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[volki]

I just went through most of the "ICs kill music" and the "addendum" threads... which do contain interesting contributions from both "camps" - but if you really look at it, the question regarding the sonics of IC circuits with regard to their actual electronical properties hasn't been thoroughly addressed after all, now has it? Either you get opinions based on subjective experience, or, when expressed in a more objective manner, they stop right where things would actually get interesting - by which I mean details (but really EE details) regarding the electronic performance of different types of circuits with respect to nonlinear distortion.

Here and in other forums you keep reading posts that global  negative feedback (NFB), especially applied in high amounts, would lessen the original fine / detail information of sound. Sometimes there is an attempt to back the claim up by stating that the distortion-compensating effect of NFB weren't sufficiently precise due to the signal's transit time through an amp stage or block; as a result, the feedback from the output supposedtly arrives at the input too late. Thus, with increased amount of NFB, the effect is supposed to get worse.

Now, (with historical exceptions) the transit time through transistor stages alone would be orders of magnitude too short as to even affect high audio frequencies. The influence of the peripheral circuit around an op-amp as well as some history are discussed e. g. in  this thread. Two major points there: (1) Although early op-amps and also transistors had some inherently negative properties which resulted in strong limitations for a good design, these problems have been overcome with today's technology of production and application. (2) As also frequently stated, it's not the component itself that matters, it's rather the circuit designed around it.

That said, I'm going to post some observations / assumptions with a call for comment:
- When the first op-amp IC's became commercially available in the 70's, you would more or less often get bad sounding designs because some effects of NFB in audio circuitry (TIM= Transient Intermodulation Distortion, aka SID= Slewing Induced Distortion) weren't widely known and first had to be addressed. Years and decades later, these effects have been overcome, but somehow the bad reputation of the IC has persisted and become a dogma.
- Modern solid state high gain amp's allow for high level NFB, which, if applied properly, drastically reduce nonlinear distortion components. On the other hand, e. g. vintage tube amp's have less gain but also less NFB applied, which results in less suppression of distortion, where the remaining distortion components are of low order. Now my assumption would be that the difference between high and low NFB amp circuits is not characterized by some "mysterical" high order(?) distortion added by high NFB, but rather the presence of low order distortion in low NFB amp's (or, hence, the absence thereof in high NFB amp's).  
- There are good and bad IC audio circuits as well as there are good and bad tube or solid state discrete circuits. In other words, being too categorical about circuit topology leads away from reality.

Lastly - I've checked up on the AES papers of 50 years plus some textbooks regarding the issue, but couldn't find too many publications more recent than early 80's... anyone know of newer sources worth reading?

Cheers,

[Jim Williams]

Negative feedback is the basis of all operational amplifier design. Without it, the open loop gain would by massive. Try running an opamp at 40 db gain with less feedback, then attenuate the input by 40 db. Sounds like crap, doesn't it?

The negative feedback is what lowers distortion. It's like pounding the small dents in your car fender into even smaller dents. If you want better resolution of low level details, use an opamp with large open loop gain in the audio band. Most "audio" opamps don't meet this criteria with their 60 db open loop gain at 10k hz. Wide band opamps have open loop gains of 90 db at 10k hz, 30 db more distortion corrective negative feedback than audio devices. High slew rates are another benefit as slew and IMD distortion is very low.

The resulting audibility of these low level details is proof that many opamps are filters, but it has nothing to do with negative feedback.

So, not all IC's kill music, just the ones designed for audio.

[vernier]

Oh man, here we go again.

[Terry Demol]

Jim Williams wrote on Thu, 11 August 2005 14:33

Negative feedback is the basis of all operational amplifier design. Without it, the open loop gain would by massive. Try running an opamp at 40 db gain with less feedback, then attenuate the input by 40 db. Sounds like crap, doesn't it? The negative feedback is what lowers distortion. It's like pounding the small dents in your car fender into even smaller dents. If you want better resolution of low level details, use an opamp with large open loop gain in the audio band. Most "audio" opamps don't meet this criteria with their 60 db open loop gain at 10k hz. Wide band opamps have open loop gains of 90 db at 10k hz, 30 db more distortion corrective negative feedback than audio devices. High slew rates are another benefit as slew and IMD distortion is very low. The resulting audibility of these low level details is proof that many opamps are filters, but it has nothing to do with negative feedback. So, not all IC's kill music, just the ones designed for audio.

Question:

Do these high frequency/speed chip upgrades subjectively sound
like they have more HF or less? Does the soundstage come
forward or go backward?

Cheers,

Terry
 

[volki]

vernier wrote on Thu, 11 August 2005 15:52

Oh man, here we go again.

well, not quite - I actually tried to address this from a point where most other threads stop =)  which i had at least tried to make clear... and thought I'd also get some appropriate comments. yours wasn't too informative, was it?

[dcollins]

Jim Williams wrote on Thu, 11 August 2005 06:33

So, not all IC's kill music, just the ones designed for audio.

I was wondering if you had any thoughts on "Rumours" or "The Wall" that were mixed on consoles full of uA709's, which the last time I checked, were IC op amps.

How did the music survive, I axe you?

DC

[Tim Gilles]

*Props up left side of water cooler with a totally untouched copy of Ken Pohlmans "Advanced Concepts in Digital Audio*

*Cracks open a bottle of Lagavulin 18yr old*

*Lights Partagas Double Corona*

*Crosses feet on computer workstation desk*

*Places brief interstellar phonecall on class A walkie-talkie lifted from the belly of a sunken North Korean diesel sub, to invisible colony of mutant crickets running offshore drilling rigs on Phobos 9*

*Puts 100% discrete cattle prod/flare pistol in mouth*

*Thinks happy thoughts*

Again.

Tim "Rumblefish" Gilles

[PookyNMR]

Tim Gilles wrote on Fri, 12 August 2005 21:53

*Cracks open a bottle of Lagavulan 18yr old* *Lights Partagas Double Corona*

Now there's some audio tools worth discussing!  

[volki]

OK, now in very brief words:

There exist tons of in-depth EE info denoting great linearity of modern IC circuits. Also, everyone knows that discrete (especially  tube) gear has more nonlinear distortion, but of low order. Which can be favourable depending on the application.

What I'd like to see is a scientific explanation from those people who claim that IC circuits are never good for any application. Basically, all statements I've  heard out of that "camp" are either just opinions or, well, "pseudo" scientific arguments expressed in a somehow blurry way, so that they can't be backed up by hard facts.

Anyway, if I should keep getting posts such as by Tim Gilles (yawn) I'm not gonna waste my time here any longer and will go on assuming that the percieved differences between discrete and modern IC actually is the absence of low order distortion in the latter topology. Which would perfectly make sense to me, actually. E. g. the "fine information" - which discrete circuits are said to process so much better - would be the original information enhanced by low order distortion products, which makes the signal more "robust" in the way that the generated harmonics and IM products accentuate certain sonic properties.

[vernier]

Soundwise, I've had issues with gear containg ICs, but Drawmer gates sound ok (have no idea whats inside though).

[maxdimario]

Lagavulin is *16* years old.............Hic!

[Tim Gilles]

maxdimario wrote on Mon, 15 August 2005 10:01

Lagavulin is *16* years old.............Hic!

Not all of it...

Comes in a few flavors... And the 18yr old Special Distillers Reserve is da killa!!!

Drink enough of it daily and you might stop hearing those friggin' IC's.


I've been mixing on a 9098i for 6 years.... Damn thing is CHOCK FULL of 'em..

Hell.... I can't even hear 'em anymore.


Tim "Rumblefish" Gilles

[Jim Williams]

Terry Demol wrote on Thu, 11 August 2005 18:10

Jim Williams wrote on Thu, 11 August 2005 14:33 Negative feedback is the basis of all operational amplifier design. Without it, the open loop gain would by massive. Try running an opamp at 40 db gain with less feedback, then attenuate the input by 40 db. Sounds like crap, doesn't it? The negative feedback is what lowers distortion. It's like pounding the small dents in your car fender into even smaller dents. If you want better resolution of low level details, use an opamp with large open loop gain in the audio band. Most "audio" opamps don't meet this criteria with their 60 db open loop gain at 10k hz. Wide band opamps have open loop gains of 90 db at 10k hz, 30 db more distortion corrective negative feedback than audio devices. High slew rates are another benefit as slew and IMD distortion is very low. The resulting audibility of these low level details is proof that many opamps are filters, but it has nothing to do with negative feedback. So, not all IC's kill music, just the ones designed for audio. Question: Do these high frequency/speed chip upgrades subjectively sound like they have more HF or less? Does the soundstage come forward or go backward? Cheers, Terry   Less high frequency hash, less strident top end. But more low level details at 15 to 20k. It's a different type of top end, more natural. It's like when you walk by a jazz club and hear the details and varible tones of a drummer's ride cymbal. Ever hear that on a recording? Soundstage is solid and tight. I find when mics, pre's, recorders, and monitoring are all working together I can pop on some headphones and hear where everyone is with just a pair of HQ mics in the room. I can point where they are and guess how many feet back they are. Of course, other than those fortunate to have heard this type of quality, most of you will have no idea what I'm talking about here. It's like trying to describe colors to a blind man.

[Jim Williams]

vernier wrote on Sat, 13 August 2005 23:55

Soundwise, I've had issues with gear containg ICs, but Drawmer gates sound ok (have no idea whats inside though).

The deadly TI TLO72 opamps, you know, the ones that drove up the prices for discrete English consoles.

[Jim Williams]

dcollins wrote on Fri, 12 August 2005 17:12

Jim Williams wrote on Thu, 11 August 2005 06:33 So, not all IC's kill music, just the ones designed for audio. I was wondering if you had any thoughts on "Rumours" or "The Wall" that were mixed on consoles full of uA709's, which the last time I checked, were IC op amps. How did the music survive, I axe you? DC

Barely, I think. The Rumours album is very dark without any cymbal definition. After all, with 9 months of stupid overdubs, they wore the master 2" out. The album was mixed from the 2" safeties, so it's already a generation removed from the listener.

The Wall is very harsh from the early SSL 4k. A better example is the "Momentary Lapse of Reason" album originaly mixed on a SSL 4k with those dbx vca's. Apparently the sound was so harsh, the Floyd remixed the whole thing on a later model SSL. I have both versions. I can't even listen to the original anymore.

Great music will survive any medium. Robert Johnson is the perfect example. Unfortunatly, our technology tends to get in the way sometimes.

[vernier]

TI TLO72s in the signal path?

[dcollins]

Jim Williams wrote on Tue, 16 August 2005 06:19

The Wall is very harsh from the early SSL 4k.

At Producers Workshop?  You must be thinking of something else!

DC

[Nicolas]

With threads like this, "Mixing in the Box" gets set into a whole new perspective...no ICs anywhere in the mixing signal path

Volker, do you have a preamp or line mixer design with non-audio ICs to test for comparison?

Just curious to hear that myself.

Best wishes

Nicolas

[volki]

Jim, interesting details.

Nicholas, I have all kinds of different gear here... modern IC, discrete SS, tube. Some examples:

My Neumann/Gefell M7 capsule, combinable with different head amp's ("impedance converters"): With M582 tube units or with MV692 SS units, which have a 2-stage amp: FET followed by BJT, with "global" NFB back to the FET. The latter sound more grainy in the high mids. IMO due to the fact that the limited amount of NFB (dictated by the max. gain of the 2 transistors) isn't enough to suppress overall distortion. actually, 4th order and up aren't negligible here (did some measurements once).

Filtek MK5 and Neumann W495b, both IC-based EQ's from the late 70's. The W495b sounds incredible at high and mid band, one of the best IC based EQ's I've heard. The Filtek is terribly grainy up there, but cool for non-critical sources and for everything LMF/LF.

Eckmiller W86a and Teldec MPE10, both passive EQ's. The Eckmillers rule on LF and HF, where the Teldec's (although supposedly custom made by Neumann?) don't really sound usable at most of the settings.

At last some pre's:
+ Siemens V72 - makes the signal beefy & robust to work with. I attribute that to the low order nonlinear distortion that the tube circuit introduces. The xformers have a remarkable share here @LF (and, with high levels, even @MF)
+ Siemens V276 - late 60's SS, not as much character as the V72, but still very usable
+ TAB V676a - mid 70's SS, more complicated circuit but definitley discrete. sounds "hifi" in a way: a little very accentuated top end and over-present lows. (a specialty amp IMO, not good for many app's. i really can't see why this thing keeps fetching high prices)
+ Mackie 8bus - ok, this isn't "top of the line", but something i used to work with... sounds dull & lifeless
+ AMEK 9098 - sounds veery present in contrast, to the point of brittle almost (YMMV). Not my favourite, either
+ SPL Gold Mike is somewhere in between. Oh yeah, it's combined IC / tube btw

Overall i'd say that, as far as pre's are concerned, tube types are more "forgiving" to critical signals. IMO this doesn't hold for other types of gear, though.

[Jim Williams]

vernier wrote on Tue, 16 August 2005 15:58

TI TLO72s in the signal path?

Yep. Toss in some BurrBrown OPA2134's or Linear Tech LT1358's.

Be happy.

[Nicolas]

Volker,

sorry, I think I was being unspecific.
I meant, did you actually take an IC-based preamp and take the audio ICs out to replace them with the aforementioned ICs which are  not designed for audio use?

Or, have a preamp design that uses ICs not intended for audio in place of audio-ICs?

All the best,

Nicolas

[Ryan Massey]

dcollins wrote on Tue, 16 August 2005 19:28

Jim Williams wrote on Tue, 16 August 2005 06:19 The Wall is very harsh from the early SSL 4k. At Producers Workshop?  You must be thinking of something else! DC

I actually have the Trident TSM that used to reside at Producers Workshop.  Lot's of TLO71's.  It has always sounded great and with a recent recap, it's sounding better than ever.  Discreet is good stuff, but I love this board dearly and everone who comes through the studio seems to dig it too.  To each their own.

[maxdimario]

Quote:

18yr old Special Distillers Reserve is da killa!!!

...Heeeyyy! gotta try that out.


As a small child that knew nothing about audio electronics, I remember when I began to hear records that sounded 'different', more distant and washy. The human element and natural-ness were not as evident as some of the older tunes.

The high-frequencies were different, more of a pastel wash.

I now realize that that emotional reaction I had was due to IC circuits.

(and I remember Abbey Road having a different effect on me when compared to the tube recordings of the Beatles, as well)

There is an EMOTIONAL effect due to the signal path.

Oddly enough at that age, I was satisfied to hear the music on a mono tape recorder, as well as other non hi-fi reproducers, but I could feel the difference anyway.

The most important thing is getting from mic level to line level without losing immediacy and intimacy.

[dcollins]

maxdimario wrote on Thu, 18 August 2005 06:31

There is an EMOTIONAL effect due to the signal path.

Then how do you explain why I like to sing along and pound my palm on the roof "Big Lebowski style" when the right song comes on my car radio?

My all IC car radio.

From the all IC radio station.

Possibly from an all IC satellite 22,500 miles away.

You would think all the creamy musical goodness would be wiped clean off, now wouldn't you?

Just to prove I'm stone-deaf, I've also heard what I believe to be "immediacy and intimacy" from my all IC clock-radio, which sports a 3" speaker..........

DC

[vernier]

No no ..ICs in your radio and the station with their horrible limiters can't keep down the very best all-analog recordings. As example (of perfection) would be the Doors. They still sound way better then almost anything newer (even on the car radio) and I'm not even a fan of that group.

[volki]

Nicolas wrote on Wed, 17 August 2005 14:54

Volker, sorry, I think I was being unspecific.

err, no, actually I guess I didn't read your post closely enough

Quote:

I meant, did you actually take an IC-based preamp and take the audio ICs out to replace them with the aforementioned ICs which are  not designed for audio use? Or, have a preamp design that uses ICs not intended for audio in place of audio-ICs?

well, no to both. But I wasn't the one who postulated that audio IC's were bad for audio (confusing me with someone else?). Actually, I'm not even sure which of the more recent opamp's were designed for audio, and which are general purpose...

[volki]

maxdimario wrote on Thu, 18 August 2005 15:31

The most important thing is getting from mic level to line level without losing immediacy and intimacy.

in other words this would mean that the critical part is the high impedance circuits. hmm...

[maxdimario]

Yep.

that, and being careful not to squeeze too much current-capability out of the output circuit.

[ammitsboel]

dcollins wrote on Fri, 19 August 2005 03:10

Just to prove I'm stone-deaf, I've also heard what I believe to be "immediacy and intimacy" from my all IC clock-radio, which sports a 3" speaker..........

Maybe you are stone-deaf?

[Tim Gilles]

ammitsboel wrote on Fri, 19 August 2005 06:59

dcollins wrote on Fri, 19 August 2005 03:10 Just to prove I'm stone-deaf, I've also heard what I believe to be "immediacy and intimacy" from my all IC clock-radio, which sports a 3" speaker.......... Maybe you are stone-deaf?

Man.... it's rough when ya don't make the cut for Freshman debate.

Hurts even more than not making Band and Glee Club.

Ahh hell.... Console yerself.....

Go buy yourself something....


Something big....





Big....














Speakers!!!!



Yeah!! That's it!


BIG FUCKING SPEAKERS!!!




Tim "Rumblefish" Gilles

[Larrchild]

This Opamp looks promising.


L. Janus

[vernier]

If your clock-radio has decent sized magnets (which some Teac's do) it can sound quite nice ..especially with an awesome CD such as the mighty IICORMN.

[dcollins]

Larrchild wrote on Fri, 19 August 2005 17:03

This Opamp looks promising. L. Janus

Unless you have to drive a load.

Where did the schema come from?

A NIKE missile?

DC

[Tim Gilles]

dcollins wrote on Fri, 19 August 2005 22:36

Larrchild wrote on Fri, 19 August 2005 17:03 This Opamp looks promising. L. Janus Unless you have to drive a load. Where did the schema come from? A NIKE missile? DC

Ya know.... I lay in bed at 10am this morning laughing like a madman because this quote(which I first read a day or two ago....), suddenly popped in my head for no apparent reason. I managed to inadvertently wake my wife, who inquired dryly about the source of my mirth, and realized I would be hard pressed to explain WHAT exactly was so funny about the quip in less than an hours time.

I think it would qualify as a instance of empathic humor.

Tim "Rumblefish" Gilles

[Bob Olhsson]

dcollins wrote on Fri, 19 August 2005 21:36

Unless you have to drive a load.

Don't bring THAT up...

[dcollins]

Tim Gilles wrote on Sun, 21 August 2005 10:16

Ya know.... I lay in bed at 10am this morning laughing like a madman because this quote(which I first read a day or two ago....), suddenly popped in my head for no apparent reason. I managed to inadvertently wake my wife, who inquired dryly about the source of my mirth, and realized I would be hard pressed to explain WHAT exactly was so funny about the quip in less than an hours time. I think it would qualify as a instance of empathic humor.

And to think for once I was being serious!  (mostly)

They used tube opamps in the NIKE missles, and it would have been around the time Bel Losmandy was designing aerospace stuff..

That said, I take laughs wherever I can get 'em, so thank you.

DC

[thedoc]

Losmandy's DOG would laugh.