Digital Data Inversion And Adding Question.

[mrfeedback]

Old amplifiers provided pre-amp switching that allowed Stereo, Stereo Reverse, L+R Mono, L Mono and R Mono.
Anybody have any circuits handy to do this in the digital domain before the DAC stages ?.
Polarity inversion of the data immediately before the DAC is required too.

Eric.

 

[Elso Kwak]

Old amplifiers provided pre-amp switching that allowed Stereo, Stereo Reverse, L+R Mono, L Mono and R Mono.
Anybody have any circuits handy to do this in the digital domain before the DAC stages ?.
Polarity inversion of the data immediately before the DAC is required too.

Eric.

Hi Eric,
I will only answer the last question:
http://db.audioasylum.com/cgi/m.pl?forum=tweaks&n=60815&highlight=elso+inverted+data&r=&session=
I you happen to use the PCM1704, data can be inverted by the voltage at pin 10 (high or low)😎

 

[bigparsnip]

I think what you would need here is a good bit of DSP as I doubt you will be able to find dedicated chips to do that sort fo thing, sen as how easy it is to do once the signal has been converted back to an analouge one. But, if anyone want to prove otherwise, I would be interesrted in finding out.

 

[mrfeedback]

Hi Elso,
Thanks for the info and links.
I'll study up and see what I can come up with.
My thoughts are towards a pcb that will to the Stereo/Reverse/Mono/Inversion switching and reclocking as an interface between reciever/decoder and output DACs.

Eric.

 

[rfbrw]

Hi Elso,
Thanks for the info and links.
I'll study up and see what I can come up with.
My thoughts are towards a pcb that will to the Stereo/Reverse/Mono/Inversion switching and reclocking as an interface between reciever/decoder and output DACs.

Eric.

Out of curiousity, do you have an actual use for such a board?

ray.

 

[fdegrove]

LESSEE...

Hi,

Out of curiousity, do you have an actual use for such a board?

Pro Audio use?

Cheers,😉

 

[rfbrw]

Re: LESSEE...

Hi,



Pro Audio use?

Cheers,😉

I was talking to the engineer, not the oily rag.

 

[fdegrove]

Hi,

I was talking to the engineer, not the oily rag.

Interesting response.

And saying I was only trying to save you the wait for a reply from the grandmaster himself...


Thank you for your politeness,🙄

 

[rfbrw]

The grandmaster will either reply or he won't. Given the LESSEE at the head of your post, you were asking for it.

ray.

 

[fdegrove]

Hi,

Given the LESSEE at the head of your post, you were asking for it.

There must be some connotation(s) that I must be missing...

Just goes to show how ignorant I can be when it comes to slang...obviously we don't all speak Chinese either. 🙄

Lessee wassup,

 

[mrfeedback]

From The Chief Cook And Bottle Washer...

Out of curiousity, do you have an actual use for such a board?
ray.

If I had one I would put it to good use !.

First off, I want polarity inversion previous to the DAC so that I can flip polarity from my sofa, instead of having to get up and swap the cable polarity at the speakers every second track.
I could do it in analogue, but I have read comments that inverting VS non-inverting opamps sounds different.

I would like Reverse switching (from the sofa) because I have found some recordings to sound more correct when reversed - I do not think that this is a room dependency.

I also figure that switching to mono modes is useful for checking entire system channel matching (null testing), and for having a close listen to one source channel on one or two speakers.

Since posting this thread, I have found that the WM8740 DAC chip will do Polarity Inversion, Stereo/Reverse, 2 ch L mono, and 2 ch R mono.
The WM8746 will do these with the addition of L+R 2 ch mono, and individual channel mutings.
This is one solution, but I am also keen to have these features on a retro-fittable pcb.
Reclocking sounds like a sensible further feature whilst I am at it.

Any inputs ?.

Eric.

 

[rfbrw]

Any inputs ?. Well sort of.
I have a wire-wrapped FPGA board with a CS8412 on it. It currently demultiplexes or converts any of the CS8412 formats. It would not take much to implement the functions you require in a board built along these lines.

ray.