John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
It may be the same or similar for ABX testing. Doing it enough to get over the stage fright might be necessary for someone to be able to perform well.

Define perform well. Any perceived pleasing of those administering the test completely invalidates the results.

You remind my of one of my kids high school graduations. A very sweet young lady played Vivaldi's "Spring" on the violin and to my disbelief you could not recognize what was being played without looking at the program. I didn't think that would be possible, but everyone was still pleased.
 
Define perform well. Any perceived pleasing of those administering the test completely invalidates the results.

You remind my of one of my kids high school graduations. A very sweet young lady played Vivaldi's "Spring" on the violin and to my disbelief you could not recognize what was being played without looking at the program. I didn't think that would be possible, but everyone was still pleased.

I wan't thinking of pleasing anybody, rather about avoiding publicly making a complete fool of yourself, even if in only your own mind.
 
I don't think I listen for noise floor. You may have trained yourself to do that, and now maybe it happens automatically.

My perspective would be different. I would ask, how do you not listen to or ignore differences in distortion?

Why would there be any distortion, there is none inherent in either format. In fact with today's technology you could probably make a perfect 16 bit (real multi-bit A/D) with proper dither there is no distortion over the noise floor.
 
But does that increase or reduce enjoyment of just kicking back and listening? Necessary in production, possibly a drawback in consumption?

Maybe. But does "production" include building amplifiers?

And speaking of a drawback in consumption, learning music can sound better on a good system than with a cellphone and earbuds might be considered a drawback by some. Maybe better not to know that...
 
I wan't thinking of pleasing anybody, rather about avoiding publicly making a complete fool of yourself, even if in only your own mind.

How do you do that in a listening test, can't hear a difference between anything? Wouldn't make me feel foolish.

BTW I just listened to one of David Lewiston's field recordings on Nonsuch that Bob L. didn't master, sounds like do-do though I suspect this is before David discovered Nagras.
 
Last edited:
For the record, I have been pretty good with A-B ... blind listening tests, at least in the past. HK tested me back in 1978, and I came through with 100% success, for example. I just don't do well with ABX testing, and I found that some others did better than me, and yet others did about the same as me. It has to be a pretty clean audio reproduce system for me to tell ABX differences.
Now for something else. Here is the deleted input stage (IC101) that was originally in the HCA2200 about 25 years ago. Why don't we build it up and see if we can hear it, or even find a measured problem with it?
What the heck, maybe I was wrong, and we could use this stage anywhere!
 

Attachments

  • Picture 19.jpg
    Picture 19.jpg
    254.8 KB · Views: 197
But does that increase or reduce enjoyment of just kicking back and listening? Necessary in production, possibly a drawback in consumption?

I began a very basic music technology course a while ago, whilst it was about using technology in composition, not in sound reproduction I had to stop because the constant analysing of the sound (product) was eroding my pleasure in simple music enjoyment and consumption. I'm glad I stopped when I did, and I certainly can just kick back and enjoy what the music is about without any mental interference.
 
Why would there be any distortion, there is none inherent in either format. In fact with today's technology you could probably make a perfect 16 bit (real multi-bit A/D) with proper dither there is no distortion over the noise floor.

To me there are missing subtle details at 16-bits, even with very good dither. Good dither does give a few more bits of signal down in the noise and helps a lot, but it still sounds like something has gone missing, not like the only thing that changed was some noise being added to the 24-bit source.

Also, for one example, Bob Katz talks about different dither options for different kinds of music in the newest edition of Mastering Audio. But none of the options are ideal for any and all kinds of music, which one is best depends on the particular music, so he says. And it still does't sound as detailed the 24-bit source, again, to him anyway.

And, to me. I can't speak for you or anyone else. However, I do find the differences of opinion puzzling. I can't help feeling like if you listened on my system you would hear it the way I hear it, but maybe not.
 
Last edited:
For the record, I have been pretty good with A-B ... blind listening tests, at least in the past. HK tested me back in 1978, and I came through with 100% success, for example. I just don't do well with ABX testing, and I found that some others did better than me, and yet others did about the same as me. It has to be a pretty clean audio reproduce system for me to tell ABX differences.
Now for something else. Here is the deleted input stage (IC101) that was originally in the HCA2200 about 25 years ago. Why don't we build it up and see if we can hear it, or even find a measured problem with it?
What the heck, maybe I was wrong, and we could use this stage anywhere!

Where did you get those 7pF caps. You needed a 2MHz time constant in an offset servo maybe it was just oscillating?!? :rolleyes:
 
Member
Joined 2014
Paid Member
Maybe. But does "production" include building amplifiers?
Not in my book. But I am doing it as a hobby to recover from the grind of the day job.
And speaking of a drawback in consumption, learning music can sound better on a good system than with a cellphone and earbuds might be considered a drawback by some. Maybe better not to know that...
Yet so many stories abound about professional classical musicians not being bothered about having a nice stereo because they can't really enjoy the music as they are listening to the performance and its such a poor facsimile of being on stage in the midst of it all. These may be totally apocryphal but there must be enough people on here with connections for at least a basic straw poll.

I would however take the risk to try and train my ear for the experience. My problem is that, by the time I some peace and quiet in the evenings to listen critically I'm too tired to do anything other than kick back and sink into the sound. This will change at some point but not for the next decade :)
 
At the same time, any such performance anxiety/etc is a system noise. And may be much of what does differentiate between the time and numbers of testers needed (citing Harman's work) to determine listener preferences*. It's really important to say "it might be there, but it's below our testing resolution". This is especially the case when we're talking about these kinds extremely subtle things that are, by nature of their subtlety, also marginal in their importance to ultimate endpoints of "enjoyment". (Quotations solely to emphasize this is a rabbit hole)

Which is to give context that talking about issues that are in the threshold of detection by mainstream DBT (NOT NECESSARILY ABX) are pretty far down the totem pole of importance, well behind in-room response (and resonances). Not to discount them, but also, let's not place them falsely on a pedestal.
 
Yet so many stories abound about professional classical musicians not being bothered about having a nice stereo because they can't really enjoy the music as they are listening to the performance and its such a poor facsimile of being on stage in the midst of it all. These may be totally apocryphal but there must be enough people on here with connections for at least a basic straw poll.

A player in the midst of the orchestra is going to be getting an entirely different audio experience to the audience. I don't think this is the reason. https://vimeo.com/105956513
 
At the same time, any such performance anxiety/etc is a system noise. And may be much of what does differentiate between the time and numbers of testers needed (citing Harman's work) to determine listener preferences*. It's really important to say "it might be there, but it's below our testing resolution". This is especially the case when we're talking about these kinds extremely subtle things that are, by nature of their subtlety, also marginal in their importance to ultimate endpoints of "enjoyment". (Quotations solely to emphasize this is a rabbit hole)

Which is to give context that talking about issues that are in the threshold of detection by mainstream DBT (NOT NECESSARILY ABX) are pretty far down the totem pole of importance, well behind in-room response (and resonances). Not to discount them, but also, let's not place them falsely on a pedestal.

I sure hope listening is of the near-field type, minimally influenced by room acoustics, but starting with a reasonably good room.

As far as anxiety as a factor, some people complain about it, so it seems to me that makes it worthy of being investigated to determine its significance. Deciding to ignore a complaint by test subjects without looking into it would seem unwise.
 
Good point Scott, do you think they are the wrong value? I did NOT design this input stage, the Taiwanese did. I just went along with them. Would another cap be perhaps better? Maybe we should measure it.

If someone else did the design the first thing is to ask why there is such a small cap in that position. Maybe it's just a placeholder and they didn't need to find an optimum value. I just think that in a very low frequency servo adding a 2MHz time constant seems strange. I've had audio circuits sound fine even though they were oscillating at 60MHz, sometimes the opposite is true.
 
Okay, that's you. But, some people are different and do get nervous. People really do vary a lot in how they react to different situations.

That's all well and good but you need to clarify why participating in a simple listening test would cause anxiety. Someone says here are two amplifiers one costs $200 one costs $10000 tell the difference. You have to realize that this by itself eliminates any possibility of any objective result.
 
Status
Not open for further replies.