope, nobody can predict it unless you measure every potential combination of amp, speaker and type of music.... Edited January 16, 2021 by kukynas deleted picture Link to comment Share on other sites More sharing options...
LHC Posted January 16, 2021 Share Posted January 16, 2021 54 minutes ago, kukynas said: nope, nobody can predict it unless you measure every potential combination of amp, speaker and type of music.... I think there is some confusion in the current discussion. There are two somewhat related, but yet different concepts: Having more power, and therefore more dynamic headroom, allows an amp to drive speakers (especially difficult speakers) to play dynamic music well (compared to lesser power amps) Different amps can sound different only because they don't have enough power and are clipping all the time. The way amps clip are different and this result in a difference in sound that is audible (and enjoyable to tube amp lovers) Your video described the first scenario, and I agree with that concept. The video did not address the second scenario as it didn't measure clipping (although it mentioned compression). Link to comment Share on other sites More sharing options...
kukynas Posted January 16, 2021 Share Posted January 16, 2021 agreed but I was referring mainly to the point that it's hard or impossible to measure power output and potential clipping of an amp if we don't know or can't predict the load due to fact each speaker and music played would represent different and variable load that specific amp see, video just demonstrate how does it look under same condition but different music playing and if only music content can represent such difference than imagine how more variable the load would be if you connect different type of speakers Link to comment Share on other sites More sharing options...
Upgrayed Posted January 17, 2021 Share Posted January 17, 2021 There is a lot to take in from this interview. Bruno claims that he has mathematically solved the feedback that is applied to his design. This has the effect of making the design load invariant. A first for class d. His work with solving distortion in speaker drivers has seen Dr Rod Crawford replace the Seas Magnesium upper bass driver with Purifi in his Tikandi Grande BE. We may all be like Darko soon, room full of Bruno"s work. Link to comment Share on other sites More sharing options...
Steffen Posted January 17, 2021 Share Posted January 17, 2021 1 hour ago, deblur said: This has the effect of making the design load invariant. A first for class d. A powerful, load-invariant class-D amplifier would make a nice mains power supply. Just feed it a 50Hz tone, set the volume so it produces a certain output voltage (load-invariant) and transform that up to 240V. 1 Link to comment Share on other sites More sharing options...
rand129678 Posted January 17, 2021 Share Posted January 17, 2021 On 13/01/2021 at 8:01 PM, Steffen said: What I cannot go along with is when people insist that there are actual differences in the music reproduction, that some people with golden ears can hear, but instruments can’t measure. https://phys.org/news/2013-02-human-fourier-uncertainty-principle.html 4 Link to comment Share on other sites More sharing options...
Upgrayed Posted January 17, 2021 Share Posted January 17, 2021 1 hour ago, Steffen said: A powerful, load-invariant class-D amplifier would make a nice mains power supply. Just feed it a 50Hz tone, set the volume so it produces a certain output voltage (load-invariant) and transform that up to 240V. Do you believe there are audiophiles out there who pay for your idea. Link to comment Share on other sites More sharing options...
Steffen Posted January 17, 2021 Share Posted January 17, 2021 Cheque or Paypal is fine Link to comment Share on other sites More sharing options...
aussievintage Posted January 17, 2021 Share Posted January 17, 2021 10 hours ago, Steffen said: A powerful, load-invariant class-D amplifier would make a nice mains power supply. Just feed it a 50Hz tone, set the volume so it produces a certain output voltage (load-invariant) and transform that up to 240V. 9 hours ago, Steffen said: Cheque or Paypal is fine Sorry, some of us have been doing this, even with call AB amps, for smaller loads for a long time. Not really new. Makes a nice motor speed control for AC motors. Link to comment Share on other sites More sharing options...
Ittaku Posted January 18, 2021 Share Posted January 18, 2021 On 16/01/2021 at 8:18 AM, frednork said: Would be interested in a link to this if you have it I scoured the ASR site for a while and I couldn't find said blind comparison and my google foo also failed to find it so no idea where it is. 1 Link to comment Share on other sites More sharing options...
davewantsmoore Posted January 20, 2021 Share Posted January 20, 2021 On 16/01/2021 at 9:53 PM, kukynas said: nope, nobody can predict it unless you measure every potential combination of amp, speaker and type of music Sure you can.... for a specific speaker. The type of music is irrelevant.... All that matters is the input signal max size ... speaker sensitivity (complex, ie. impedance phase), and the desired SPL. Link to comment Share on other sites More sharing options...
kukynas Posted January 20, 2021 Share Posted January 20, 2021 3 hours ago, davewantsmoore said: Sure you can.... for a specific speaker. The type of music is irrelevant.... All that matters is the input signal max size ... speaker sensitivity (complex, ie. impedance phase), and the desired SPL. sure you can if you know which speaker and music content, but that’s not the real life case, manufacturer or reviewer doesn’t know your specific speaker or music content when providing data sheets figures or measurements so all they can do is to take some industry standard scenario and provide those figures based on that which in mamy cases might be completely off of your situation or requirements Link to comment Share on other sites More sharing options...
March Audio Posted June 27, 2021 Share Posted June 27, 2021 (edited) On 16/01/2021 at 6:07 AM, Ittaku said: And that's very interesting considering both would allegedly be below the threshold of hearing difference according to ASR's own bullshit thresholds. The difference lies with the frequency response of the amps. The Purifi has a slight but audibly more "extended and sweet" high frequency range. The Purifi is flat to beyond 20kHz. The hypex amps actually have a slightly HF roll off, maybe 0.4dB down at 20kHz. In itself and in isolation, a drop of that level at 20kHz won't be audible, however this roll-off starts below 10kHz. This makes it audible. The difference is small, but it's there. I will try and dig out some of the research papers, but response deviations over a *wide* frequency range as low as 0.1dB can be audible. Edited June 27, 2021 by March Audio 1 Link to comment Share on other sites More sharing options...
LHC Posted June 27, 2021 Share Posted June 27, 2021 9 minutes ago, March Audio said: The Purifi is flat to beyond 20kHz. The hypex amps actually have a slightly HF roll off, maybe 0.4dB down at 20kHz. In itself and in isolation, a drop of that level at 20kHz won't be audible, however this roll-off starts below 10kHz. This makes it audible. Good point. It also means one has to be super careful in the way we frame and discuss 'the limit of audibility'. 9 minutes ago, March Audio said: I will try and dig out some of the research papers, but response deviations over a *wide* frequency range as low as 0.1dB can be audible. That would be the research by Toole as discussed in other places of this forum. Link to comment Share on other sites More sharing options...
March Audio Posted June 27, 2021 Share Posted June 27, 2021 Just now, LHC said: Good point. It also means one has to be super careful in the way we frame and discuss 'the limit of audibility'. That would be the research by Toole as discussed in other places of this forum. There were other papers I found on the subject but, yes Toole does talk about this. 1 Link to comment Share on other sites More sharing options...
LHC Posted June 27, 2021 Share Posted June 27, 2021 1 hour ago, March Audio said: There were other papers I found on the subject but, yes Toole does talk about this. Yes, please share. Link to comment Share on other sites More sharing options...
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