Conrad Hoffman said:
One thing that I wish reviewers would do is to measure the frequency response of the amplifier at the speaker terminals of the speakers they are listening to. Never underestimate the change in sound or soundstage that a small difference in frequency response can make.
The closest we come to this is JA's frequency response curves into a common simulated speaker load. I'd like to see it with THE speaker being listened to.
Cheers,
Bob
Stereophile mag Oct 2007
"I wonder how much effort is spent hand picking the OP-Amps?
Niose?
Bandwidth?
etc.
Same for resistors & caps.
0.1% matching tolerance?"
Add to the list" Rail to Rail Performance" audible characteristics of chosen resistors, type of, and manufacturer of passive components in their respective locations"
My apologies for taking this thread further off the topic.However, it should not have been necessary to try and redress the lack of balance of the original post. I hope that some members at least, now have some inkling of the hidden costs involved in getting a product to market.
Thank you Sy and others for your patience and tolerance.
SandyK
"I wonder how much effort is spent hand picking the OP-Amps?
Niose?
Bandwidth?
etc.
Same for resistors & caps.
0.1% matching tolerance?"
Add to the list" Rail to Rail Performance" audible characteristics of chosen resistors, type of, and manufacturer of passive components in their respective locations"
My apologies for taking this thread further off the topic.However, it should not have been necessary to try and redress the lack of balance of the original post. I hope that some members at least, now have some inkling of the hidden costs involved in getting a product to market.
Thank you Sy and others for your patience and tolerance.
SandyK
john curl said:
This is why I always attach conditionals to things. Recall I said 'for the most part' about the ear ignoring the back wave. We still hear it, but not remotely like we weight the leading edge via our hearing.
We all..well...not all realize this...there is still many a horn fanatic. My business partner and I have analysed the 'horn' for about 10-12 years and are about to mount an attack on it's issues. Gonna fix that puppy.
As you well know, we try to help our fellow audio dudes on their journey..but we reach a point where we say too much and it affects our ability to make an income; to put bread on the table. The post on hearing vs measurment is one of those. I may in the future regret posting it. For it is definitely true.
When you have a certain level of intelligence, or capacity, or a 'level of existence' people you can relate to can sometimes be few and far between. Hell no - they most definitely are few and far between.
I have been accused of making friends 'uncomfortable' when in line-ups at the theater or the like. I can get verbal or loud, in some ways. Saying seemingly strange things, or letting out some strange thoughts. Strange to most.
Every now and then, when in those crowds I metaphorically scream 'MARCO!' Sometimes some other intreped soul gets it, and yells back "POLO!"..and I am given an opportunity to reach another person who is actually listening. And they..reach me.
And by fits and starts we help in the elevation of the Art, for those who are listening. We cut through the noise to find the signal.
As for IC's vs Discrete, I think that discrete is notably better, yes. But I can't design a circuit to save my life. But I can optimize it, re PS, substrates, material junctions, noise control, vibration, layout, fields, and all of that concerning the materials science, down to the wave/particle level. I do it strictly on intuition and it has not failed me yet.
I will say a thing that will cause a ruckus: I do it by visualizing the complex aspects of atomic structures (wave/particle/vortex, etc) in totality. Yes, I visualize with appropriate weighting. Hollistically. A tough one for the math nerds, I know, but some can do it. I can. It's just not a common thing, is all. Took me years to build that tool, as you might imagine. To say that it is a valuble tool, would be the understatement of the century.
Has anyone actually USED these opamps?
Has anyone actually USED these National opamps? I ask because I HAVE. I built a control preamp with balanced inputs, DC coupling and a DC servo using a total of three of the duals. The input is 10K balanced unity gain differential, using resistor networks (high common mode rejection). One dual opamp has both channels running through it. For a volume control, I used a 100K cermet dual pot with a 15K resistor between its wiper to ground (approximates a log taper). The next gain stage has a non inverting gain of ten using one dual per channel. The second opamp in each chip is the servo. The circuit's frequency response is 3 db down at under 1 Hz and over 100 kHz. The output resistor is 10 ohms. The unit is powered by a pair of 15 volt three terminal regulators. I deliberately used a less then perfect power supply, because these opamps claim 120 db power supply rejection.
I have been in pro and high end audio for over 25 years. Over the years, I've owned McIntosh amps, highly modified Adcom amps and preamps, various Dynaco amps and preamps (Both tube and solid state), and about a thousand Rotels, Technics receivers, NAD integrated amps, etc. My speakers include KLH Model 9 electrostatics rebuilt by Dave Janszen, the original designer's son-with parts from his dad's new stock.
I've also owned over the years Celestion SL-700's, and on and on. Right now I have full range speakers crossed over to a supertweeter at 8000 Hz. My amp is a T amp heavily modified.
I'm telling you this so you know that I know good audio when I hear it....
These opamps are FABULOUS!!! YES, a silicon chip can sound excellent! I've heard many preamps over the years and these are among the BEST I HAVE HEARD! In many ways, they sound like nothing at all....and I mean that in the best way.
My point is this...before you trash something, TRY IT FIRST! You might be pleasently surprised!
Of course, in the subjective audio industry, politics is likely as important as sound, isn't it?
Has anyone actually USED these National opamps? I ask because I HAVE. I built a control preamp with balanced inputs, DC coupling and a DC servo using a total of three of the duals. The input is 10K balanced unity gain differential, using resistor networks (high common mode rejection). One dual opamp has both channels running through it. For a volume control, I used a 100K cermet dual pot with a 15K resistor between its wiper to ground (approximates a log taper). The next gain stage has a non inverting gain of ten using one dual per channel. The second opamp in each chip is the servo. The circuit's frequency response is 3 db down at under 1 Hz and over 100 kHz. The output resistor is 10 ohms. The unit is powered by a pair of 15 volt three terminal regulators. I deliberately used a less then perfect power supply, because these opamps claim 120 db power supply rejection.
I have been in pro and high end audio for over 25 years. Over the years, I've owned McIntosh amps, highly modified Adcom amps and preamps, various Dynaco amps and preamps (Both tube and solid state), and about a thousand Rotels, Technics receivers, NAD integrated amps, etc. My speakers include KLH Model 9 electrostatics rebuilt by Dave Janszen, the original designer's son-with parts from his dad's new stock.
I've also owned over the years Celestion SL-700's, and on and on. Right now I have full range speakers crossed over to a supertweeter at 8000 Hz. My amp is a T amp heavily modified.
I'm telling you this so you know that I know good audio when I hear it....
These opamps are FABULOUS!!! YES, a silicon chip can sound excellent! I've heard many preamps over the years and these are among the BEST I HAVE HEARD! In many ways, they sound like nothing at all....and I mean that in the best way.
My point is this...before you trash something, TRY IT FIRST! You might be pleasently surprised!
Of course, in the subjective audio industry, politics is likely as important as sound, isn't it?
SpittinLLama said:
One thing you can say is that the distortion wave shows that the amp gain is asymmetrical. The distortion wave is different for pos then for neg parts of the wave. This means mostly odd order components. Could also be an amp close to clipping, you see the same sort of thing.
I don't think any distortion shape gives a clue as to why it rises with frequency. Almost always that is because your nfb goes down with frequency.
Jan Didden
Re: Has anyone actually USED these opamps?
I use them in my DCX2496 remote volume/offset control mod kit . So far I have done 4 or 5 demo's at people's house or for friends on my own system. Without exception, the comment was that there is now much more difference between CD's that they thought were all 'pretty good'. More things heard that they were not aware of that they were on the CD.
Now, I'm firmly in the camp that if you hear a difference it must be possible to measure it. But fore this, I don't really know what to measure. I'm not comfortable with it, but I can't sweep it under the rug. There's something in those chips (and possibly in others) that give it an edge.
Jan Didden
dpuopolo said:
I use them in my DCX2496 remote volume/offset control mod kit . So far I have done 4 or 5 demo's at people's house or for friends on my own system. Without exception, the comment was that there is now much more difference between CD's that they thought were all 'pretty good'. More things heard that they were not aware of that they were on the CD.
Now, I'm firmly in the camp that if you hear a difference it must be possible to measure it. But fore this, I don't really know what to measure. I'm not comfortable with it, but I can't sweep it under the rug. There's something in those chips (and possibly in others) that give it an edge.
Jan Didden
john curl said:
John,
I suspect I can call this on-topic
. Just for the comparison here is a link to one example (of many) of what the creator of these nice phonoamps (with a price tag that so upsets labjr) says about his design:http://rockgrotto.proboards39.com/i...n=display&thread=1191476591&page=1#1191953991
Would you call that advertising?
. Cheers
Alex
He also says that a scratch sound - which comes from a mechanical pick-up, is so fast that an amp can't follow it. That's an extraordinary claim.
It's back to that tired old story of the fb that comes to late bla bla.
But maybe we need these kind of fairy tales to keep these designers occupied.
Jan Didden
It's back to that tired old story of the fb that comes to late bla bla.
But maybe we need these kind of fairy tales to keep these designers occupied.
Jan Didden
Jan, you are talking in an area that you don't understand. Back in 1978, I published mistracking artifacts out to 200KHz in an IEEE paper. I have seen 500KHz artifacts.
The reason is that the phono cartridge 'differentiates' the mechanical signal and that is what makes it so nasty. I.E. triangle waves become square waves, square waves become pulses, etc.
I have measured 5us peak periods of pulses directly from phono cartridges. That is one major reason why it is so difficult to make a good phono stage with cheap IC's.
The reason is that the phono cartridge 'differentiates' the mechanical signal and that is what makes it so nasty. I.E. triangle waves become square waves, square waves become pulses, etc.
I have measured 5us peak periods of pulses directly from phono cartridges. That is one major reason why it is so difficult to make a good phono stage with cheap IC's.
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