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Author Topic: Apogee's design?  (Read 5341 times)

Werewolf10

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Apogee's design?
« on: July 21, 2006, 03:07:15 AM »

Hello peoples

    About a year ago I called AKM semiconductor to ask some tolerance questions about some ADC's.  After about 20mins of broken english and jumping from person to person, I finally got around to talking to one of their lead engineers.  He was very very helpfull with my voltage questions regarding one of their chips, but then we went on to talk about some other companies that use their chips.  

To make a long story short, he said that out of all the companies they deal with, Apogee are the only ones that actually "tweak" the D/A converters after they are sent to them.  I said "what do you mean tweak"?  He said that they "actually open them up and make some minor design changes".  

So I am wondering,  Does this mean that when you are listening to a signal through the DAC of an Apogee device, you aren't really hearing whats on the hard drive?  Cause this seems a little suspicious to me.  I was talking to Bob Katz a few years ago and he said that, and I quote, "Apogee converters are colored".  Now im thinking their AD is not , but their DA is..

This seems a little sleezy to me,, kinda like the studio/band scenerio where the singer says "man it sounded great in the studio, but it sucks in every cd player I put it in".  Because if you tweak the DA, just to give you the illusion that the unit is better than what it is,, aren't you kinda throwing off the mixing process??  DAC's seem like an area where you want the "truth to be told"...

Just my paranoid suspicious 2 cents. Razz
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Andy Peters

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Re: Apogee's design?
« Reply #1 on: July 21, 2006, 04:01:30 AM »

Werewolf10 wrote on Fri, 21 July 2006 00:07

To make a long story short, he said that out of all the companies they deal with, Apogee are the only ones that actually "tweak" the D/A converters after they are sent to them.  I said "what do you mean tweak"?  He said that they "actually open them up and make some minor design changes".


Does Apogee buy bare dice, then have them trimmed and packaged?

-a
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Jon Hodgson

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Re: Apogee's design?
« Reply #2 on: July 21, 2006, 05:51:37 AM »

This sounds HIGHLY unlikely.

As far as I know, every major ADC and DAC out there is a monolithic circuit, basically a chunk of doped silicon with some metal tracks stuck on top of it.

All of these components being a few micrometres across.

There's nothing to tweak!

Theoretically Apogee could request their own run of chips with slightly different specs, but the problem with this is that Apogee are not going to be a big customer (relative to customers who are shipping millions of soundcards or DVD players), so this would normally be very expensive.

Who were you speaking to? Because it sounds to me like somebody has misunderstood something in this conversation.

However I will agree with you that a DAC, especially one in a mixing situation, should ideally be completely transparant.
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danlavry

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Re: Apogee's design?
« Reply #3 on: July 21, 2006, 02:15:58 PM »

Jon Hodgson wrote on Fri, 21 July 2006 10:51

This sounds HIGHLY unlikely.

As far as I know, every major ADC and DAC out there is a monolithic circuit, basically a chunk of doped silicon with some metal tracks stuck on top of it.

All of these components being a few micrometres across.

There's nothing to tweak!




Hi Jon,

The LavryGold products are NOT a chunk of doped silicon IC. They are made "from scratch", custom resistor networks, a rather unique architecture including very involved calibration schemes... Look at the DA924 and you find no commercial DA IC's. There are "tons" of parts but no Dac IC's in the signal path. The Model 3000S optimizer does sample rate conversion without an SRC IC....

Regards
Dan Lavry
http://www.lavryengineering.com
 
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Jon Hodgson

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Re: Apogee's design?
« Reply #4 on: July 21, 2006, 03:49:09 PM »

danlavry wrote on Fri, 21 July 2006 19:15

Jon Hodgson wrote on Fri, 21 July 2006 10:51

This sounds HIGHLY unlikely.

As far as I know, every major ADC and DAC out there is a monolithic circuit, basically a chunk of doped silicon with some metal tracks stuck on top of it.

All of these components being a few micrometres across.

There's nothing to tweak!




Hi Jon,

The LavryGold products are NOT a chunk of doped silicon IC. They are made "from scratch", custom resistor networks, a rather unique architecture including very involved calibration schemes... Look at the DA924 and you find no commercial DA IC's. There are "tons" of parts but no Dac IC's in the signal path. The Model 3000S optimizer does sample rate conversion without an SRC IC....

Regards
Dan Lavry
http://www.lavryengineering.com
 


Hi Dan,

Perhaps I should have been clearer in my definition.

I was referring to DAC ICs, which is what the original poster was referring to. I was not referring to the complete DAC circuit, whether that includes a DAC IC or not.

Thanks for the information on your products though, are the Gold ADC units also made "from scratch"?

regards

Jon
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danlavry

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Re: Apogee's design?
« Reply #5 on: July 21, 2006, 04:23:09 PM »

Jon Hodgson wrote on Fri, 21 July 2006 20:49

danlavry wrote on Fri, 21 July 2006 19:15

Jon Hodgson wrote on Fri, 21 July 2006 10:51

This sounds HIGHLY unlikely.

As far as I know, every major ADC and DAC out there is a monolithic circuit, basically a chunk of doped silicon with some metal tracks stuck on top of it.

All of these components being a few micrometres across.

There's nothing to tweak!




Hi Jon,

The LavryGold products are NOT a chunk of doped silicon IC. They are made "from scratch", custom resistor networks, a rather unique architecture including very involved calibration schemes... Look at the DA924 and you find no commercial DA IC's. There are "tons" of parts but no Dac IC's in the signal path. The Model 3000S optimizer does sample rate conversion without an SRC IC....

Regards
Dan Lavry
http://www.lavryengineering.com
 


Hi Dan,

Perhaps I should have been clearer in my definition.

I was referring to DAC ICs, which is what the original poster was referring to. I was not referring to the complete DAC circuit, whether that includes a DAC IC or not.

Thanks for the information on your products though, are the Gold ADC units also made "from scratch"?

regards

Jon



Hi Jon,

  I meant DAC IC's! There are no audio DAC IC's inside the LavryGold DA924. The product is not designed around an exsiting DAC IC. The DAC itself is made from scratch!

  You are correct to say that MOST DA's are based on parts surrounding a ready made DAC IC, to make a whole product. In the case of the DA924, it is really designed from scratch, thus NO DAC IC.

  Design from scratch is a huge undertaking! I began with sigma delta, but then switched back to a resistor based architecture, which is NOT a standard R-2R, nor is it any other standard architecture, such as found in IC's. These have some "built in problems", so it called on a different circuit aproach, to be free from those problems.

Regards
Dan Lavry
http://www.lavryengineering.com


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davidstewart

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Re: Apogee's design?
« Reply #6 on: August 11, 2006, 03:48:05 PM »

As I understand it there are a number of DAC/ADC chips that allow for certain tweaks (i.e. filtering) to be done outside of what is built onto the chip itself.
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