Analogue to SPDIF - converter project opened

dj_stick

travelrec… did you get the email i sent? also could you please send me an email with the components listing, so i can start to find these? thanks again

edit: also, for external purposes, a well shielded cable is better for longer distances than optical… due to distortion and diffusion of the light path

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TravelRec.

Hmmm, never had any problems with the light stream up to 10m with the specified cables and interfaces (intensive testing around, no errors discovered) and know few posts from ppl have problems with coax - finally coax is a galvanic connection over ground - so you have a direct connection with external devices and the nice ground-loop-problem could occur. Optical way is free of potential and (okay, for distances below, say 10m) the better choice, I think. And optical cable is much ceaper , ~ 2,50 EUR / m...

Yes, got your mail - unfortunately I´m in stress here with finishing an album production and working at construction at same time ... You will hear from me, please be a little patient. The parts you need you find in the component positioning layout @ electricstart (target file, print it out or look to the screen at 200% scale) - you need them all thrice, except the oscillator and hc74 / hc00 only once and none of the opticals. For MIDI look at the diagram. Do you want also a THRU-port (and if yes THRU from input and/or THRU from out?)?

CU!

TravelRec.

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dj_stick

only midi i/o i don't need thru
and thanks anyway for this (take as much time as you need)
what about the power regulator? any special components need for that?

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meroveus

Hey TravelRec (and djstick),

I have decided I will do much like what djstick will do.
Forget SMD devices. I had a look at some cards very closely, and observing the almost microscopic resistors and extremely tight pin spacing, decided life isn't meant to be _that_ hard!

I'll do two boards - each Euro size:150 x 100mm. One for the midi ins/out/thrus and the other for audio.
I'll use two panels instead of one to allow plenty of room for lettering etc.

I have been thinking about voltage regulation a great deal. The best way to go, might be to filter and smooth the 12V several times, before passing it through a MAX6350 chip:
http://www.maxim-ic.com/quick_view2.cfm?qv_pk=1700
As you can see, this has _extremely_ low noise and ripple.

The optical link sounds cool, but probably impractical, being best suited to serial communication. The IDE cable allows more than one simultaneous stream.
Cat5 cable being not only cheap, would be probably better than coax, esp for digital data.

I'm still trying to find my way around target 2001/3001.

A THRU from OUT, duplicates the OUT, and a THRU from IN, sends the IN directly to OUT. Have I got this right?

dj_stick

btw im not sure whether the solder tip is small enough
http://www.dse.com.au/cgi-bin/dse.st...uct/View/T1976
that is the soldering station im using currently, the tip looks to be about 2 or 3 mm… is that too large?
edit: i actually read the website and it said 1.6mm for the tip

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meroveus

1.6mm will be fine.
1mm is even better for small components, but such thin tips are only available on expensive production stations and some gas/butane irons.

BTW, don't use the sponge for that drops the tip temp too much. You then have to wait for the temp to recover.
Instead use a tip cleaner which looks like a copper scourer pad stuck in a tin. Can't find a pic at the mo.

dj_stick

i've seen the tip cleaners before… but i also like time to sit back and stretch my back abit (i have a bad back) so the warm up time isn't too bad for me… also what is the best temp to use (in _°C please)

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meroveus

k, tip temp depends upon the solder.
I still have a large supply of the old,bad solder containing lead
For this I have a temp of about 315C when soldering and about 350C when desoldering.
I don't know what the recommended temps are for the new lead-free solder.

TravelRec.

Hi!

I use only a 7809 for pre'filtering' and the 78L05 direct before the circuitry (one for each unit) enclosed with 4 10µ capacitors (tantalum) and 1 100n capacitor (X7R) - that´s working fine and only 3-pin ICs.

My solder station is an old one with temperature regulation, my tip is a long life "ersadur" that I use for about 4 years without any traces of damage. It´s a chisel-type ~ 2.5 x 0.8 mm (4mm dia) and works really fine with standard SMD 1206 / 0805 resistors and capacitors and finally with the standard SMD-ICs type SOIC and TSSOP (I don´t speak about 128 pin microprocessos!). Best temp is about 270 to 300 deg. C, not higher and never longer than 5 seconds to each pin! Or you have some chips to glue on the wall . I use halogenic- and leadfree solder-wire 0.5mm dia. Many problems could lying here so test some different solder wires - if possible. I think it´s also a good idea to test the tip and solder wire with some passive components before soldering the chips - so you are a bit familiar with the handling. And please avoid to heat up the tantalum capacitors longer than necessary - they have some problems with high teperatures and fuctionality...

CU next time!

TravelRec.

P.S. To meroveus: Hey, don´t cry before testing - SMD is cool and has better high frequency response...!

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dj_stick

so my solder station should be fine?
and also are the components used for the power regulator listed in the pcb layout? and are they needed in triplicate like everything else?

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TravelRec.

Yes,

Yes,

and yes, except the 7809, only once - it´s the master regulator


Think, I can send you the layout on weekend...


Greetings!

TravelRec.

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dj_stick

thank you, you can take as much time as you need though

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TravelRec.

Hi dj!

Hey sorry, not this weekend - please check your mail!

TravelRec.

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dj_stick

the online websites of the companies i can order from
www.jaycar.com.au
www.dse.com.au
are lacking several of the components required…
also the 74hcxx IC's are not SMD down here… see here
i'm also having trouble finding the correct oscillator
i haven't yet looked at the other components required… BUT i think if i give a list of components required to my electronics teacher @ school he should be able to find them

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TravelRec.

Hi dj!

That sounds not so fine , the hcxx are as old as the dinosaurs, so it should be able to find them in SMD (got it here at www.reichelt.de, german site only). The oscillator was also a little problem here, found it at www.segor.de (also german site - don´t know if they ship to australia...). Hope your teacher can help you - otherwise we have to meet anywhere ...

Good luck!

TravelRec.

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dj_stick

can the clock be taken from the ac-97 clock on the aud_ext connector? and somehow divided?

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TravelRec.

Hi!

Yes, it could, but the problem is (if connected via flat cable like IDE), that the noise of that wire will interference the next wire, that is the SPDIF#2 input and so this will not work properly anymore. I´ve discovered that while making experiments with my card here. If you will use it: divide by 2 for the ADC and by 4 for the I2S to SPDIF converter IC. This division can be done by using the whole 74HC74, but like I said: relatively unsafe and not tested (finally it seems to work with the LiveDrive...).

Greetings!

TravelRec.

P.S. Hmm, should I rather finish the layout if you got all electronic components...?

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dj_stick

i don't actually have any of the components *yet* i need a final list of what i will need and whether they are SMD or not… i will then find out what *is* available and my need to substitute

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TravelRec.

... quick man, very quick!

Ahem, okay, I´ll send you a list of components for 3 devices in 3 versions and you deceide what you finally want to get or what you are able to get. If there´s no other way I could send you some ICs- but this should be the last way, due to shipping costs...

Greetings !

TravelRec.

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dj_stick

alright - but most likely the non-smd method is probably the only one i can do atm (may be a little hard due to the size of the components vs the size of the area

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TravelRec.

Oh yes, that´s hard, so you need always 3 PCBs 100x160 to hold all the components ... is this really what you want? There [COLOR=orange]MUST[/COLOR] be an other way... What´s with your teacher???

TravelRec.

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dj_stick

three pcb's may be easier for me to solder tho… unless you have an app that can make larger pcb's…
i'll speak to my teacher tomorrow if i can (school is kinda wacked out in exam week) to see what he can find

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TravelRec.

Okay,

I don´t think the app is the problem, much more the size of your computer and it´s drive bay (do you want to have a balcony on it? , just a kind of modding...). Then we will see what your teacher can do for you (except learning and teaching all the time).

Greetings!

TravelRec.

P.S.: last quick-mail for today, have to donate some blood now (other kind of help ) / CU

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dj_stick

my drive bay is fairly deep and i have a considerable amount of space behind

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TravelRec.

Fine, I see, so ask for the parts you know from the project in the net and for all the passive parts, complete list will follow here next!

So far...

TravelRec.

P.S. I´m really away now!

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dj_stick

thanks anyway for the work your putting in to help me

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TravelRec.

Hi!

Here comes the...

Component List for 3 ADC Devices:

Resistors:

6x 150 Ohms Carbon SMD 1206 or 1/4W standard 5% Tol.
12x 1k Carbon SMD 1206 or 1/4W standard 5% Tol.
18x 7,87k Metaloxide 1/4W 1% Tol.
3x 47k Carbon SMD 1206 or 1/4W standard 5% Tol.
9x 100k Carbon SMD 1206 or 1/4W standard 5% Tol.

Capacitors:

6x 10pF SMD 0805 NPO
6x 6.8nF SMD 0805 NPO / X7R
21x 100nF SMD 1206 X7R
6x 470nF SMD 2220N Polyester / Mylar or WIMA
21x 10µF / 16V SMD B or standard Tantalum
1x 470µF / 16V Electrolyte Alu

Coils:

3x 47µH SMD MuRata Chip or standard

Diode:

1x 1N4002 SMD Melf or standard

ICs:

1x Oscillator 12,288Mhz Metal or clock pulse from soundcard (not tested!)
1x 74HC(T)00 SMD or DIP
1x 74HC(T)74 SMD or DIP
3x LM (µA) 7805
1x LM (µA) 7809
3x CS8402 A SMD or DIP
3x CS5331 A-KS SMD (DIP not available!)
3x MC33202 SMD or DIP


Greetings!

TravelRec.

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meroveus

Hey TravelRec,
thanks once again for all your hard work.


djstick:
here's some more Aussie companies you can order components from:

http://www.futurlec.com.au/
http://www.microzed.com.au/
http://www.radioparts.com.au/
http://www.rockby.com.au/

Don't forget, there is always: http://www.rs-components.com.au/ and http://www.farnell.com/ but they are usually quite expensive!

cheers

dj_stick

thx alot travelrec and meroveus i will look for these right away

i'll give the list to my teacher aswell to see what he can find

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TravelRec.

Hi all!

The circuit to convert signals from SPDIF to I2S that I´ve posted at www.electricstart.de works not really properly . Intensive testing yesterday has confirmed it. It seems that the I2S inputs have to be syncronized with the card´s own frequency to work well. If I apply yet an external SPDIF source (47994 Hz, from A/D) with a clean 1kHz sine then a strange repeating click is to hear (like frequency floating), for different sources in different speeds. The closer the input is to 48kHz the slower the click repeating is... If I apply 44,1 kHz input then no click is to hear (I think it´s always there too). I think I have to make further tests with different chips and then I´ll comment my experiencing here. So please do not apply the SPDIF to I2S circuit to your card, before it´s not fully revisited and working. I´ll add a note to my website soon.

Thanks for your attention!

TravelRec.

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