Ayre Acoustics - Diamond Output Stage

Vintagear

Vintagear

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I was looking at some of Ayre's current offerings like the AX-5 twenty and was surprised to see that they seem to have revived the Diamond Output stage similar to those found in Sansui units like the AU-X19 series & AU-X1.

https://www.ayre.com/products/amplification/ax-5-twenty/#DESCRIPTION

According to Stereophile, Richard Baker of MIT who got the patent "described it as having a number of strengths: It can operate effectively in a floating- or above-ground condition; it can produce considerable power gain; it's reliable; it's fast; and, perhaps best of all, the diamond circuit is simple."... and Charles Hansen (Ayre) acknowledged "those advantages and adds one of his own estimation: that the diamond circuit, used as an output section, simply sounds better."

Any thoughts?
 
I can't so much speak to the technical aspects cited in the excerpt above, but I know Sansui's iteration of this circuit sure sounded good. The only other item of possible interest I can add is that Sansui had a patent on the circuit design, and I wonder if it has somehow lapsed, or if this current offering was licensed from whoever now holds Sansui's patents. I'd figure those were sold off along with any other company assets many years ago now when Sansui Electric Co., Ltd. was wound down.
 
Its a current mirror design, not sure its something they would have patented, perhaps they patented a variation of it and the term Diamond Differential perhaps?
Just guessing, but it is fairly well know topology...
 
I'd have to do a patent search to see the substance of it, but have marketing material somewhere here on the AU-919 and AU-X1 that refers to the DD/DC circuit as something Sansui had patented at the time these amps were being marketed.. The name itself (diamond differential direct coupled) could have been trademarked separately but US patent law doesn't allow patenting of names, only the underlying concepts and technology therein.

Probably a specific and unique variant of the circuit is what Sansui was granted a patent for. These days they'll issue a patent for damn near anything (as seen now in the era of silicon valley behemoths) but standards were a bit higher then for what the patent office would approve.
 
Yes indeed, thinking a little more about it, Sansui may have taken this idea and developed it and got it working where others may have struggled with it.
Sansui really did pick it up and run with it, they made it their "signature" design...
There have been many circuit topologies which were theoretical ideas that became difficult to put into practice, its a win win for whoever can make them work as Sansui obviously did..
 
skippy124 said:
If anybody likes reading Patents - the Sansui patent for the diamond differential circuit can be found here

https://patentscope.wipo.int/search...String=sansui+differential&tab=PCTDescription

I has a very good and detailed description of how the circuit works, has diagrams, claims etc


Cheers

John
Click to expand...

skippy124 said:
And to round it off

the super feed forward patent

https://patentscope.wipo.int/search...String=sansui+differential&tab=NationalBiblio

Elements of the x balanced design perhaps

https://patentscope.wipo.int/search...String=sansui+differential&tab=NationalBiblio

power amp design

https://patentscope.wipo.int/search...String=sansui+differential&tab=NationalBiblio
Click to expand...

From another thread, some Sansui patents

Cheers

John
 
John, thanks for linking that. Didn't really want to spend what was left of my Sunday evening doing patent searches. I'll give them a read later as some bedtime reading. Should combat that insomnia nicely.

This does cause me to ask, as I am not terribly familiar with any Sansui amps post 1986, did they continue to base their amplifier designs on the DD/DC circuit, or was there some further refinement that gained a different marketing name (other than X-balanced which seems to be the successor of DD/DC)?
 
Sansuiman said:
John, thanks for linking that. Didn't really want to spend what was left of my Sunday evening doing patent searches. I'll give them a read later as some bedtime reading. Should combat that insomnia nicely.

This does cause me to ask, as I am not terribly familiar with any Sansui amps post 1986, did they continue to base their amplifier designs on the DD/DC circuit, or was there some further refinement that gained a different marketing name (other than X-balanced which seems to be the successor of DD/DC)?
Click to expand...

Sansui continued to use the diamond differential circuit throughout its later amps, even following the arrival of the x-balanced design onto the scene. It is mentioned in Sansui's advertising literature of the period.
 
^ thanks for that. As stated, my knowledge - other than model numbers and some basic specs - of models made after 1986 is very slim, and I have nothing in terms of marketing brochures for amps in the 1986-2000 era for refer to.
 
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