Op amps vs discretes
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- čas přidán 27. 07. 2024
- We hear op amps getting a bad rap in high-performance audio, yet they are completely misunderstood. Learn what an op amp is and the difference between IC chips and discrete components.
- Věda a technologie
Good to see PS Audio breaking into the industrial microwave game.
@Lloyd Stout That comment looks like it took a lot of work.
Now that's funny! Although i would give anything to have one of those amps. Just out of my price range.
Is the trivection oven on its way?
We should all take a second to thank the designers and manufacturers of the NE5532 opamp for giving the world an affordable way to amplify voltage signals in the audio band with next to zero distortion.
i was an engineering technician for Analog Devices when they were in Cambridge, MA (1970). The high end op amps were in a 1-1/2 sq epoxy package that had pins coming out of it that would plug into a socket. The opamp itself was built of di epoxied into a potting shellscrete transistors and FETs with the supporting resistors and diodes on a printed circuit card and that assembly was put into a potting shell with black epoxy. Once that epoxy cured the thing was a monolithic brick.
My job was to build prototypes that we could tweak for optimum performance. Some TO-5 ic's like 709's were just starting to be used ubt these were lower end op amps. if you needed real performance you got the discreet op amp..
I have a few of those with gold pins on them.
Whats the best current op amp for a dac in your opinion? Weiss OP2?
I.C Op amps have come a LONG way, allowing for the design of high end audio devices in a much easier manner. However, some of the BEST recorded material I've EVER heard was all recorded using devices that had audio circuitry that exclusively used discrete op amp circuitry. API consoles have nearly always used discrete op amp circuitry... the old Stephens multitracks used class A discrete circuitry... something you could EASILY hear. A gifted designer can often make you believe that you are listening to a circuit that is discrete, when many times it may perhaps not be so. I.C. op amps cost less, but perform nearly as well as most discrete op amps. Great question, Paul... and great answer as well.
Whats important is discrete front end on a chip based mic preamp. Chip based mic preamps can sound very good and have vintage character especially If TLO 072 /074 is used in the circuit. There is alot of difference between the old chips that have more Harmonic distortion than the never ones that is superclean and silent. API, Trident and Focusrite also use a Audio Transformer Balanced input to there chip based Mic Preamps. Never Mic preamps from Neve also use transformer balanced front end and chip based design. The first chip based design from Neve was the Focusrite Forte console whit the ISA 110 mic preamp module. All new mic preamps designs from Neve after the 1985 Focusrite forte console has been transformer front end and chip based. The new Rupert Neve Design shelford series also use transformer balanced Input with a chip based Mic preamp module.
Of course Neve still sells the Classic all discrete Class A 1073 1081 modules but all newer design series are chip based designs. If you want Discrete Mic Preamps there is alot of Neve 1073 clones like Golden age Pre 73 Warm Audio WA-73.
@@MZ-tm1tw... The reason that manufacturers use integrated circuit op amps is twofold… 1) ease of design and 2) to reduce the cost of manufacturing. If a current console manufacturer used discrete transistors instead of op amps, the cost of the final product would price them out of the market.
The reason that transformers are used in console mic preamps is for signal coloration that is part of the design as with high input signals, the transformer core saturates, providing the signature sound that the manufacturer had designed for.
IC op amps also became more popular in console designs because they allowed for transformerless output circuits, again reducing the cost of manufacture and allowing a product price point that addresses the lower costs that the market desires.
Actually, the first chip-based designs from Neve, the company, were the 8100 series consoles… the 8108 and the 8128, but neither of them were really accepted overall, more than likely due to the FET switching routing matrix, which was quite problematic. However, when Rupert Neve started Focusrite, he employed a superior op amp than did the design engineers at Siemens, who purchased his company, and the right to use the Neve name, from him. By using the 5534, Rupert was able to use a far superior audio op amp for that time. (However, it was the use of the Lars Lundahl input transformer, coupled with the 5534, that gave the preamp its signature sound.) The single version 5534 has a couple of pins that make available certain parts of the op amp circuit that can be used to change the bias of the op amp, and thus give the design engineer a greater variety of sonic qualities.
The API 2520 discrete op amp has a specific large die transistor as its output pair, which is capable of driving a transformer without any assistance… something that an IC op amp cannot do on its own without bogging down and blowing up. Paul Wolff, who purchased API back from Datatronix in the 70s, in moving on the form Tonelux, created an op amp with a separate output pair so that he could save costs, only using large die output transistors when necessary to drive an output transformer and designing the discrete op amp for a particular musical quality. Those who use Tonelux equipment love the sonic qualities that Paul designed into the overall circuit topology.
While IC op amps are great, overall, and manufacturers like Analog Devices make some cutting edge ICs, for the most part they still do not perform at the level of a well-designed discrete circuit as transistor dies can be chosen for the particular sonic properties that they, along with wise choices in resistor and capacitor type, will impart to the final product.
However, other aspects of equipment design can render a well-designed circuit useless. Without employing separate power and ground plane layers in the circuit board design and layout, a great circuit on paper can end up being crap.
In the 70s there was a company out of Texas, Southwest Technical Products, that manufactured amplifier kits, both preamp and power amps. The designs were based on a complimentary differential input, like the one that Hafler finally ended up using. They were warm, very amazing, and some of the best power amps I ever heard, especially considering that they were only $60 each. These were my introduction to great hi-fi listening… sadly they went away too long ago. (Sorry to have digressed.)
The presence of so many clones of classic, class A mic preamps on the market should be more than enough to convince anyone of their timeless qualities in delivering a pristine signal to whatever recording device is employed. By the way, if you’ve never heard of The Hardy Company, John Hardy uses the 990C discrete op amp (of his own manufacture) in minimum parts count mic preamps (that are fully transformer coupled) and sound amazing.
Additionally, designers like George Massenburg utilize fully discrete, transformerless, balanced in/unbalanced out circuits that rival many others. Avalon Designs base their products on class A, discrete, fully balanced circuitry that is some of the quietest in the industry.
In summary, while IC op amps make for a much easier design, and allow for transformerless outputs (thus reducing the cost of manufacture and end user prices) the traditional discrete transistor circuit allows for greater fidelity along with the coloration that many desire… drums and bass are fatter without adding anything else to the circuit. In audio reproduction for the serious listener, discrete circuitry that is well-designed and implemented will bring the listener some of the greatest satisfaction ever… yet with a much higher price tag. I hope that I didn’t bore you with my reply.
@@jimrogers7425 great share
Actually a very good question, and a good answer. However that question could springboard into a much larger discussion on modern amplifier design, hybrid circuits, FPGAs, etc.
Great one today!
Some people have even made full on amps with a bunch of op-amps in series.
A typical example of discrete OP AMP implementation is any power amplifier. While chip op-amps have gone a long long way into high performance, they are still all limited to low rail voltages, in the +/- 15-18V range, and that does indeed introduce some limitations. As for sound quality, I'm "blessed" with no golden ears, so I can relax and enjoy the music.
I was thinking the same thing. You yank the NFB and it slams to its favorite rail or becomes a power comparator . Most power amps I have seen however use the inverting input for NFB only and not for diff input. As we know it's that odd lone stage in the upper middle just a bit to the left that does all the really interesting stuff.
For the truly curious, may I suggest a paperback book called the “Op Amp Cookbook” you may even decide to purchase a kit where you can wire up some of the sample circuits that are described in this book.
@@jim9930 I am very familiar with journal. The book I suggested is for beginners and this man seemed to be a beginner.
@@jim9930 I can only speak for myself. I am a former engineer who has not practiced for over 40 years.
I have that book someplace... great guide.
Well done!
This argument caters for the people who claim they can tell the difference. The difference is nearly always 'different' but not necessarily better and, at a stroke, belittling those IC designers that go the extra mile to make a great performing device. The precision gain matching, great repeatability and superb thermal compensation of an IC op amp is difficult to beat where everything is on a single piece of silicon. The Octave Records Studer console probably uses many proprietary A101 discrete thick film linear amp modules in key areas of the audio chain, but this was before really good audio op amps were available, so it's understandable why they went down that route.
This was really helpful.
I'm old enough to remember (and having built) Op Amps using tubes and transistors. Oh, God!
Generally, DC-Coupled, very high-gain, low noise, with feedback, so low distortion.
Chip versions are generally absolutely fine (and _very_ cheap) but some _discretion_ may be advised. See what I did there?
Quality explication of quality circuits
great video
Once again this is one of those topics can go around in circles ALL day. If ANYONE does a double blind listening test with an op-amp vs. a discrete transistor headphone amp you will be hard pressed to hear a difference. Ultimately it's the total circuit that "voices" the amp, (or pre-amp) NOT whether or not the circuit uses chip-based op-amps. However most audio op amps have strict output loading and compensation requirements. In addition it's fairly difficult to find perfectly matched (complimentary paired) discrete transistors. Discrete transistor circuits are really required for Power Amps only. Since just about every modern day recording console is overloaded with op-amps, adding a few more into the playback path isn't really going to make a difference.
Nicely explained. Can you enlighten with your view on replacing 5532 with 4562.
BURR-BROWN !
Thanks!
Not every OpAmp have single ended output. On the contrary, most of them have push-pull output in class AB or B.
Time to hit the breadboard! I have a ton of CMOS chips, timers, op amps, 8 bit shift registers and other goodies that I’d like to use to make an analog voltage sequencer for controlling synthesizers.
There is no limit to how many layers you can stack into a synth. But eventually you have to do it with software then write it to hardware and call it um, let me see, uh Oh Hell let's call it DSP.!
Paul's sermon was pretty inspirational today though.
I wanted to make a class D tube amp but I found it's been done and it sucked. I'm not sure I believe it but I'm stubborn that way.
@@InsideOfMyOwnMind eventually WHO has to write software? There’s no reason in today’s day and age why things can’t be all analog if desired
@@graxjpg Then you'll find it interesting that a well known active speaker manufacturer who had a DSP based input section on their speakers have replaced them with ones that use a similar looking ASP chip and it sounded way better.
opamps, the chip kind used in audio for voltage gain, like the NE5532, are excellent at what they do. What you put in is what you get out, period, no arguments about that. The thing is, they just dont 'colour' the audio which can be extremely boring. Marshal has made hundreds of millions of dollars of distortion because it sounds good.
So like DACs, are build with a dedicated chip, a FPA chip or a R2R ladder. All convert D 2 A
So, It looks like the question should be discrete op amps VS chip op amp?
Not necessarily so, with discrete parts you are not restricted to a 'traditional' op-amp design, you can make all sorts of almost, or wannabe 'op-amps' as your final product may require.
Paul have you tried Sparkos lab discreet op amps?
Ermmmm no 😂. That’s why I leave building amplifiers to you guys and I just listen to them.
What type of opamp is used in the signal paths of Octave Records?
Cheeky question...
I bet there will be a number of NE5532 chips somewhere in the loop. :)
@@savvassidiropoulos5952 In my FOSI audio tube P1 Preamp there is two of them on a socket so I can upgrade them if I want to.
The Studer desk with the Neil Young provenance they use is loaded with NE5532 chips.
What's that poster in the background? I always get in trouble for using that word.
Michellin calendar I suspect.
Tryn to make DIY "cable cooker". Can't quite understand the plans. Hmmm..
I see a picture of a cereal box behind Paul.
Great explanation.
What do you call an IC with only 1 transistor on it - a discrete. Designing an op amp on an IC comes with benefits and limitations over a handful of discretes but fundamentality the resulting sound quality is the result of the silicon process or processes used and good design, one is not necessarily better than the other.
Isn't the real reason PS Audio use discrete Op-Amps is so it looks better under the hood? Hard to justify a high price using IC Op-Amps.
99% true :)
Technically correct, but...
you could never fit a turkey in one of those PS audio microwaves
I think you made it sound quite complicated Paul, all it is a circuit diagram of the chip, if in solid-state form with transistors resistors and diodes is the discrete op amp,
feedback the subwoofer on the unused channel flip it out-of-phase should I use a 0,1 capacitor or just straight in the input?
No he didn’t, you did. Lol.
@@ramsaybolton9099 ok people don't understand it maybe they do find it complicated I thought I made it sound more easier to understand good to have you feedback!
Paul comon you flunked this one !! you should have used a white board because you lost me with those hand signs
A whiteboard would have helped :)
Kenny G's brother.
WHY is there never anyone doing any work at this place?
Because I shoot the videos on Saturday when everyone has the weekend off.
@@Paulmcgowanpsaudio Mega Burn!
Why is it called an operational amplifier? Does this mean there’s a non-operational amplifier?
Because it use to be used in analog computers to do basic operations like adding or multiplication. In fact you can even do derivatives and integrals. Hence operational amplifier.
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Does anybody know where this guy received his electrical engineering degree?
hehehe.... as though one were necessary.
You can read book about electrical engineering. And the truth you can't complete all chapters even in your PH.D.
@Douglas Blake that one quote from "Good Will Hunting"" lol. I give more respect to someone who is self taught and has the same knowledge than someone who was institutionally spoon-fed, not to say that it isn't hard work. You can skip the degrees and go straight to the top paying jobs by learning the cutting edge of technology all on your own... in the 70's it was IC/amplifier design. Want proof? Look up FPGA design, some of the biggest houses pay top dollar not for a piece of paper, but for what you can get an FPGA to do. Dev boards and manuals and a whole lotta motivation is all it takes.
@Douglas Blake plenty of engineers dont know what they get wrong. Im sure you know a few.
che fai nella vita?
With an IC you make your circuit according to it's spec, with discrete you do whatever you want.
Everything else equal you'd be hard pressed to hear the difference.
Op amps????? Omg!! Wtf??
Those dopey units with a dozen AC duplexs is such a violation of so many basic NEC and UL listing safety standards...how do you sell such poorly untested unsafe products?