[Freo-1]

I've recently made a discovery that has me questioning high end audio design concepts.

Started off with trying to improve the amp section of a Sony STR DA-6400ES receiver.  The fron end preamp section in this unit is quite good, but the output amp section is run of the mill at best.  So, used the preamp out and connected that to a STR DA-9000ES receiver, to take advantage of the improved amp stage. 

The sound improvement was signifigant, which got me to experiment more.  Eventually, wound up with two STR DA7100ES units running a bi-amp setup. Connected HDMI, i-link, and optical input streams to each of the 7100's.  Connected one 7100 to the 5 LF sections of the speakers, and the other 7100 to the 5 HF sections of the speakers.

The results are nothing short of astounding.  The S-Master Pro accepts the various digital inputs, and routes them to MOS-FETs, through a LF pass filter, to the speakers.  The signal stays digital to the output stage, which  is a class A zero feedback topology. 

This type of setup seems the way to go.  The D/A and A/D conversion is removed with this,  which opens up the sound considerably.  I would think that conneccting digital inputs to audio gear would be the way ahead here.

Sony uses a analog power supply for the class d amp, which provides sufficent power. The folloing link explains how it works:

http://www.docs.sony.com/release/ES_STR_05_Final.pdf

[ted_b]

Get rid of A/D, yes!  In what way does your project get rid of D/A??  It occurs later, but does occur (otherwise we'd be hearing digital).   Great D-to-A is now becoming more and more available, and we're hearing some incredible sounding redbook, a format many said was harsh and unacceptable.  And then there's the onset of hirez!   

[Goosepond]

Years ago I remember seeing some mfg's ads about their "digital ready" speakers. Who needs D/A? 

Gene

[Freo-1]

Get rid of A/D, yes!  In what way does your project get rid of D/A??  It occurs later, but does occur (otherwise we'd be hearing digital).   Great D-to-A is now becoming more and more available, and we're hearing some incredible sounding redbook, a format many said was harsh and unacceptable.  And then there's the onset of hirez!   

In this application, the amp IS the D/A converter (which is the point).  This get's around the limitations of a conventional amp (heat, feedback, etc). as well as elimating conversion errors along the way.

[Telstar]

Get rid of A/D, yes!  In what way does your project get rid of D/A??  It occurs later, but does occur (otherwise we'd be hearing digital).

QFT.