How do you design something for a market with the purely technical spec "it rocks"?
https://www.youtube.com/watch?v=7p3dK8PlQbc
Sorry not to have mentioned LT1361 !! The only "bad" thing is that it is a lower current device and has not an emotional midrange as AD826 and LT1358 have.
But it is definitively one of the most crystal clean, neutral, and musical opamp. Very good at input stages
In any case all the Linear Technology family 1355, 1358, 1361 and 1364 is audio superb !
Amplifier valve kits, HIFI pre-amplifiers, speaker kits, AMP Parts, upgrade components - Hifi Collective is much cheaper in my experience!
Most of the internal structures, which I note by opamps are this:
1) one voltage gain stage (mostly folded cascode) + buffer - mainly used in video op-amps
2) two voltage gain stages (LTP + VAS with internal and/or external Cdom) + buffer - mainly used in typical audio op-amps
(AD797 and OPA604/2604 are examples of exceptions - because the simplified schematics looks a lot like those from video op amps).
Concerning the sonic quality I note, that most op-amps with one internal voltage gain stage provides better results than such with two gain stages, as long the non inverted mode is in use (both RIAA and line stages applications).
But what happens at listening tests by using inverting mode topologies between this mentioned kinds of topologies (e.g. NE5534 vs. AD829 resp. dual versions NE5532 vs. AD826)? - go for example to the circuit diagrams in post from Mon Dec 16, 2013 2:14 pm under
Shunt feedback in phono preamplifiers : new topics on this forum
Thank you for advices.
And a second question: where are to filed the LME-Series from TI - are there one or two voltage gain stages internal in use - ? go to
http://www.diyaudio.com/forums/soli...-lm-4562-lme-49710-49720-a-2.html#post4825374
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As I have probably said earlier, some 50 pages ago perhaps, the best I have managed to find so far is the LM6172. It's really good to see there are some people who rate that who also rate other ones as well. None of which I seem to have tried incidentally, though I have done the usual rounds of LM4562, OPA2604, and some of the newer LM 49xxx.
I love LT products, but they are so damned expensive. Are any of the ones mentioned not expensive?
Has anyone tried the single LM6171. I don't think there's anything additional you can get from the pins, but I may be wrong, but perhaps just having separate decoupling caps for each stage might help. Incidentally, FWIW, I tend to use much larger than the std 100nf.
I love LT products, but they are so damned expensive. Are any of the ones mentioned not expensive?
Has anyone tried the single LM6171. I don't think there's anything additional you can get from the pins, but I may be wrong, but perhaps just having separate decoupling caps for each stage might help. Incidentally, FWIW, I tend to use much larger than the std 100nf.
I'm liking the LME49990 and OPA1642 for line stage work. But op-amp IC sonics are so dependent upon circuit that it's hard to generalize. I've heard video op-amps that sound great in certain audio circuits, and the same video amps that sound horrid in other audio circuits. No cookbook answers here.
With such wide bandwidth devices, also use a parallel 0.01uF, mounted very close to the supply pin,
with a ground plane.
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H.Ott tells us to select the package that achieves your requiement for low enough impedance at HF. Then select the highest capacitance in that package.
So, having read through all 227 pages (yes my life really is that meaningless), what I get is:
1. A list of about 50 op-amps that is everyone's favourite, all different of course.
2. Op-amp X is better than op-amp Y/op-amp Y is better than op-amp X - for X and Y read every op-amp.
Of course there is no 'best' sounding op-amp. It all depends on what and where the op-amp is used for, how it's applied and the supporting circuitry (power supplies, regulators, passive components) etc. etc.
Thanks for wasting a week of my life on and off. I guess should have known what the outcome would be when I started!
1. A list of about 50 op-amps that is everyone's favourite, all different of course.
2. Op-amp X is better than op-amp Y/op-amp Y is better than op-amp X - for X and Y read every op-amp.
Of course there is no 'best' sounding op-amp. It all depends on what and where the op-amp is used for, how it's applied and the supporting circuitry (power supplies, regulators, passive components) etc. etc.
Thanks for wasting a week of my life on and off. I guess should have known what the outcome would be when I started!
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The reason TI shut down the LME parts is because they already owned BurrBrown and felt the National LME parts were a conflict with the BurrBrown parts. Also they had rules about parts selling 1 million pcs a year and the LME parts did not meet that requirement. The entire audio group at National/TI in Santa Clara are gone now. Lastly the LME parts were made on a special process and TI did not want to support that process and it was shut down. The great LME parts are going to be unobtainium very soon. (10 years of work and tens of millions of dollars flushed by TI. Buy your biggest competitor for 6.5 billion, because you have billions in the bank making low interest, and then shut down most of the company and sell off the assets. Sound Familiar?)
I have enough of all the LME parts for my personal projects except for the LME49811's. I need a few more of those for spares for my 0.0005% THD+N 160W mono power amps. I have enough LM4702's and they are nearly as good as the LME49811's. Same part actually with the mono LME49811's being a stereo LM4702 cut in 1/2...literally along with an internal IC layout change on the input stage of the LME49811's to slightly improve low level performance! This change was suggested by the late/Great Bob Pease! (I actually specified the LME49811's.)
audioman54 / Mark
I have enough of all the LME parts for my personal projects except for the LME49811's. I need a few more of those for spares for my 0.0005% THD+N 160W mono power amps. I have enough LM4702's and they are nearly as good as the LME49811's. Same part actually with the mono LME49811's being a stereo LM4702 cut in 1/2...literally along with an internal IC layout change on the input stage of the LME49811's to slightly improve low level performance! This change was suggested by the late/Great Bob Pease! (I actually specified the LME49811's.)
audioman54 / Mark
Hello Mark,
It's very sad to see what has happened to the old Audio Group at National. I do not see the changes as good for anyone except the TI stockholders. Am I correct in thinking that TI has changed their mind about dumping the LM4562 part?
Mark
It is truly a shame what happened with the National audio group and that the amateur DIY audio enthusiast won't have a choice between the LME and OPA types any more, but the OPAs do have tremendous specs and, in your opinion, is there really any significant difference in sound quality between the two types?
What OPA op-amps should we be looking at for highest performance audio, if any? The OPA1622 catches my eye.
It is truly a shame what happened with the National audio group and that the amateur DIY audio enthusiast won't have a choice between the LME and OPA types any more, but the OPAs do have tremendous specs and, in your opinion, is there really any significant difference in sound quality between the two types?
What OPA op-amps should we be looking at for highest performance audio, if any? The OPA1622 catches my eye.
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I am sure many of you would have come across or read this blogs. I am not an expert by any stretch of the imagination, yet he makes a lot a sense to me!
NwAvGuy: Op Amps: Myths & Facts
http://nwavguy.blogspot.no/2011/05/subjective-vs-objective-debate.html
NwAvGuy: Op Amps: Myths & Facts
http://nwavguy.blogspot.no/2011/05/subjective-vs-objective-debate.html
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In Italy the magazine "Nuova Elettronica" writing for us and for the school by selling kits since 1969 failed partly because there are more components to be mounted to the naked eye, but let's face it, with the advent of the Chinese many things have changed .. .what will happen to our electronic youth? This is progress.
For me are fine all the op-amp designed for audio, important it is the layout and respect the datasheet, but the problem is limited to the rails + -18V for preamp which requires, in order to respect the dynamics undistorted, amplifier with gain> = x40
For me are fine all the op-amp designed for audio, important it is the layout and respect the datasheet, but the problem is limited to the rails + -18V for preamp which requires, in order to respect the dynamics undistorted, amplifier with gain> = x40
I was opening another thread, when I found this one.
I've been looking at several solid state preamp schematics, both for line and RIAA, in discrete or opamp versions. DAC outputs too.
Building discrete projects became very difficult, impossible if it involves mating N and P FETs.
Several ICs that were considered good sounding, like the LME49720 or LM49990 have been discontinued.
Newer options have not been consistently tested by diyers, so they are a bit of a question mark, to me at least.
But I found one old chip that was praised some years ago: THS4031 and THS4032.
http://www.ti.com/lit/ds/symlink/ths4031.pdf
This thread grew into a large number of pages, so I wonder if there have been any winners, or at least by application.
I've been looking at several solid state preamp schematics, both for line and RIAA, in discrete or opamp versions. DAC outputs too.
Building discrete projects became very difficult, impossible if it involves mating N and P FETs.
Several ICs that were considered good sounding, like the LME49720 or LM49990 have been discontinued.
Newer options have not been consistently tested by diyers, so they are a bit of a question mark, to me at least.
But I found one old chip that was praised some years ago: THS4031 and THS4032.
http://www.ti.com/lit/ds/symlink/ths4031.pdf
This thread grew into a large number of pages, so I wonder if there have been any winners, or at least by application.