[fatty]

Hi Jim,

One of the best products you ever built was the Chime. It marries all of the good stuff you developed for the phono stage and preamp products with the digital world. This product sound absolutely fantastic !! I know because I built one.

However, the digital world has changed dramaticly in the last 5 years. Most notably is video( Blu-Ray). But the other thing is the much improved audio on the HI Rez portion of these video discs. Most of these discs are processing the audio at much higher bit rates than 44k. It seems that 96 to 192k is the norm now. These higher bit rates sound fantastic ! They will get you so much closer to analog than any other digital format previously available. In most cases they sound as good or better than SACD. Another thing that has changed is the cost of these video players has crashed ! You can buy a Blu Ray player for $129.00 and most of the big mfgs of these products don't even sell the previously available high quality players anymore ! These video players process video absolutely fantastic. The one thing they also have in common is that audio sounds terrible ! Even at the higher bit rates because they have cut corners to get to the lower price point. The saving grace is that they all have a digital SPDIF output jack that will allow you to hook up a out board audio digital processor. I purchased an OPPO and the audio was so bad that I purchased an out board audio processor that would handle the higher bit rates and the audio was at least listenable--not as good as the Chime but passable.

The MFGs of these cheaper players also know that the audio is bad and to fill in this gap they are making upgrades to these players dedicated to the audio sections. The up charge is any where from $500 to $1000 and they still don't sound as good as the Chime ! But because the Chime is limited to 44k, I can't use it with these higher bit rates. 

This sounds to me a great chance to fill in this gap with a higher bit rate Chime !!!

PLEASE----consider this opportunity !!!!

[poty]

I can't say for sure and do not have so huge practical knowledge as JH, but it seems your goals are not feasible to do.
In nowadays market there are a lot of receivers which do the DAC brilliantly. On the other hand - the bitrate (and so - frequencies) of the modern digital links (HDMI stream, for example) are approaching 10Gbit/s and even more. At this frequencies the DIY gear just does not seem to work.
The second consideration - is parts' base. Even Chime was used ICs for DAC. The proposed device will have to use ICs available to the buying, so the chance is very small to get audiophile core. Several technologies use some kind of coding, which raises questions about supporting a great number of music signal sources.
While SPDIF in its modern state allows to deliver 2 channel of 192 kHz/s bitrate it lacks supporting of enough bit-depth (up to 20bit only), so this kind of device will be even more limited.
I do not speak now about fully built devices, which can be factory-built by JH ideas. This is feasible.

[hagtech]

It is a good opportunity - but it also takes a lot of development time to keep up.  And the playing field is in constant change with new rates and formats and interfaces.  How to keep up? 

However, the real problem is that I had bought a bunch of songs from the Internet in hi-res and CD resolutions - only to discover "DRM".  In no time at all my songs would not play unless I got back online and went through some sort of license approval.  I PAID for those songs, and the DRM was doing everything it could to stop me from playing them.  My only hope was to burn them to CD and then read back and convert to FLAC.  Then I could play the songs I PAID FOR on my other computers (such as the one I use in the lab for testing).  But that was a total hassle.  I'm sorry, but it totally irked me.  Because of that moment in 2008, I gave up on digital and have not purchased a single digital song or CD since.  Not one.

Instead I put my focus back on analog.  All of my development since then has been for analog circuitry with an emphasis on vinyl playback.  It's a good place to be.  Will I ever go back to digital?  Never say never...

jh

[hagtech]

As fas as 1GHz and high data rates and similar - I am at total ease with it.  In the past several years I have been lucky enough to do a lot of work in that area designing RF filters.  A lot of what I learned folds back into audio.  It may not be immediately obvious, but RF and audio actually have a LOT in common.

Here's a photo of a 75W dual bandpass filter I did that covered the UHF SATCOM region:



And the measured (green) versus simulated (simplified model) responses:



jh