AD797 now sounds like it should - Page 3

There is no such thing as a "house sound" associated with a particular semiconductor brand. Each company, be it TI/Burr-Brown, Analog, Linear, National, whatever., have hundreds of models of opamps, each of which are different in design, and 99% of them were not even intended for audio. Some happened to work well as audio amps. If a few opamps from a particular company sounded alike, it's pure coincidence, not by design. I am sure if the engineers at Analog or TI were reading this they would be quite amused about the "house sound" theory.

My and amb's point, though, is that this is a false generalisation. Someone who would rely upon this generalisation would be misled about the nature of each company's products. If you are encountering a house sound, it is probably due to sampling error or cognitive bias (or both).

Aside from this, it seems as though people rather casually introduce various op-amps to a circuit and then pass judgment based upon this. High speed op-amps in particular need a substantial body of supporting topology in order to function properly. If you do not have this, you will get distortion; sometimes a lot of it.

Such errors don't have to be due to the words of others. However, it sounds like you're going into each of your trials with some notion of house sound, and that could bias your results. Secondly, you mentioned you were looking at what was noted for audio use either explicitly or by what people used, which points towards sampling bias.

I'm ear trained for very subtle changes in response, including distortion spectra, since I helped tune psy models as well as have worked on other audio-related projects. I doubt that's the problem here. If you have a wide bandwidth spectrum analyser, or perhaps a scope if you know how to use it properly, you can see for yourself that improper implementation leads to out-of-spec performance. Obtaining optimum performance from a particular chip sometimes comes down to a case-by-case basis rather than having a generic circuit that you can simply plug everything into. Furthermore, most op-amps are not designed to drive a load such as a headphone directly, and the result can be a rather large rise in distortion.

You're wedded to ungrounded notions of "house sound" and other subjectivist traits of inherent character in your descriptions of op-amps, and that seems to be encumbering your ability to approach this issue objectively. Responding to such comments with a critical approach and a concern for proper implementation and optimisation is not somehow deprived and obtuse to the concerns of subjective response.

Hmmm...... I've found what seems to be cleaner sound with more resolution with the LM4562 as compared to the NE5532. In comparison, the 5532 seems a bit lacking in detail in the highs, along with greater DC offset. LM4562 seems better in this regard.....

It seems like what's really going on here is that you're unhappy that I criticised your evaluative methodology, and so are responding by insinuating I simply lack the ability to make relevant analysis of the suitability of one chip or another for audio purposes in order to argue that somehow your methodology is sound and your evaluations accurate. This is a pretty unconvincing argument, overall, and is mostly just an ad hominem argument instead of a substantive defense of your methodology and does very little to address the issue of accuracy. I'm not sure what to make of your tangent on subjectivity and individuality but perhaps you dislike this 'scientific' approach because it appears to contain underlying deterministic elements which, when fused with a sensitivity to subjective performance, undermines an idea of people carrying individual, exclusive, and perhaps unique ownership of their preferences. Since what you're posting is almost patently incoherent at times, it's rather difficult to be sure this is the case, but that's the impression you've given me.

Science is fundamentally about mastery of the empirical universe, which includes subjective phenomena. Thus an analytical approach that involves science is relevant on the issue of subjective response. It's a matter of abstracting it to analysable data which can be used to obtain the desired results, not a matter of substituting something akin to my written response to you for the somatic elements of my hearing when I listen to music. It is simply not useful data or discourse for me to bother with using unclear subjectivist terms to describe amplifier performance, nor is it particularly useful or productive to act as though my senses will somehow transcend the physical limitations of these devices such that I can sense some (fictitious) essential character and render forth a description for all to bare witness to.

Thus, it remains the case that op-amps are sensitive devices, and some of them may have their performance shifted dramatically by environmental factors that seem negligible, or simply don't occur to the user, and may not necessarily impact the performance so dramatically with other chips. Responding by telling me that you're just relaying what you're hearing and that you have confidence in the designs of the Xenos and Go-Vibe products doesn't change that and, looking at those respective designs, doesn't provide a particularly compelling case that this issue is of negligble relevance. Responding by telling me I'm being too analytical and insinuating that I'm completely obtuse to the matter at hand simply insults the integrity of our discussion and essentially forces us to discuss irrelevant matters.

The Ib on the 4562 is lower, so sure you'd probably get lower offset. The NE5532 is quirkier to work with than the 4562 and is more sensitive to your decoupling/bypassing configuration, so it may be of some benefit to check that first before passing final judgment. Also, which 5532 did you use? There are a few variants out there and, due to some differences in the manufacturing process, performance is shifted somewhat as a result. I've found the TI part to work the best, although I know a lot of people seem to like the old Philips/Signetics (which I have, but have found kind of fuzzy sounding; possibly due to poor settling characteristics onset by a less refined manufacture process). Overall, though, I'm still mostly undecided between the 5532 and 4562 on which sounds better.

Well, I guess a muddled reference to dialectic along with a misunderstanding of what constitutes 'empirical universe' is as good a way as any to end the conversation.

The 5532s in my possession are a Signetics NE5532 from my NAD 3150 integrated amplifier and an old Exar XR5532 which I had lying around. From what I recall, neither seems to have the openness of the LM4562, but it has been a while since I have given them a critical listen. Also, note that I've been using them in either the preamp stage of my NAD or in my Eden WT-500 bass amplifier, NOT in a headphone amplifier, although I have made sure to employ careful decoupling in both circuits. I'm planning to build a variant of the CMOY sometime in the near-future. The particular applications under study may explain some of the differences I'm hearing....

Ah, okay. Your description definitely made me wonder if you were using the Signetics chips; I'd probably describe them similarly. I mostly compared the chips in an LPF or buffer stage, so I think we're getting fairly similar circumstances in our comparisons. I didn't get the opportunity to compare the TI and Signetics NE5532s as much as I would have liked, but I did compare the respective 5534s considerably, and found that the differences appeared to be of the same nature. The Signetics are less clear, have a narrower soundstage, and an overall warmer character. When I ran them on an analyser, I did notice more distortion in the Signetics overall.

'Empirical universe' refers to the sum total of those things observable, which includes things such as "this sounds like ____ to me." I called your reference muddled because that's essentially the concept you're describing, but you chose to use a circuitous and ultimately unclear method of conveying it. Secondly, just because I don't endorse your view of the issue doesn't mean I don't understand it. On the contrary, I understand it, and find it lacking. Mi spiace che non mi capisce....;D

Synaethesia is the misexcitement of one sense in place of or simultaneous to the excitement of another. e.g., synthesis of aesthetes, or synaesthesia. That really isn't relevant here, and you've done very little to show that I somehow lack the capacity to do useful analysis of subjective response in amplifier performance other than a bunch of hand-waving and digression. Giving me watered down greek, cartesian, and existentialist philosophy along with ad hominem arguments doesn't make the problem go away; it just makes our conversation look silly and takes up a bunch of space with irrelevant banter.

Anyhow, I'm not going to subject the DIY forum to more of this. I get it; you think I'm somehow obtuse to the fundamental nature of audio, and that's your defense to your test methodology and your results. Have at it; buona notte.

I know it's not easy to satisfy myself and I have to admit that the AD797 is a very good op-amp that I can't stand. It's the same case as with the OPA637 - it's very good but there is something wrong and frustrating in the sound. The OPA637 lacks attack, sounds begin to slow, with compressed impact. In the AD797 I hear that lower treble glaze, maybe it helps for rock but it's too obvious and pronounced that I perceive it as a residual addition to the sound which I would like to get rid of but I cannot. I don't think it's due to stability issues because no symptoms of that have appeared in my circuit - normal power consuption and no weird behaviors while turning the volume knob or plugging the headphones.
As I mostly agree with the description comparing the AD797 to the AD8397 (which I refused to use any more many months ago), I have to say that there are op-amps that in spite of being audibly imperfect, they are likeable, i.e. AD825 single or AD8022 dual, and on the other side, there are chips being almost perfect, with one but nasty imperfection. Maybe it's because this imperfection is not well hidden behind the others but I'd rather say this is more because of their inacceptability to a certain individual like me. Ending this elaborate write-up, I think the OPA211 is worth direct comparison with the AD797, they are not far from each other IMHO, with the OPA211 providing better soundstage and no artificial treble shine.

I tried to try yesterday, but IE7 in my office doesn't work with the Linear Shopping Basket correctly. It does not update. I have to remember ordering the LT1364's when at home where I have more internet browser options and access rights.