Don't know, but isn't the fifth THD plus noise? I don't like the last even though it is very popular.
The result is THD + Noise, the plotting method is to sum everything other than the signal which gives that result. However the common shorthand is to call it a THD plot.
Hint, when you actually listen to an amplifier what is the actual output level?
Thanks jn for that (I'm glad I noticed you answered already).
BTW, the schematic for the 3554 on the Burr-Brown datasheet I linked to appears to be at variance with the specifications, which suggest it has JFETs in the front end (the amount of bias current and its temperature dependence is a giveaway).
Brad Wood
Thanks for the explanation. At least I know what to look into when I need to find further information. Coz it is hard for me to differentiate between "chip" and "chip plus". It shouldn't be just about size, but should be about different technology that make chips a different creature than discrete. It reminds me of STK "chips" (so that's why old STK documentation used the "hybrid" and "module" terminology in the datasheet).
From the looks of the schematic I saw yesterday and mysteriously appears to be inaccessible today, the drafting person lacked a symbol for JFETs and substituted bipolars. If the four input bipolars are changed to JFETs everything else looks pretty straightforward, indeed pretty boring.
Of course the part has been long discontinued.
He is a theorist.
Not an experimentalist.
I don't mingle with the theorists.
A theorist is someone who looks at hardware and says. WHA??
An experimentalist is someone who breaks the hardware and says...WHA?
jn
Of course the arch theoretician Pauli was known to cause hardware to break merely by being in the vicinity.
I notice that things have gotten quiet, lately. '-) I presume that ending speculation tends to do that.
I am very surprised that many here did not jump on the idea of making a simple dual IC line amp, and directly comparing it with anything else available or perhaps possible.
I am constantly confronted by my critics that this is 'reality' and that my 'extreme' efforts are just a waste of time, but I haven't gotten any takers as of yet.
Of course, anybody can take just about any line amp and compare it to another line amp and get a NULL result. Unfortunately, I must insist on an 'open' test, at least a defined A or B, is necessary to hear any difference. Still, A and B could be randomly selected, even by computer, it is just knowing that A is always A, and B is always B when making the comparison, that is important to me.
I think that people should put their efforts into what they believe, rather than putting down the beliefs of others. Then, relatively neutral third parties can decide if one is better than another, to eliminate self bias. This is how we do it in the audio industry, at least 'ideally'.
I am very surprised that many here did not jump on the idea of making a simple dual IC line amp, and directly comparing it with anything else available or perhaps possible.
I am constantly confronted by my critics that this is 'reality' and that my 'extreme' efforts are just a waste of time, but I haven't gotten any takers as of yet.
Of course, anybody can take just about any line amp and compare it to another line amp and get a NULL result. Unfortunately, I must insist on an 'open' test, at least a defined A or B, is necessary to hear any difference. Still, A and B could be randomly selected, even by computer, it is just knowing that A is always A, and B is always B when making the comparison, that is important to me.
I think that people should put their efforts into what they believe, rather than putting down the beliefs of others. Then, relatively neutral third parties can decide if one is better than another, to eliminate self bias. This is how we do it in the audio industry, at least 'ideally'.
John, as i said, i compare my preamps with a strait wire. it would be a nonsense to compare blue and green. Really, i do not need any blind procedure, i'm looking for trouble, not for pride. Of course this is possible when no added hiss, but i'm dedicated with digital. I'm not listening for *sound quality*, I'im listening to differences. If any, i try something else. As is said, i'm not able to hear noticeable difference between my preamp and a wire, why i should look for something else ?
Does-it make sens to you ?
BTW, i never read "reviews", and i'm very suspicious (as you had noticed) about my own *opinions*, and *opinions* of others as well. But when, after many experiences, always correlated, i found something who can make myself a rule, i share-it.
[edit] When comparing to differences, there is, sometimes subtle ones, you need to compare and compare again... When it is so, i do not insist, and consider-it as a no-difference.
Does-it make sens to you ?
BTW, i never read "reviews", and i'm very suspicious (as you had noticed) about my own *opinions*, and *opinions* of others as well. But when, after many experiences, always correlated, i found something who can make myself a rule, i share-it.
[edit] When comparing to differences, there is, sometimes subtle ones, you need to compare and compare again... When it is so, i do not insist, and consider-it as a no-difference.
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John,
As one of the neutral figures here I follow what you are saying. At the same time it would appear that the discrete designer should have some real advantage as you can select every single individual component and also make any minor circuit corrections that you may choose to implement While the IC component direction would have the advantage of physical size of a circuit and perhaps more current investment in R&D, it appears that not much of any of that would be directed at the audio industry per say. A/D and D/A converters perhaps being the exception. I would imagine that a fair minded designer would probably use a combination of both approaches to achieve their ultimate designs.
As one of the neutral figures here I follow what you are saying. At the same time it would appear that the discrete designer should have some real advantage as you can select every single individual component and also make any minor circuit corrections that you may choose to implement While the IC component direction would have the advantage of physical size of a circuit and perhaps more current investment in R&D, it appears that not much of any of that would be directed at the audio industry per say. A/D and D/A converters perhaps being the exception. I would imagine that a fair minded designer would probably use a combination of both approaches to achieve their ultimate designs.
Not so sure: We had tried this joke near a well known reviewer, during the listening session with some real other preamps.
The wire was not the winner, according to his notes
We were not in so good relationship with him, after having revealed the trickery
but "have come to accept this" on the bais of 20 yr old op amp comparisons really isn't sufficient when the tech is a moving target - monolithic in particular has really stepped up in process and design in the past decade or so - but when you mention IC's you only talk much older parts
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