Agree.
If you want to correlated the measurement and the sound, please make one variable is significantly different and others are similar, although it is very difficult. Because one variable usually affect to another variable. Example: Make amplifier with optimal compensation and very overcompensated. This is affect of the slew rate and the distortion at high frequency. And then you will know how slew rate make sound different. Etc.
If you do in many kind of measurement, you can make prediction how amplifier sound in particular speaker, although it can not 100% accurate. People tend to judge many variable at same times. If you do not train to listen at one variable at one time, you CAN NOT correlated any measurement with the sound. Some time the recording play big role. Example: if you use very low dynamic in the recording, you will difficult to make analysis of the slew rate.
Hi Chris,
I agree with your analysis, indeed we have not yet decided what amplifier circuit topology we will develop.
Surely we will try both vacuum tube and solid state circuits, then we will measure them, but the final verdict will be that of our ears.
As I said we are not professional so we need very long time to develop our reference system.
Now we are working on the digital front end and on the DAC, it will take at least one year, maybe more.
Of course, we have our own fixed points that we follow during development, even if we are absolutely willing to change our minds during development.
For example in our thinking the source and the DAC have to be well isolated working in different time domains.
Now we are just working on this.
Andrea
I agree with your analysis, indeed we have not yet decided what amplifier circuit topology we will develop.
Surely we will try both vacuum tube and solid state circuits, then we will measure them, but the final verdict will be that of our ears.
As I said we are not professional so we need very long time to develop our reference system.
Now we are working on the digital front end and on the DAC, it will take at least one year, maybe more.
Of course, we have our own fixed points that we follow during development, even if we are absolutely willing to change our minds during development.
For example in our thinking the source and the DAC have to be well isolated working in different time domains.
Now we are just working on this.
Andrea
There are a pair of new versions developed in the last years after the TWTMC.
They are the DRIXO oscillator (new Driscoll version) and the EXO oscillator (which uses a npn matched pair developed for audio).
Both perform in the region of the best oscillators on the market as you can see from the phase noise plot I have published above.
Hi Andrea,
As long as you pay attention to the measurements and listening tests, you should do well. But if they disagree your design is faulty and it will not sound good compared to the real event, or equipment that is actually good. You need good audio equipment in order to do anything useful. The equipment will show you a spectrum of the audio output, at least to near 100 KHz. Using equipment not up to the task isn't very useful, so you need access to very good equipment.
As long as you pay attention to the measurements and listening tests, you should do well. But if they disagree your design is faulty and it will not sound good compared to the real event, or equipment that is actually good. You need good audio equipment in order to do anything useful. The equipment will show you a spectrum of the audio output, at least to near 100 KHz. Using equipment not up to the task isn't very useful, so you need access to very good equipment.
I'd be very cautious in making a statement like so since someone we both know may accuse you of being a shill (for a good equipment maker or something).
Some need to understand also that saying something like "DAC measure don't equate listening impression" is tricky - how can one listen to *only* a DAC. Well, its not possible - one need to do it via at least a source, an amp and a speaker. So we can never listen to a DAC. A DAC will interact with the source and the amp depending on interface properties - unfortunately these interfaces are not standardised. To measure the difference between two DAC doing acoustical measurements I have not seen yet... But measure on a DAC - that one can do. But not listen to one. One can listen to a system with a specific DAC in its chain. But thats not listening to the DAC.... most get this....
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Considering that Andrea has said they were above personal bias in their evaluations, I’m sure their auditory memory of their favorite performances is a perfect reproduction
Hi Indra,
Okay, I do push using good equipment. Otherwise I think you are wasting your time.
There are many good makes of used and new test equipment. It's no secret that I use HP / Agilent / Keysight where possible because I believe it is the best for most equipment. It also represents the best value since it tends to retain calibration very well. So, buy it used, or new. I have just added a bunch of new Keysight equipment to my bench. I can't afford not to.
If you ever see an RTX 6001 up for sale, grab it! It was developed by a member here and is incredible value, and performance. I use one, otherwise I would need an Audio Precision or Keysight. There are other good ones out there too. For this purpose, a sound card can be used, but you need an excellent front end for it. You can't run most equipment into the inputs of a sound card without blowing it up.
#1, buy a good bench meter with AC response out to at least 100 KHz, or 300 KHz like the current bench meters (like Keysight). I just got a 34465A to replace a 27 year old 34401A I killed in error. It's amazing, but any Keysight would be great, like a 34461A or their new EDU series (5 1/2 digit).
If you're going to buy something, buy something you can trust!!!
-Chris
Okay, I do push using good equipment. Otherwise I think you are wasting your time.
There are many good makes of used and new test equipment. It's no secret that I use HP / Agilent / Keysight where possible because I believe it is the best for most equipment. It also represents the best value since it tends to retain calibration very well. So, buy it used, or new. I have just added a bunch of new Keysight equipment to my bench. I can't afford not to.
If you ever see an RTX 6001 up for sale, grab it! It was developed by a member here and is incredible value, and performance. I use one, otherwise I would need an Audio Precision or Keysight. There are other good ones out there too. For this purpose, a sound card can be used, but you need an excellent front end for it. You can't run most equipment into the inputs of a sound card without blowing it up.
#1, buy a good bench meter with AC response out to at least 100 KHz, or 300 KHz like the current bench meters (like Keysight). I just got a 34465A to replace a 27 year old 34401A I killed in error. It's amazing, but any Keysight would be great, like a 34461A or their new EDU series (5 1/2 digit).
If you're going to buy something, buy something you can trust!!!
-Chris
No, it is just reproducing the sound with the original timbre of the instrument.
We can all recognize the sound of an instrument (I mean those of a symphony, jazz, melodic, etc., not rock orchestra, which is played electronically amplified, although rock enthusiasts will say that it is easy to recognize a Stratocaster from a Gibson) even if it is irradiated by a tiny transistor radio or a smartphone. But from there to that sound being the same as a sax in the reality, there is a very long way.
Have you heard one near you ? Or a piano?
Personal tastes generally do not conform to the people who attend live shows, rockers again excluded. But everyone can listen to a musical reproduction in any way they please, of course, and it is absolutely respectable. No one can impose his personal tastes on another, as in a meal or a drink.
Or in the preference of certain women's bodies, for example.
I once asked a friend:
Do you like women with many boobs?
Nooo, more than two impress me, he replied!
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@TNT
The problem I see here is like the Butterfly Effect, we have people saying Butterfly wings produce negligible wind measured at the DAC output, but others are complaining about tornadoes listening to the acoustic output (which is hardly measured). Hail Chaos theory, let the dog fight prevail.
@syn08
You are to far I can not hear your stuff. No contest, mine sounds better, I can hear it.
@anatech
Thank you Chris, I was only trying to lighten up the mood, don't worry about it. I'm no audio professional, keeping my boat afloat is difficult enough for me these days. No equipment budget for me in the near future. It's only a hobby after all.
The problem I see here is like the Butterfly Effect, we have people saying Butterfly wings produce negligible wind measured at the DAC output, but others are complaining about tornadoes listening to the acoustic output (which is hardly measured). Hail Chaos theory, let the dog fight prevail.
@syn08
You are to far I can not hear your stuff. No contest, mine sounds better, I can hear it.
@anatech
Thank you Chris, I was only trying to lighten up the mood, don't worry about it. I'm no audio professional, keeping my boat afloat is difficult enough for me these days. No equipment budget for me in the near future. It's only a hobby after all.
I agree, it’s the system as a whole...... Is there anyone currently offering a complete mid/high end audio ‘system’ from source to speaker that takes this into consideration?
I suppose most can’t afford everything at once but you could still piece it together as funds were available.
Or better yet is there any reviewers who put together systems from different brand components based on testing for component compatibility?
Old stuff but, nevertheless, mine sounds much better.
Of course, like your phono stage with tons of feedback.
Anyway it's enough clear you are not able to design a decent oscillator.
Not a big surprise, it was almost obvious for me.
Wondering if noise modulation in high loop gain amplifiers is one problem. Attached below is the harmonic spectrum of one viola. Consider then the number of frequencies generated by a orchestra where instruments are never perfectly in tune with each other. There might be 10,000 distinct frequencies present at once. What if a slight signal-correlated change in noise is happening from each distinct frequency signal. The sum total of that dynamically changing noise may be what buries musical details in SOA measuring amplifiers. Why do I come up with this hard to believe conjecture? Because a modified Aragon 8008 revealed more musical details that Benchmark AHB2. That so, despite the Aragon having audibly more IMD. Something has to be wrong with our models of what is happening.
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Exactly. That sounds great too. No surprise, it has -194dB phase noise.
Ok, I'll take the bait, so what are the X and Y axes on this chart, and how do you interpret the results? Where is the noise modulation effect?
That is a conjecture on you part. I for one don't like the effects, but some people are willing to overlook the effects in order to improve something else we are failing to look for.
I don't claim to have all the answers at this point. I am just trying to consider possible physical explanations other than to assume that everything is explained by human hallucination. To my ears, AHB2 buries some musical details in some kind of noise. That seems like what might be happening when other people have described some low distortion circuits as loosing details, "some of the details just disappear." So they argue that feedback loses information. Maybe it just hides information. Not due to basic control theory of course, but real circuits are not ideal. The model in an engineer's head is only so good at representing the physical world.
The first recorded observation of a soliton wave preceded its physical scientific explanation. It turned out not to be a hallucination. It took time to figure out the cause.
Regarding critics, its normal for some people to scoff when their preexisting beliefs are at stake.
The first recorded observation of a soliton wave preceded its physical scientific explanation. It turned out not to be a hallucination. It took time to figure out the cause.
Regarding critics, its normal for some people to scoff when their preexisting beliefs are at stake.
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Exactly. The cult of feedback meets the cult of PLL.
Pity that the measurements you trust so much demonstrate you are not able to design a decent oscillator.
Your smart design is very poor, this tells us your measurement.
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