Num Optical to Analog Cinch Audio adaptor

**RedGTiVR6** · 02-07-2006, 02:22 PM

Originally Posted by coucouillu

Thank you Red GTI VR6 and 3onDubs for reply,

The alpine could be a solution.

Bur there are many features that i will never use on it for this price( could be reomte via Alpine touch screen displays, etc...).

Would rather find a little CHEAPER (because the alpine is from AlpineF#1Status!!!!) adaptor like Asian could do...but never found.

the alpine is from F#1 status? hu? the H900 is the F1 status piece, not the 701...

sure, the alpine does a lot that you don't need, but you also don't have to use it all...honnestly, the piece would probably cost the same if it had those functions built in and if it didn't...it's mostly just software coding...

I use very little of the 701 features, but it's WELL worth it still.

**3onDubs** · 02-07-2006, 02:58 PM

You should search for an Alpine PXA-H510. It will have less features than its older brother, the H701, but it will still do what you want for a much cheaper price.

**lchatela** · 02-08-2006, 03:05 AM

For the h510 (like for the old h600), I think it will need an alpine HU to activate the toslink input. Am i wrong?

**RedGTiVR6** · 02-08-2006, 07:57 AM

you will need the display at least I believe, whether it's a head unit or the processor display

**coucouillu** · 02-08-2006, 03:27 PM

You all seen that alpine it is not the best solution...expensive, features don't needed, ..need a alpine display ???...To much much question than responses from my question....

my dream would be like this :

but with all RCA output, not only the coaxial output; little case, no brand (so cheaper than alpine)...and simple features.

**coucouillu** · 02-08-2006, 03:30 PM

Originally Posted by lchatela

There is perhaps a way by building your own DAC (I have seen some project for home conversion, It may works in a car too).

I have searched for hours but nothing!!!

Where do you see these projects???

I have all the equipment to do my own but haven't got any scheme on any project....

you would help me a lot if you remember where you found these projects

.

**coucouillu** · 02-08-2006, 03:37 PM

Originally Posted by Red GTi VR6

the alpine is from F#1 status? hu? the H900 is the F1 status piece, not the 701...

You're right. On the frenc Alpine website is wrotten "Inspired by the AlpineF*1Status serie"..

Originally Posted by Red GTi VR6

honnestly, the piece would probably cost the same if it had those functions built in and if it didn't...it's mostly just software coding..

Haven't really understood what you meant...

**lchatela** · 02-09-2006, 03:39 PM

I have found a french site on that (but don't know the price of composants... it is perhaps not interesting).
I look for 'DAC diy' in google
It seems not to be easy and...perhaps not cheaper than a commercial solution (all project are audiophile oriented):
In french
http://www.ptsoundlab.com/sources/dac/dac.htm
http://www.ptsoundlab.com/forum/view...&highlight=dac

or
http://www.geocities.com/rjm003.geo/...o/diy_dac.html

or
http://sound.westhost.com/project85.htm

cheaper:
http://www.ecp.cc/gud.html

**coucouillu** · 02-09-2006, 06:20 PM

thank you very much lchatela

this one seems to be the best that I could exploit :
http://sound.westhost.com/project85.htm

It doesn't seem very simple

**coucouillu** · 02-09-2006, 06:21 PM

D/A Converter

The D/A converter consists of two main components: the receiver, and the DAC. The CS8414 is a S/PDIF "decoder" that features a built-in balanced RS422 S/PDIF receiver (which is compatible with both COAX and TTL - for TTL, R1 must be removed). It splits into stereo, recovers the sample rate, and connects directly to many DACs using only 3 or 4 pins. It does not require a microcontroller (unlike many others) which makes it ideally suited for this project. Read the spec sheet from Crystal for more information - there is a lot of it. I have shown probably the simplest way to use this IC, as it can be used as a starting block for more complicated designs. Unused pins are not shown - refer to the data sheet for complete pin information.

* Note that C1 (according to the datasheet) is not required, and may be a short circuit to ground. Randy's circuit uses it and it works fine (and it also eliminates ground loops), so it is up to the builder to decide whether to use it or not. For a TTL input, R1 should be removed, and a short to ground used instead of C1.

Figure 2 - Receiver and DAC

The actual DAC is an 8-pin Crystal CS4334. It features 128-512x over-sampling which allows simple 1st-order lowpass filters to be used at the output, if desired. Internal analogue filters and a switched-capacitor DAC are used, so output filtering is not quite necessary, but it helps to reduce noise even further. Audio up to 24-bit and 96 kHz is supported, making it very versatile. The schematic shows how easily this DAC is connected to the CS8414 receiver. R11 and R12 are required if output relays are used, to prevent annoying "pops" when the relays activate by keeping the output at ground potential. These resistors can be increased if desired, although will not be as effective.

There are countless other DACs that could be used instead of the CS4334, providing better S-N and dynamic range (up to 120dB!), although none is quite as simple. I recommend the CS4334 for the first-time builder as the noise figure is acceptable, especially when compared to that of most DIY amplifiers. The maximum output is about 1.2v RMS.

Not shown (but absolutely essential) are the bypass caps from the analogue and digital supplies to ground on both ICs. These should be 100nF ceramic types for best high frequency performance. Make sure that the digital supply bypass returns to digital ground, and the analogue bypass goes to the analogue ground! The CS8414 makes this easy for you, since the digital bypass goes between pins 7 and 8, and the analogue bypass goes between pins 21 and 22. The CS4334 uses pins 6 and 7, and needs a 100nF ceramic bypass cap, with a parallel 1uF electrolytic.