CAST technology, how much do you know?
Aug 26, 2009 at 10:23 PM Post #16 of 63
Quote:

Originally Posted by anetode /img/forum/go_quote.gif
What is the SATRI circuit responsible for?


It's rather hard to tell exactly because Kingwa is always conflating between SATRI and CAST.

But basically, the SATRI circuit is a transconductance amplifier which takes an input voltage and outputs a proportional current, as opposed to a regular voltage amplifier which takes an input voltage and outputs a proportional voltage.

The SATRI "amplifies" the signal by shoving its output current through a resistor.

If you're familiar with Ohm's Law, you'll know that voltage is equal to current times resistance. So if you have a given current, changing the value of the resistance that current is flowing through will change the voltage across that resistance.

And if you make that resistance variable, then you can use it for volume control.

k
 
Aug 26, 2009 at 10:54 PM Post #17 of 63
Thanks for the explanation, I too was confused by the SATRI/CAST terminology.

It seems that the engineering concepts are pretty straightforward and have an established history of use. Kingwa's use of the acronyms is in line with the usual Chinese KIRF MO (KIRF -- Engadget).
 
Aug 26, 2009 at 11:05 PM Post #18 of 63
Quote:

Originally Posted by anetode /img/forum/go_quote.gif
It seems that the engineering concepts are pretty straightforward and have an established history of use. Kingwa's use of the acronyms is in line with the usual Chinese KIRF MO (KIRF -- Engadget).


Yeah.

He even uses the same damn model number on his own SATRI clone, BPM7110. "BP" of course standing for Bakoon Products.

Talk about shameless.

k
 
Aug 27, 2009 at 12:11 AM Post #20 of 63
Quote:

Originally Posted by haloxt /img/forum/go_quote.gif
Just curious, would everything be kosher if audio-gd just gave credit to bakoon for designing the circuit?


It wouldn't make what they've already done any less sleazy.

Their ethical character has already been revealed.

k
 
Aug 27, 2009 at 1:54 AM Post #21 of 63
Kingwa would have to license the rights to the relevant trademarks. Given that he's already pissed all over their IP, I doubt that Bakoon or Krell would offer him a decent deal.
 
Aug 27, 2009 at 3:42 AM Post #22 of 63
Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif
It's rather hard to tell exactly because Kingwa is always conflating between SATRI and CAST.

But basically, the SATRI circuit is a transconductance amplifier which takes an input voltage and outputs a proportional current, as opposed to a regular voltage amplifier which takes an input voltage and outputs a proportional voltage.

The SATRI "amplifies" the signal by shoving its output current through a resistor.

If you're familiar with Ohm's Law, you'll know that voltage is equal to current times resistance. So if you have a given current, changing the value of the resistance that current is flowing through will change the voltage across that resistance.

And if you make that resistance variable, then you can use it for volume control.

k


It's really just a current feedback amplifier.

So what's really so special about it?
 
Aug 27, 2009 at 3:54 AM Post #23 of 63
Does Krell actually has any patents on CAST or just a copyright on the name "CAST"? If its just a copyright, Audio-Gd can just rename CAST to something else and keep using it. This is what Krell gets for pricing their gear at 10x the parts cost
evil_smiley.gif
 
Aug 27, 2009 at 4:22 AM Post #24 of 63
Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif
It's really just a current feedback amplifier.

So what's really so special about it?


No, it's not. What it is is a transconductance amplifier. Not the same thing as a current feedback amplifier.

k
 
Aug 27, 2009 at 4:23 AM Post #25 of 63
Quote:

Originally Posted by gevorg /img/forum/go_quote.gif
Does Krell actually has any patents on CAST or just a copyright on the name "CAST"? If its just a copyright, Audio-Gd can just rename CAST to something else and keep using it. This is what Krell gets for pricing their gear at 10x the parts cost
evil_smiley.gif



I don't want to start a firestorm, but why do so few people assign any value to R&D? Parts may be cheap, but what about the time and testing that went into developing and marketing the design?

We're not talking about essentials for survival (like the prescription drug business). If it's too expensive, don't buy it. It's still Krell's property and they have the right to price as they see fit.

I think it's fantastic and incredibly generous when people put their designs into the public domain for the benefit of others. I think it's also great when they allow or license others to sell their designs for profit.

I draw the line when a for profit company uses someone else's designs without approval and would never purchase a thing from them.
 
Aug 27, 2009 at 4:25 AM Post #26 of 63
Quote:

Originally Posted by gevorg /img/forum/go_quote.gif
Does Krell actually has any patents on CAST or just a copyright on the name "CAST"? If its just a copyright, Audio-Gd can just rename CAST to something else and keep using it.


Krell claimed to have applied for a patent on CAST, but I can't find any evidence of a patent ever being granted.

"CAST" is a Krell trademark (not a copyright).

k
 
Aug 27, 2009 at 5:33 AM Post #27 of 63
Quote:

Originally Posted by Koyaan I. Sqatsi /img/forum/go_quote.gif
No, it's not. What it is is a transconductance amplifier. Not the same thing as a current feedback amplifier.

k


It's essentially a Current Feedback type amplifier WITHOUT the feedback loop.

The volume is controlled by changing the open loop gain by varying the load resistor on the current mirror output. (CFB types have the resistor here fixed)

So my stand is that the only "bad" thing kingwa did was using CAST as a name for the technology.
 
Aug 27, 2009 at 5:39 AM Post #28 of 63
Frankly, if all the companies that were selling gear to head-fiers who had ripped their designs from other people without permission or credit were to stop then a lot of gear would disappear. Audio-gd has had their designs ripped off as well, with at least one of those rip offs being advertised on the forums. So, how far do you want to take this?
smily_headphones1.gif


Welcome to the world of audio, where very little is original.
 
Aug 27, 2009 at 6:15 AM Post #29 of 63
Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif
It's essentially a Current Feedback type amplifier WITHOUT the feedback loop.

The volume is controlled by changing the open loop gain by varying the load resistor on the current mirror output. (CFB types have the resistor here fixed)


So you have the schematic of the SATRI-IC?

Let's see it and see if you're correct.

Quote:

So my stand is that the only "bad" thing kingwa did was using CAST as a name for the technology.


Kingwa is always conflating CAST and SATRI, and often says "CAST" when what he's talking about is SATRI.

SATRI is a transconductance amp which uses a resistor for I/V conversion.

k
 
Aug 27, 2009 at 6:22 AM Post #30 of 63
My only reference is the SATRI clones Sijosae made eons ago. If they are not a good reference, do you mind showing me the "original"?

For sijosae's clone, they do have that sort of "conversion" I was talking about.

At this point, the only thing left is just semantics?
 
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