Welcome to the (virtual) listening room.

Which amplifier do you prefer ?

  • Amp 1

    Votes: 4 30.8%

  • Amp 2

    Votes: 4 30.8%

  • Amp 3

    Votes: 5 38.5%
  • Total voters
    13
  • Poll closed .
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#41
Markw4 said:
Okay. I would suggest that most people seem to get more accurate simulation results if they upsample the wave file first, run it through the simulator, then downsample. If any distortion is added by the model, it may violate nyquist and produce aliasing. Upsampling usually at least helps. Depending on how high-order the amplifier model distortion is, of course.
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Mark,
all three stimulus are under the same conditions thus it does not matter what is added or left out, they are in fact normalized to each other. To me all three sound slightly different, not easy to lay a finger on it, but one of the files does sound more natural, nice or whatever you may want to call it.

Maybe the vote should have been in order of preference and Mooly should not shown any simulated data at all. Next time, he can reveal it after the vote.
 
#42
If the amp models sound different, how can that be due to anything other than differences in distortion?

And if there is nonlinear distortion, then there is a good probability of aliasing.

There could be linear distortion, frequency distortion, phase distortion.

There could be volume differences, I guess, which would not be classified as distortion.
 
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#43
Thanks for listening and voting Nico 🙂 And Nico is right, we need more listeners and voters.

Nico Ras said:
Removing all the other added noises out of the experience in order the evaluate the design probably puts audiophiles in a predicament that they are not listening to equipment.
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That's an interesting angle to it all.

Lets hope we have some more votes when I look in tomorrow.
 
#44
Markw4 said:
If the amp models sound different, how can that be due to anything other than differences in distortion?

And if there is distortion, then there is a good probability of aliasing.
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What I meant Mark was that there is no need to process the outputs further, you actually want the raw data as presented by the design. Up-sampling cannot improve the data, if it does then it is flawed.
 
#45
Nico Ras said:
What I meant Mark was that there is no need to process the outputs further, you actually want the raw data as presented by the design. Up-sampling cannot improve the data, if it does then it is flawed.
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IIRC, if you run a signal through a second order polynomial transfer function distorter, you will produce nothing more than 2nd harmonic distortion. Third order polynomial, nothing over 3rd harmonic.

People who write VST plugins that add distortion have to be very careful about this. If you know a distorter cannot produce more than 2nd order harmonics, then upsampling to twice the original sampling frequency is adequate to prevent aliasing. And so on.

Why? Suppose you record at 44.1kHz, then no frequencies over about 21kHz can exist. If you upsample to 88.2, there is still nothing over 21kHz. So if you add 2nd harmonic distortion at that point, the highest frequency you could produce would be 42kHz, which is not high enough to alias because you are now sampling at 88.2 kHz. Make sense?
 
#49
Mooly said:
You mention bass quality. My own amp (not these under test here) has an added 0.22 ohm series resistance in the speaker feed.
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The resistor might protect the amplifier, but I don't know if such low resistance will affect damping (audibly). Once, I used 10 Ohm (note that this is a lot bigger than 0.22) at the output and a listener was sooo amazed with the bass quality.

I think I also favor a 'fake' bass. The real problem is not the bass itself. If the 'fake' bass (which is subjectively favorable) is the consequence of a design decision (if it is ever a decision) that affects other things too, the problem can be an inaccuracy somewhere else, like timbre etc. which will ruin the music.
 
#51
Been sitting in the office for 20 minutes trying to hear difference between them using a B&W P5 S2 headset, and I'm not sure if I could hear it or not. There's lots of noise leaking into my headset from computer fans and a noisy gas generator, so I have to try again later in a quiet room.
 
#52
Lojzek said:
Did some 20 minutes of comparing and I can't be sure that there is any significant difference but very small one, if I'm not imagining. Gave my vote.
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Thanks :up:

scottjoplin said:
Hi. Difficult. Too short I think, and I'm only listening through Grados plugged into laptop. The
first gets my marginal preference. Which is that?
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Time is the killer doing these. The simpler circuits run reasonably quickly, the complex FET amp does not, particularly if run as a stereo pair.

Hopefully we might get some more votes and comments before I call time and reveal all.
 
#54
Out of respect for Mooly's hard work, I gave the files a listen on the NS-10s. Mostly listened between 0:43 and 0:45, where there is a break in a vocals and a cymbal hit at around 0:43.6.

Impressions are as follows:
Amp1 - Cymbal hit sounds brighter than Master file, probably due to added harmonic distortion. Instruments sound brighter too.
Amp2 - The brightest and most distorted. One could say the distortion is muddy in the midrange frequencies, among other things.
Amp3- The cleanest sounding, most like the master file, but still some increased brightness, presumably due to added harmonics.
 
#58
Thank you 🙂

Listening with headphones seems to be the most accepted method. Its certainly the way I have done all the listening run by others in the past.

Its a good mix of comments and impressions we have here.
 
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