117 replies to this topic

[hanzibal]

It seems that spotify can't licence in Australia at the moment. The music powers that be dont want any competition.

That's a pitty because it's a lovely music service. For about USD 14 per month I can listen to most stuff ever produced in modern time.

Most record companies are signed up here and some of the major ones are even part owners and I think they all make money too. This is really the music industry business model upgraded to cope with reality of today.

So what you think about the crystal wave form then?

EDIT: Here's a video showing what happens to the crystal signal when the chip suddenly de-asserts !sspnd. The red LED indicates !sspnd - keep an eye on the crystal when the LED suddenly turns blue:
http://www.youtube.com/watch?v=VWudNDv1NtI&context=C301fe02ADOEgsToPDskLvEzUHp9kyReYAorSKPVbM

[Magpie]

Sorry Hanzibal

I can't see anything that could be the cause of this problem, that hasn't been mentioned already.

Did you check ALL your ground pins have good contact with ground?

Here is an oscillator that looks similar to yours

My link

The only other thing I can think of is can you move the components on your breadboard to get a similar behaviour? This again would be a lot of effort for little chance of success.

[hanzibal]

I can tell that guy is really proud of his "active FET probe". I'm using a regular passive 1x probe which is probably introducing capacitance to the circuit but behavior is the same even without the probe being attached.

Or maybe I've stumbled across the Heisenberg's principle of uncertainty

I'll go over the ground points once more.

[hanzibal]

Attached an amplifier board over I2S and the board's been working for more than 4 hours straight and counting now. Again, it's a stormy night however no thunder this time

If this continues to work over night, I will include 1M pull-down resistors on each of the four I2S lines in the final design of this mid-way board and probably go back to 33pF crystal load caps - but only after having tested that setup thoroughly

Hopefully this will mark the end of this trouble shooting story cause it's getting kind of old.

[Magpie]

Sorry, I must have missed something. You found the problem? Congratulations if it's true.

[hanzibal]

Wise from previous occasions having called out Heureka, I'll save the champagne for later but it seems like I'm very close now

[carb]

Wise from previous occasions having called out Heureka, I'll save the champagne for later but it seems like I'm very close now

IT'S ALIVE! Congratulations.

A good beer sounds better than champagne anyway.

I'll keep my fingers crossed,

Chuck

[hanzibal]

Like I said, hold yer horses there na boys, cuz it aint over til the fat lady sings

EDIT: Still, so far I've pretty much only managed to create a simple USB sound card with IR remote and headphone jack, i.e. similar to the kind of stuff you can get on the street for 10 bucks The real challenge probably comes in designing the amplifier board to go with it. Currently I'm sending I2S to a Texas EVM and I have an LPF connected to an active subwoofer. Sounds great though

Thanks guys!

[hanzibal]

The board's been playing all night long so I think it's now safe to say that it works

Lesson learned: Never leave any pins floating!

Finally some love from this board!

[Magpie]

Good work Hanzibal I guess the music must sound even better after all the trouble and effort it's caused.

[hanzibal]

You bet it does!

[hanzibal]

I'm currently working on a new version which should not be flawed like the current one is. This time I'll send the Gerber layout files to MakePCB and see what their service is like. Here's a demo video of the board that also utilizes an amplifier add-on:

[Magpie]

Looks great Hanzibal If you can waste an extra bit of time, you might want to put a nicely done graphic on the silkscreen with a picture of a "Frankencat". Maybe something like a cat with bolts in its neck and a bit of lightning nearby. You think I am joking, but I am not.

[hanzibal]

Thanks, sorry for the delay, just got back from a week's vacation in France and Italy. I would love to have a logo of a "Frankencat" and started thinking in line with your suggestion. I'm not much of a router but still considering to maybe integrate the amplifier on the same board, I mean it's kind of scares now plus there's two sides to play with. Could be there's not much room for a logo then even if I go up to 100x80mm which is the limit of the free version of Eagle. What you think?

[Magpie]

Thanks, sorry for the delay, just got back from a week's vacation in France and Italy.

I would love to have a logo of a "Frankencat" and started thinking in line with your suggestion. I'm not much of a router but still considering to maybe integrate the amplifier on the same board, I mean it's kind of scares now plus there's two sides to play with.

Could be there's not much room for a logo then even if I go up to 100x80mm which is the limit of the free version of Eagle.

What you think?

I guess it wouldn't be good to make the board size bigger just to fit a logo, but maybe just fit whatever you can.

Also I think you should watch the separation of the power stage and the preamp stage, to make sure you don't get inadvertant feedback and hum.
It's been a while since I considered these problems, and sometimes they are not really problems at all.
I am just mentioning the following as a possibility, it is a bit of extra cost and complication.


I think what proved to be the best strategy for noise immunity was to connect the power and common as a star, back to the main power section, and pass the analogue signals around as balanced signals.
Balanced signals are balanced around the common voltage rail.

eg Unbalanced
wire 1. common 0 volts
wire 2 signal 1 sin(wt) volts.

Balanced
wire 1. common 0.5 sin(wt) volts.
wire 2 signal - 0.5 sin(wt) volts.

in either case the signal level is the same but the balanced system has more noise immunity.
I don't think you really need to go this path, but I am sure that most high end equipment uses this type of interconnection whenver possible, between boards and between devices.

[hanzibal]

I totally agree that balanced signal transfers are superior. The only analogue signal path is from the internal DAC of the USB chip to the headphone jack, the rest is purely digital until just before the speaker terminals. The amplifier directly accepts I2S (24 bit @ 192kHz max).

[Magpie]

I guess I just have my head stuck in old world analogue electronics.

[hanzibal]

Actually, one could say that the sound never becomes analogue but because the speakers act as kind of a physical filter and how the human ear works (energy integral I think), we can't really tell the difference.

Of course there are some other filters before the speakers but it is PWM nevertheless and so basically you yourself are part of the DAC

EDIT: I guess any analogue signal can be described as digital one with infinite resolution and infinite sampling frequency.

[Magpie]

Hi Hanzibal
I saw this video about a few tips for do it yourself production. Might be useful.

I think I might get an oven like his.
Mikes Electric Stuff

[piwi]

Hi There,

would be nice if the vid contains none blocking content. Can't play the video at all !!!

can you be so nice and produce one that can play in Germany too !!!!

thanks