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Quality of AD/DA chipsets Virtual Instrument Plugins
Old 14th August 2008
  #1
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OurDarkness's Avatar
 

Quality of AD/DA chipsets

Hi,

to what extent do you believe that the overall quality of a converter is mostly affected by the quality of the electronics and to a lesser degree by the AD/DA chipset itself?

Are there any high-end converters (like Lavry, DAD, Prism,...) that use off the shelf chipsets for conversion?
Old 14th August 2008
  #2
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duvalle's Avatar
 

as far as i understand there are only a few good chipsets to choose from.
so the chip is not as important imho as the analog I/O circuit design:
op-amps, power-supply, caps and wordclock jitter .....

cheers!
Old 14th August 2008
  #3
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peeder's Avatar
 

I understand Lavry Gold is the only converter still made that doesn't use off the shelf chipsets.
Old 14th August 2008
  #4
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Bob Olhsson's Avatar
 

The filters, power supplies and analog stages make the biggest difference.

None of the high end converters use the onboard filters in the converter chip like the cheap stuff does.
Old 14th August 2008
  #5
The chips determine resolution, noise, etc. Consider the analog the wire to connect it to. A 105 db dynamic range ADC chip with premium analog will not reveal like a 122 db converter with generic analog (5532 type opamps). Combine top-o-line converter chips with high end analog and you are there. Problem is, you don't find the top-o-line converter chips in pro audio gear. It's mostly low cost AKM stuff or some crystal and AD stuff.

Jim Williams
Audio Upgrades
Old 14th August 2008
  #6
Gear Addict
 

chipage

Quote:
Originally Posted by Jim Williams View Post
The chips determine resolution, noise, etc. Consider the analog the wire to connect it to. A 105 db dynamic range ADC chip with premium analog will not reveal like a 122 db converter with generic analog (5532 type opamps). Combine top-o-line converter chips with high end analog and you are there. Problem is, you don't find the top-o-line converter chips in pro audio gear. It's mostly low cost AKM stuff or some crystal and AD stuff.

Jim Williams
Audio Upgrades
hello,

i know, i cannot believe that intelligent people are trying to say that you can polish a ____ with "extreme attention to the analog". it takes both, and the chip is obviously at the heart of it. unless the analog is really crappy, then it actually seems to me that one would probably rather have the better chip set for the resolution and noise advantages. at least this is what i have gleaned from comments from people who actually build stuff.

that said, what do you consider to be a better a to d chip than the akm ak5395a?


userofgear
Old 14th August 2008
  #7
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Nishmaster's Avatar
 

Texas Instruments PCM4222
Old 14th August 2008
  #8
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Stefanizzi's Avatar
 

Quote:
Originally Posted by Bob Olhsson View Post
The filters, power supplies and analog stages make the biggest difference.

None of the high end converters use the onboard filters in the converter chip like the cheap stuff does.
Thank you Bob!

Regards
Old 14th August 2008
  #9
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Stefanizzi's Avatar
 

Quote:
Originally Posted by Jim Williams View Post
[...]Problem is, you don't find the top-o-line converter chips in pro audio gear. It's mostly low cost AKM stuff or some crystal and AD stuff.

Jim Williams
Audio Upgrades
1) Ask yourself why and give us an answer, please.

2) What about Lavry or dCS, aren't they pro audio gear?

Best regards
Old 14th August 2008
  #10
Gear Addict
 

chip , chip, chip.

Quote:
Originally Posted by Nishmaster View Post
Texas Instruments PCM4222

hello,

well, is that not mostly an array design, geared toward low power consumption for console use? i was aware of that and did not see anything in the spec sheet that disposes of the akm ak5394a.

not sure what you were getting at.

mr. williams?


userofgear
Old 14th August 2008
  #11
Quote:
Originally Posted by Stefanizzi View Post
1) Ask yourself why and give us an answer, please.

2) What about Lavry or dCS, aren't they pro audio gear?

Best regards
1) Money. Limited market share due to collapse of the pro recording industry. Lack of well funded research into an industry on the ropes. The prevalance of low fi recording techniques. The prevalance of low fi styles of popular music. The low cost availability of medium quality converter chips. The lack of demand for high quality acoustic recordings including the death of classical recording by the majors. Money. Fashion. The acceptance of systems like Pro Tools.

2) Yes those are fine units. How many do they sell? How many of you want one or can afford one? How many of you have one? How many of you must use one or how many could get the job done without complaint with a medium quality converter instead?

Jim Williams
Audio Upgrades
Old 14th August 2008
  #12
Gear Nut
 
Stefanizzi's Avatar
 

Quote:
Originally Posted by Jim Williams View Post
1) Money. Limited market share due to collapse of the pro recording industry. Lack of well funded research into an industry on the ropes. The prevalance of low fi recording techniques. The prevalance of low fi styles of popular music. The low cost availability of medium quality converter chips. The lack of demand for high quality acoustic recordings including the death of classical recording by the majors. Money. Fashion. The acceptance of systems like Pro Tools.

2) Yes those are fine units. How many do they sell? How many of you want one or can afford one? How many of you have one? How many of you must use one or how many could get the job done without complaint with a medium quality converter instead?

Jim Williams
Audio Upgrades
Thank you Mr. Williams

Best regards
Old 14th August 2008
  #13
Gear Addict
 

oh my

Quote:
Originally Posted by Jim Williams View Post
1) Money. Limited market share due to collapse of the pro recording industry. Lack of well funded research into an industry on the ropes. The prevalance of low fi recording techniques. The prevalance of low fi styles of popular music. The low cost availability of medium quality converter chips. The lack of demand for high quality acoustic recordings including the death of classical recording by the majors. Money. Fashion. The acceptance of systems like Pro Tools.

2) Yes those are fine units. How many do they sell? How many of you want one or can afford one? How many of you have one? How many of you must use one or how many could get the job done without complaint with a medium quality converter instead?

Jim Williams
Audio Upgrades

hello,

right again there, you forgot dlelta sigma oversampling throwing absurd amounts of noise and then having to massage everything into oblivion to make it listenable with no idea what else it might be doing. hooray, lets save money.

the dcs and lavry stuff have their issues too, its all a workaround if you ask me.

in any event, is there actually any commercially available chip that it significantly better than the ak5394a? they said they were trying to work up something to top it.

userofgear
Old 14th August 2008
  #14
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OurDarkness's Avatar
 

Quote:
Originally Posted by peeder View Post
I understand Lavry Gold is the only converter still made that doesn't use off the shelf chipsets.
So, except for Lavry all other manufacturers use off the shelf chipsets?
Old 14th August 2008
  #15
It's kind of hard to imagine that, decades after D/A/D became a broad commercial product, that it's still rocket science. There have to have been a lot of very bright people spending a lot of time on it since then.
Old 14th August 2008
  #16
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u b k's Avatar
 

Quote:
Originally Posted by Dean Roddey View Post
There have to have been a lot of very bright people spending a lot of time on it since then.

doubtless; the question is what are the bright people's priorities? it's a rare breed of person who has both the intellect for optimizing the myriad issues inherent in a basic converter design, as well as the golden ears for tone (either preservation or enhancement) that result in a truly stellar conversion.

we have what, 5 billion people on earth? and how many of them are designing euphonic a/d/a? 20? 40?

i think top-tier conversion is both rocket science *and* esoteric art, hence the rarefied air up there.


gregoire
del
ubk
.
Old 14th August 2008
  #17
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lazzaro's Avatar
 

Quote:
Originally Posted by Dean Roddey View Post
It's kind of hard to imagine that, decades after D/A/D became a broad commercial product, that it's still rocket science. There have to have been a lot of very bright people spending a lot of time on it since then.
The economics don't work ... it's not a lack of ideas ... it's that when you want
to turn the ideas into a going concern, you pencil it out and you realize you'd
never make back the non-recoverable engineering costs of doing a custom
mixed-signal chip to sell to boutique audio converter companies.

And so whatever innovation happens needs to happen at the board level.

On the bright side, for the digital part of a mixed-signal chip, FPGAs provide
a way to do economical design for boutique markets. There's an untapped
market for analog building-block parts designed to mate to FPGAs to do
customized converters for small-volume products. These building-block chips
could be designed on a low-noise analog foundry service like the one THAT provides.
So, they'd have the same sort of workable economics that the THAT VCA chips do.
Old 14th August 2008
  #18
Gear Addict
 

shelflife

Quote:
Originally Posted by OurDarkness View Post
So, except for Lavry all other manufacturers use off the shelf chipsets?

hello,

i do not think that is true. and i think the lavry gold uses chip technology to some extent, but modified. dan lavry limits his converters to 96khz, which he apparently feels works best, at least in his design philosophy.

from what i have heard, there are some things about chip technology that are an advantage [and not just cost-wise]. so, like someone said earlier, many of the manufacturers use "part of the chip". the companies that make the chips design them to allow manufacturers to access them them at different points, or to access different parts of them while bypassing other parts.

some companies are basically just using the manufacturers' evaluation boards with a power supply, and other companies are doing different mods to make them work with their philosophy or product needs and so forth. if the chip is involved, it seems silly to me for people to act like it has no bearing on the sound, particularly where the chip manufacturers are the one's deciding what portions can be accessed in what ways and so forth. what the chip manufacturers will allow third parties to do governs what modifications are even possible.

remember the manufacturers tend to make the technology and chips for use by lots of different industries. video, medical, and so forth, a lot of them may use the same parts. pro audio alone does not support the manufacturers by any means. they make them for a variety of uses.

dcs had their own whole chip design thing with their "ring dac" concept. you can still find dcs converters pretty easily if you want.

daniel weiss has a very good design using the akm chip. i guess he probably has it tweaked to its limits, or better, with his own dsp thrown in there too. real well thought out, with very precise, ganged input sensitivity, good metering and so forth. he does not use two chips for each channel as is often misstated, but he does something like taking two outputs from each chip and combining them in such a way as to lower the noise floor [don't quote me on the details].

there is another technique called "gain-ranging" that tries to use different chips for different parts of the audio band or something like that. all kinds of stuff they try. and some of it works, and some of it not so much.

the one everyone seems to regard as having been the only real "spare no expense" product was the pacific microsonics [model 2, i think]. they do not make them anymore. i think microsoft bought the company and shelved it. i guess if someone wanted to just go all out and not worry about the cost, they could probably do better now anyway.

anyhow, you can also get info about this kind of stuff, and your questions, at bruno putzeys' forum <http://recforums.prosoundweb.com/index.php/f/45/0/>, if you want to jump in. he apparently makes a very good dsd box and he seems very knowledgable.

take care,


userofgear
Old 14th August 2008
  #19
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ben_allison's Avatar
Sorry to semi-hijack;

Mr Williams, over the years on GS that you've mentioned that a world-class converter could be built for a few hundred bucks in parts.

Are there schematics around for converters that would rival Lavry/Prism/Mytek, etc? What kind of time and money would be involved in building a complete 2 channel AD/DA? I'm great with a soldering iron and have DIY'd a few projects and feel up to the task.

Thanks!
Old 14th August 2008
  #20
Quote:
doubtless; the question is what are the bright people's priorities? it's a rare breed of person who has both the intellect for optimizing the myriad issues inherent in a basic converter design, as well as the golden ears for tone (either preservation or enhancement) that result in a truly stellar conversion.
I'm not sure that truely stellar conversion should require any any golden ears or have any tone. If it creates the most accurate representation of the signal possible ,then if you put great tone it into, you'll get great tone out of it, it would seem to me. To me, converters should be like cables. They should be as unobtrusive as possible. Though I'd imagine that those that purposefully sweeten the signal probably seel better for the obvious reasons.

BTW, it doesn't have to be one person, so it's not necessary that you have one person have both those gifts.
Old 14th August 2008
  #21
Gear Maniac
 

Question

How much time does it take for a high end converter to come out?

From what I know the lavry gold already has some years... I know gear is not like computers\laptops but i'll be happy to buy something new

I hope that when USB3 comes they start making new d/a converters!
Old 14th August 2008
  #22
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peeder's Avatar
 

Quote:
Originally Posted by ben_allison View Post
Sorry to semi-hijack;

Mr Williams, over the years on GS that you've mentioned that a world-class converter could be built for a few hundred bucks in parts.

Are there schematics around for converters that would rival Lavry/Prism/Mytek, etc? What kind of time and money would be involved in building a complete 2 channel AD/DA? I'm great with a soldering iron and have DIY'd a few projects and feel up to the task.

Thanks!
I think the burning question actually is,

Why isn't Jim Williams just going ahead and making converters (and everything else) himself and selling them?

All I've seen from him is a mic pre and a guitar amp that someone contracted him to build. Everything else has been about trying to make people feel awful about the "cheap opamps and capacitors" in the work of other designers.
Old 14th August 2008
  #23
Gear Addict
 

and-a-way-we-go

Quote:
Originally Posted by peeder View Post
I think the burning question actually is,

Why isn't Jim Williams just going ahead and making converters (and everything else) himself and selling them?

All I've seen from him is a mic pre and a guitar amp that someone contracted him to build. Everything else has been about trying to make people feel awful about the "cheap opamps and capacitors" in the work of other designers.

hello,

ah, the cosmonaut returns.


userofgear
Old 14th August 2008
  #24
Gear Addict
 

new stuff, yay

Quote:
Originally Posted by 212121 View Post
How much time does it take for a high end converter to come out?

From what I know the lavry gold already has some years... I know gear is not like computers\laptops but i'll be happy to buy something new

I hope that when USB3 comes they start making new d/a converters!
hello,

i almost hate to say this, but you might be waiting to see whatever digidesign does next. i am aware that this may cause numerous readers to throw up, but they may just go for it.


userofgear
Old 15th August 2008
  #25
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rkwyent's Avatar
 

Mr Williams or whom ever else

What I would like to know is:

If many of these newer converter chips (AKM branded the ones i know of) only require maybe a capacitor and one resistor as the output filter, Why is it that the manufacturers add all these additional components around them (OpAmps and stuff) instead of just using slightly better quality components with the simpler design.

I think we as human beings can complicate things just because we want to.

I have a buddy that i work with and he always has do do things the hard way bcuz he romanticises the extra steps to do something that can be extremly simple . I just don't get people sometimes. i guess its another way of feeding the ego.
Old 15th August 2008
  #26
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Quote:
Originally Posted by rkwyent View Post
What I would like to know is:
Well, I know some stuff is for level meter led's, clock-rate selection, power supply... there's probably extra chips that will output different kinds of digital signal (AES/EBU, SPIDF, etc)...
Old 15th August 2008
  #27
Gear Addict
 

good question

Quote:
Originally Posted by rkwyent View Post
What I would like to know is:

If many of these newer converter chips (AKM branded the ones i know of) only require maybe a capacitor and one resistor as the output filter, Why is it that the manufacturers add all these additional components around them (OpAmps and stuff) instead of just using slightly better quality components with the simpler design.

I think we as human beings can complicate things just because we want to.

I have a buddy that i work with and he always has do do things the hard way bcuz he romanticises the extra steps to do something that can be extremly simple . I just don't get people sometimes. i guess its another way of feeding the ego.

hello,

you make a sensible question. i think the chip manufacturers publish their recommendations for implementaion, but a lot of people think they have a better idea. some of them are probably trying to fix something that is not broken. maybe some of them do have a better idea. probably.

i think there are issues of getting the chips to function properly as part of a bigger design project, so that probably necessitates some modification, in some cases. like all these various interfaces people make that are multi-channel. i guess they have to do some tweaking to get the chips all cozy as an array, and clocked properly. probably different if you are trying to get 8 or 16 to groove together than just one or two.



userofgear
Old 15th August 2008
  #28
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rkwyent's Avatar
 

Quote:
Originally Posted by ben_allison View Post
Well, I know some stuff is for level meter led's, clock-rate selection, power supply... there's probably extra chips that will output different kinds of digital signal (AES/EBU, SPIDF, etc)...
Ok. There should be no skimping on the power supply.

Clock rate selectors are usually a simple switch or in most cases a differental voltage to trigger the switch on the chip.

Level meters can be a parallel circuit that doesn't sit in the analog path of the outputs.

digital signal outputs are just that and are usually done adequately.

It is my understanding that the akm 4395/4396 converter chips put out a balanced +4 signal and only needs somethng like 1 resistor and a few capacitors as an output filter for the analog output stage.

So why add so much more to the analog output stage????
Old 15th August 2008
  #29
A/D front ends are mostly similar, a sample and hold circuit to time input signals. DAC's are what you are refering to. Low cost DAC's use on-board opamps and filters to save costs. These are voltage output designs. The better DAC's have current outputs requiring the designer to impliment a current to voltage stage along with a 2 pole analog low pass filter. The BB PCM1704 is a good example of current output DAC designs.

Jim Williams
Audio Upgrades
Old 15th August 2008
  #30
Gear Addict
 
rkwyent's Avatar
 

Quote:
Originally Posted by Jim Williams View Post
A/D front ends are mostly similar, a sample and hold circuit to time input signals. DAC's are what you are refering to. Low cost DAC's use on-board opamps and filters to save costs. These are voltage output designs. The better DAC's have current outputs requiring the designer to impliment a current to voltage stage along with a 2 pole analog low pass filter. The BB PCM1704 is a good example of current output DAC designs.

Jim Williams
Audio Upgrades
Thanks for clearing this up Jim. Are the Crystal (Cirrus) converter chips also voltage output or are they current output?

Also, I notice that some of the better DAC units like Benchmark and Lvry DA10 use AD (Analog Devices [i think]) brand converter chips.

Can someone elaborate?
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