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Topic: DACs and Noise Injection (Read 8572 times) previous topic - next topic
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Re: DACs and Noise Injection

Reply #25 –
Thanks for both those substantive replies.  So, when Oppo says their more expensive Oppo 105 sound better than the 103 (imputed to a better analog side) that is not true?

Also, I thought that op amps were (claimed to be) less hifi than discrete devices?  Not so?

I see some spendy DACs with tubes sticking out of the top.  I assume that provides a nice visual stimulus to those who love the (euphonically distorted) sound of tubes, and may well alter the sound too, not just the perception.  It's not for me in either case.

BTW, the Power Boss mod was supposed to greatly enhance the SQ of the Cal Audio player - no idea  if that is true, but I am impressed that it sounded so similar to a 20 years newer Oppo.

Re: DACs and Noise Injection

Reply #26 –
Quote
So, when Oppo says their more expensive Oppo 105 sound better than the 103 (imputed to a better analog side) that is not true?
I don't know, but there's no reason for any DAC to have any audible defects/deficiencies so hopefully there's no difference.

Quote
Also, I thought that op amps were (claimed to be) less hifi than discrete devices?  Not so?
False.  It's cheaper & easier to make a good quality preamp (or other audio circuit) with an op-amp.   (Early IC op-amps may not have been up to the task, but modern op-amps can be very-good.)

...Actually, op-amps were originally built with discrete components before they were manufactured as integrated circuits.   But, they were expensive and rare (I've never seen one), and as far as I know they were not used for audio (although they may have been used for audio in certain scientific/laboratory applications).  

Quote
I see some spendy DACs with tubes sticking out of the top.  I assume that provides a nice visual stimulus to those who love the (euphonically distorted) sound of tubes, and may well alter the sound too, not just the perception.
You'd have to take it  case-by-case.  It's possible to make a good amplifier (or other audio circuit) with 50-year old technology, but again it's cheaper & easier with modern electronics.    And of course, it's easy to generate distortion either way (or with software).    It's also possible to design a good tube circuit that's relatively immune to tube variations or it's possible to make a less-stable design that behaves differently with different tubes or as the tube ages.


     

Re: DACs and Noise Injection

Reply #27 –
Quote from: rw11 on
So, when Oppo says their more expensive Oppo 105 sound better than the 103 (imputed to a better analog side) that is not true?
Based on a complete and utter lack of substantiation, I think a fair amount of skepticism should be in order.

Quote from: rw11 on
Also, I thought that op amps were (claimed to be) less hifi than discrete devices?  Not so?
Based on a complete and utter lack of substantiation, I think a fair amount of skepticism should be in order.

Quote from: rw11 on
(euphonically distorted) sound of tubes
...or cacophonicly distorted, or not distorted at all;, not that distortion is the only way to characterize audible differences.

Quote from: rw11 on
BTW, the Power Boss mod was supposed to greatly enhance the SQ of the Cal Audio player - no idea  if that is true, but I am impressed that it sounded so similar to a 20 years newer Oppo.
Based on a complete and utter lack of substantiation, I think a fair amount of skepticism should be in order.

None of this is new material on the forum.

https://hydrogenaud.io/index.php?action=search

Re: DACs and Noise Injection

Reply #28 –
Quote from: rw11 on
I am impressed that it sounded so similar to a 20 years newer Oppo.
BTW, if your impressions weren't derived in accordance with TOS8, they should not be proffered here.

Re: DACs and Noise Injection

Reply #29 –
I get the feeling with some manufacturers is they don't care too much about their designs for some of their product lines.  As easy and cheap as it is to make good designs...  You think my HDTV in the living room for example wouldn't have so much hiss out of it's headphone jack.

Re: DACs and Noise Injection

Reply #30 –
Quote from: rw11 on
So, when Oppo says their more expensive Oppo 105 sound better than the 103 (imputed to a better analog side) that is not true?
Isn't it obvious why they would say that? No matter whether it's true or not? (Hint: Marketing!)

I mean, honestly, think about your question -- wouldn't you agree that it was naïve?

Quote
Also, I thought that op amps were (claimed to be) less hifi than discrete devices?  Not so?
They're claimed to be less "high-end". That's got much more to do with price than with quality, and boils down to the same thing: Marketing.

Even within the category of integrated OpAmps, the same argument goes between high-end OpAmps and lesser OpAmps, again having to do with price.

The vanity of all this becomes apparent when you consider that the vast majority of all audio material that you can buy was produced with equipment that had lots of rather modest OpAmps inside, so that the audio would have passed through dozens in a row before it reaches you. Even 20 years ago, manufacturers of studio equipment were buying those chips for pennies (or cents) apiece. In the large majority of cases it hasn't hampered quality noticeably. So the last two OpAmps in your playback device won't have much chance of an impact, unless someone has screwed up.

Re: DACs and Noise Injection

Reply #31 –
I find it challenging to believe that anyone bothering to ask such questions here could be so naive, especially with the high prevalence of sock puppetry involved with these types of posts.

Even if the only reason would be that I negatively view this freeloading JAQ mentality as lazy, thread closure is looming.

Re: DACs and Noise Injection

Reply #32 –
Quote from: greynol on
I find it challenging to believe believe that anyone bothering to ask such questions here could be so naive, especially with the high prevalence of sock puppetry involved with these types of posts.

Even if the only reason would be that I negatively view this freeloading JAQ mentality as lazy, thread closure is looming.

but you are wrong - I am a scientist and believe in testing theories

Thx to the others for bringing me up to date on Op Amps - I have indeed used ones made of discrete components (to amplify signals from instrumentation)

Re: DACs and Noise Injection

Reply #33 –
Quote from: DVDdoug on
...Actually, op-amps were originally built with discrete components before they were manufactured as integrated circuits.  But, they were expensive and rare (I've never seen one), and as far as I know they were not used for audio (although they may have been used for audio in certain scientific/laboratory applications).
It is far more difficult and costly to build a discrete circuit which may still not perform as well as a standard high performance opamp.  Crucial to any performance design is for transistor pairs to be perfectly matched, which is where an integrated circuit has it in spades.

Re: DACs and Noise Injection

Reply #34 –
Quote from: DVDdoug on

...Actually, op-amps were originally built with discrete components before they were manufactured as integrated circuits.  But, they were expensive and rare (I've never seen one), and as far as I know they were not used for audio (although they may have been used for audio in certain scientific/laboratory applications). 

True and there are a number that are still on the market, for example the Jensen 990, for example: WHITE PAPER ON THE CLASSIC jENSEN 990 DISCRETE OP AMP

Also see: http://www.hairballaudio.com/blog/resources/diy-resources/diy-je-990-discrete-operational-amplifier

Discrete op amps go all the way back to the days of tubes:  How op amps were first used in electronics  Check the last page for a great old photo.

Audiophiles being as resourceful and pervasive as they were it didn't take us too long to figure out how to use the op amps in our analog computers for audio back in the 60's. They made the transition from electrical engineering theory to working gear remarkably direct. This took on a life of its own, and here we are.

This is audio so there has been an ongoing controversy over chip op amps and discrete op amps for as long as there were chip amps. The first chip amps such as the 741 were noisy and could be easily coaxed into generating a lot of distortion at high frequencies.  The parts matching and tracking issue raised by Greynol is real and adversely affects some of the parameters of the operation of discrete audio op amps, especially those used at low levels and high gains.

By the time there were 5534 and 5532 chip amps (late 70s early 80s), chip op amps were often quieter and cleaner than a lot of discrete circuitry that was used for the same purpose. The 5532 is still made and designed into new high performance gear, some 30+ years after it was initially released.
 

Re: DACs and Noise Injection

Reply #35 –
Quote from: rw11 on
Thx to the others for bringing me up to date on Op Amps - I have indeed used ones made of discrete components (to amplify signals from instrumentation)
That's certainly possible, although you'd more often combine integrated OpAmps with a few discrete transistors. This method is still widely used for microphone preamps, for example, since it permits using a cheap OpAmp and still achieve very low noise as afforded by the transistors.

But even here, it becomes more and more common to use integrated chips, because it is so much easier to design with them.

A case where discrete designs still are widespread are audio power amplifiers (which in most cases are OpAmps architecturally), because discrete designs are more flexible regarding power, cooling and voltage requirements. But we are in the middle of a transition towards Class-D amplifiers, which are usually integrated.

Quote from: greynol on
Crucial to any performance design is for transistor pairs to be perfectly matched, which is where an integrated circuit has it in spades.
While it is true that transistor matching is much easier on a chip than when using discrete transistors, this is not quite as important in audio as one may think. It merely means that in a discrete design, you have to take care of stabilizing operating points in the face of device tolerances and temperature differences. If that's done properly, the results can rival those of integrated chips. Whether discrete or integrated, you have to do your homework, and since the conditions are different, the designs will differ.

Moreover, you can get matched transistor pairs in small packages, which keep the operating conditions very nearly the same for both transistors in the package. This can give you a bit of what you would have in an integrated chip.

This doesn't mean that I advocate discrete designs over integrated chips. On the contrary, the broad range of OpAmps available today leave very little room for improvements that would call for a discrete design, or a partially discrete design. If you are not a specialist, you are more likely going to end up with an inferior design at higher cost.

Quote from: Arnold B. Krueger on
By the time there were 5534 and 5532 chip amps (late 70s early 80s), chip op amps were often quieter and cleaner than a lot of discrete circuitry that was used for the same purpose. The 5532 is still made and designed into new high performance gear, some 30+ years after it was initially released.
Those are the chips that I referred to earlier when I spoke of OpAmps for pennies. For the last >30 years they have been the price/performace leaders for audio applications, along with the other classic, the TL072, which was/is used when the impedances are higher. Both are sonically transparent when used properly, and they are literally everywhere in audio gear. The fact that the same chips can survive against the competition, over such an extended period of time, goes to show how small the improvements are, and how difficult they are to achieve.