AUDIO PC: THE USB CARD

[rickmcinnis]

Any chance of more detail on this?

A close-up of the cards add-on wiring?

Where are the USB ports? Why the extension? Why not place the battery at the card?

That's enough questions for now.

Take care,

[nige2000]

this particular card i made for one of the guys here its to suit their requirement
you could put the battery inside the case with a switch or relay

heres my original post on build a pc thread
viewtopic.php?f=15&t=1494&start=2070

the usb port is plain to see in the pics???
ill add in the other pics too

[rickmcinnis]

I thought this one was different or better.

I see now.

What do you recommend to replace the crystal - what are you using?

Thanks,

[nige2000]

heres another card

[rickmcinnis]

nige2000,

Sorry to be dense - I see where you have removed the stock crystal. So where is the replacement?

Is what looks like the USB jack the USB jack? It sure looks complicated if that is what it is. Or is this where you have inserted the "good xo"?

If the above is for the better xo you are using the stock header to attach the USB jacks, is this correct?

[randytsuch]

So I would guess the 4 pin connector is for power. Looks like you bring in +5 and +3.3V? I know the card needs 3.3, and it looks like you connect to +5 on the molex.

And the blue wires on top are USB?

I see the replacement oscillator standing on end but it's hard to tell how its connected. I think you soldered the output and ground directly to the board, and bring VCC to it with a wire, but hard to see in the pic.

Nice work.

Randy

[nige2000]

Randys got it right
there all more or less the same design
Do I need to take more photos?

[randytsuch]

Randys got it right
there all more or less the same design
Do I need to take more photos?

I think a close up of the oscillator would be nice.

BTW, you might want to add a ceramic cap across VCC and ground at the oscillator pins. If it was me, I would throw a 1uf and a 0.1uf cap there.

I used the 4 port USB card because I didn't want to wire USB like you did, but I wonder if the two port sounds better?

Randy

[nige2000]

I knew someone was gonna ask about the clk caps sometime
There's a cap just were the power arrives on the board
I have tried several small value r's just at the clk I didn't find any that improved the clk signal on the scope for some strange reason it put a strange skew on it
The best consistant results were without so i omitted this last cap which is normally standard procedure
just one of the many quirky things I just don't understand

I have noticed possible drops in preformance with caps all over the lifepo4 pc system so always should test with and without :)

[randytsuch]

That does seem strange, but if you tried it and didn't like the effect, I can't argue with that.