John Curl's Blowtorch preamplifier part II

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Max,
I have heard many systems that get it about right but it is the finer details that are just missing that make all the difference to me. The sound of fingers sliding on the fingerboard of a guitar, the sound of a squeaky pedal on a piano, or even being able to tell that the drummer is using a set of brushes on a cymbal instead of a generic high frequency sound. Those finer details are the things that we often don't notice are missing until you hear a track that you know and then you hear things never heard or noticed before.

That isn't going to happen with a mediocre speaker system, definitely not happening on a PC speaker with a cheap chip amp implementation.
 
So I'm trying to wrap my head around this. Do I have it right that a CD based system is being optimized for a Bruce Springsteen CD? And if so; What has been done with the DAC clocking?
In that particular case, nothing directly - I don't work on fixing what may be the problem, I rely on experience, from what has been effective in the past, and apply that. If the sum of all the improvements to date is enough to give satisfying sound then I'll leave it at that - with the CD system, which in fact was a throwaway HT all-in-one, the main efforts were directed towards ensuring very clean power was being fed to the sub-systems in the main box - this did the job well enough to prove the point, so I didn't go further.

If the Springsteen CD works well then everything works well - I can immediately put on straight afterwards a Beethoven String Quartet, or a Maria Callas performance, and they work beautifully - the system is not tuned or prettied up to work for some genre, rather it has the bugs removed which stop all the more 'difficult' recordings coming across well.
 
Max,
I have heard many systems that get it about right but it is the finer details that are just missing that make all the difference to me. The sound of fingers sliding on the fingerboard of a guitar, the sound of a squeaky pedal on a piano, or even being able to tell that the drummer is using a set of brushes on a cymbal instead of a generic high frequency sound. Those finer details are the things that we often don't notice are missing until you hear a track that you know and then you hear things never heard or noticed before.

That isn't going to happen with a mediocre speaker system, definitely not happening on a PC speaker with a cheap chip amp implementation.
Fortunately, this is largely not the case. I say largely, because the PC speakers hit the limits of their tiny power supply fairly early, there are volume issues here; where you are correct is that the cheap components fail to convince normally because they require too much warm up time - pricey gear should at their full potential quality within, say, 5 minutes from cold startup.

That fine detail you mention is trivial to pick up when a system is in its stride, and cheap speakers have no trouble doing it, if all the right steps have been taken beforehand.

As regards 'correcting' the music that can never be done, but what can be achieved is for every last detail that's in the recording be passed across to the listener with minimal damage. Then, the 'magic' of our mind's signal processing ability can take over, and effectively discard the grunge of the recording, we listen through the muck and 'hear' the music being played. A collection of Robert Johnson recordings on CD is pretty close to as bad as it gets, yet when all is in alignment there's a real man playing a guitar in front of you, you can feel his presence in the room ...
 
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I have maintained this same thought/conclusion for a very long time.
I find it is the the novice/inexperienced audiophile and some reviewers that respond to this false detail in positive ways.

Dan.
Yes, detail should just be there without drawing attention to itself. Somewhat like good bass and "bad" bass - everyone knows the latter, like a kid jumping up and down on the bed yelling, "Look at me, look at me!!" - good bass completely integrates with the rest of the picture, you only notice its positive benefit by the impact of its sudden absence.

The absence of detail, though, has a somewhat more serious effect, it lends a cartoonish, 2 dimensional, unconvincing patina to the sound - one can't quite take the sound you're listening to fully seriously ...
 
Max,
I have heard many systems that get it about right but it is the finer details that are just missing that make all the difference to me. The sound of fingers sliding on the fingerboard of a guitar, the sound of a squeaky pedal on a piano, or even being able to tell that the drummer is using a set of brushes on a cymbal instead of a generic high frequency sound. Those finer details are the things that we often don't notice are missing until you hear a track that you know and then you hear things never heard or noticed before.
It's those fine details like brushes, fingers sliding etc that some systems can easily over emphasize.....and to me that gets boring within about one minute.

Emphasis means masking....reduce the higher harmonics, and get the ratios right, and that fine detail just pops out of the air, and clean, and without drawing undue attention.
My ears can pick up undue emphasis from about a mile away.

That isn't going to happen with a mediocre speaker system, definitely not happening on a PC speaker with a cheap chip amp implementation.
Are Stax SR-X Mk3's good enough ? ;).

Dan.
 
Yes, detail should just be there without drawing attention to itself. .......The absence of detail, though, has a somewhat more serious effect, it lends a cartoonish, 2 dimensional, unconvincing patina to the sound - one can't quite take the sound you're listening to fully seriously ...
Yes, masking (distortions) reduces depth information detail, and renders depth information uncertain.
Very low frequency noise does this too.

Dan.
 
Stax are in another league compared to most cheap 50 cent speakers used in most PC speakers. All you need with those is a nice bass speaker for the body sensations!
Haha, yeah, I have a bass thumper that I can attach to my listening chair.
One mounted under each of the front sets of a Land Cruiser is a lot of fun.

The Stax can go seriously loud, and do provide a good amount of physical bass sensation, but not the same as proper, in room bass of course.

Dan.
 
Kinda reminds me of the Arye V3 was it? And others. Lookin at the pics...
English would have been nice :D

It is similar, not same. There is not much to 'investigate', the best in this case is complete symmetry (with complementary-differential input) of both input and output to get distortion cancellation and PSU residuals cancellation. Balanced output with speaker not referred to ground brings about 30dB better PSR compared to speaker output with one terminal grounded, not many people probably realize this immediately. One have to design, build and understand.
Someone mentioned a 'toy', yes this is a toy, not meant to be produced in more pieces. And I like this toy very much :D.
We are in a BT thread, and there is a strong similarity as well, but at power level.
 
Thanks

And it is completely stable into any load with no compensation ?

I have the feeling you like how this amp's performs . . . any thoughts about it's noise levels ?

I would be tempted to set the gain about 23db . . . would you envisage any problems with this ?

edit - I wonder how it compares to the JLH Simple class A you revisited a few years ago
 
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It is completely stable to any load you may imagine. No feedback power amplifier I have ever built was as stable as this one. Attached is step response to 6.8ohm + 1uF in parallel. Noise is not very low because of input MOSFETs, but they are operated at quite high idle current. S/N = -86dB/2.83Vrms unweighted, over 20Hz - 20kHz bandwidth. The noise bottom is similar to 1/f.
 

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Several years ago Charles Hansen was posting quite a lot on this forum about the merits of amps without overall feedback. He stated at one time that from his view point it was simply not possible to build amps with overall feedback that sounded as good as amps with without it.

Being of a stubborn & argumentative disposition I immediately decided to embark on a mission to design & build a great sounding amp with global feedback - it's taken me a long time to ( more or less ) finish this project and I am not dis-satisfied with the results.

However, now I am becoming curious to check out how green the grass is on the other side of the fence.

:)
 
Crareful with phrasing

Max,
I have heard many systems that get it about right but it is the finer details that are just missing that make all the difference to me. The sound of fingers sliding on the fingerboard of a guitar, the sound of a squeaky pedal on a piano, or even being able to tell that the drummer is using a set of brushes on a cymbal instead of a generic high frequency sound. Those finer details are the things that we often don't notice are missing until you hear a track that you know and then you hear things never heard or noticed before.

That isn't going to happen with a mediocre speaker system, definitely not happening on a PC speaker with a cheap chip amp implementation.

Might want to replace the royal "We" with "I" here. I, among other things, cannot listen seriously to music without hearing the brush of a cymbal, or the squeak of fingers on a fretboard, or the slap of popping strings in funk, or the pages being turned during orchestral music, etc. I recall a colleague being baffled that I identified the low frequency rumble of passing trucks in an orchestral favorite of his on an old Deutsche Gramophone vinyl from 40 years ago. He asked "Just what kind of speakers do you have??" I considered it quite a compliment, especially since he was, at the time, 40 years ago, my boss.

His wife was an accomplished NYC operatic diva as well, and he is a respected EE in the uber sensitive realm of detecting sub-millimetre signatures of distant radio waves at signal levels well below anything being discussed in this thread. He's currently supporting ALMA development.

Unless a system resolves these aspects, I consider it mediocre and I, for at least 40 years, have had systems capable of reproducing these subtle cues accurately.

John L.
 
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