[sdiy] Discrete Op Amps

[cheater00 cheater00]

My guesses are:
1. Many people know op amps better than an equivalent sort of circuit with
transistors etc and so stick to them
2. It's easier to use a ready building block than to design your own
3. End users want to use a different character part in an existing product,
or manufacturers want to do the same when producing simple clones

On Mon, 1 May 2017 14:01 David Moylan, <dave at westphila.net> wrote:

> I agree with the BS comment.  I doubt the gain "per stage" is lower.
> With current source loading etc. gains per stage can be very high.  I
> think most off the shelf opamps would beat these discrete opamps in
> measured specs for what opamps are supposed to be.  The most obvious
> characteristic is massive open loop gain (which usually gets assumed to
> be infinite in the equations).
>
> Where typical IC opamps may _potentially_ be inferior for audio is most
> likely in the type of distortion and the transition from clean to
> overdrive.  The discretes will probably have more baseline distortion.
> That alone might make listeners like them (dependent on the level).  I
> would expect they would have lower open loop gain, softer transition to
> overdrive, require less feedback for equivalent gain, etc.
>
> The whole thing is very similar to the tube/transistor debate.  I think
> results would be very dependent on the circuit around the opamps and I
> don't think the claims should be taken at face value.  I'm a firm
> believer that the only valid tests are double blind listening tests.  Do
> you think you could tell the difference in the same circuit?
>
> To me, if you don't like the massive gain plus feedback topology that
> opamps require why not just design discrete stages to provide gain/drive
> you need?
>
>
> On 04/30/2017 01:06 PM, cheater00 cheater00 wrote:
> > Every load of bullshit starts as truth that gets twisted and facsimiled.
> > So let's pick out what might be true.
> >
> > He says that the single transistors in a monolithic IC op amp can
> > dissipate much less, so their gain is lower, and therefore there must be
> > many more stages. Can this be true?
> >
> > My guess is also that control (feedback) topology ends up being much
> > more complicated, resulting in less pleasant edge cases (ie what happens
> > when the op amp reaches an unusual or extreme state). Is feedback
> > topology a large issue in op amps like it is in amplifier circuits? Does
> > using more stages make this problem bigger?
> >
> >
> > On Thu, 20 Apr 2017 20:47 Mike HEQX, <mike at heqx.com
> > <mailto:mike at heqx.com>> wrote:
> >
> >     https://www.youtube.com/watch?v=nZqmbo9CGO0
> >
> >     And this is the other character that Orange has teamed up with to
> >     market their products.
> >
> >
> >     On 4/20/2017 11:32 AM, Justin Herrmann wrote:
> >>     "Top notch, you know..."
> >>
> >>     That's all the convincing I need!
> >>
> >>     Seems legit.
> >>     On 04/20/2017, 10:16 AM Quincas Moreira <quincas at gmail.com>
> >>     <mailto:quincas at gmail.com> wrote:
> >>
> >>         oops, wrong link! i meant
> >>         this https://www.youtube.com/watch?v=tKanR1aM16I
> >>
> >>         Sent from my iPad
> >>
> >>         On Apr 20, 2017, at 9:21 AM, Elain Klopke
> >>         <functionofform at gmail.com <mailto:functionofform at gmail.com>>
> >>         wrote:
> >>
> >>             So... Quincas... you're selling the Tsunami module for $43
> >>             a pop? ;P
> >>
> >>             On Thu, Apr 20, 2017 at 9:07 AM, Quincas Moreira
> >>             <quincas at gmail.com <mailto:quincas at gmail.com>> wrote:
> >>
> >>                 this showed up on youtube today... Orange amps guy
> >>                 selling snakeoil for 43 bucks a pop...
> >>                 https://youtu.be/wulg6GZj6oE
> >>
> >>                 Sent from my iPad
> >>
> >>                 On Apr 13, 2017, at 8:56 AM, Phillip Harbison
> >>                 <alvitar at xavax.com <mailto:alvitar at xavax.com>> wrote:
> >>
> >>                     Quincas Moreira wrote:
> >>
> >>                         I like them, I cannot lie
> >>
> >>                         > There's a big BUT however:
> >>
> >>
> >>                     I can't deny. ;)
> >>
> >>                     --
> >>                     Phil Harbison
> >>
> >>
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> >>
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> >>
> >>
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