Music Server with Improved Apple Airport Express

[merlin2069er]

Cool, I've got a spare flea clock. I've got to find something to do with it.

 

[vitalbesson]

Is it exactly 25 mHz, or 24,576?

 

[Marlowe]

Yes, it is exactly 25MHz. By the way, the output level of the clock should not be over 3.3V. The AAE does not work under the 5V clock or so.

 

[Marlowe]

What are those black and red wires, is this AE power?
Blue and white - are they opened w/o any screen at all?

You are right. The black/red wires are the 3.3V power rail.

The clock wires are twisted and very short. The clock module is placed near the AAE as close as possible. I have also tried the coaxial cable, but the difference is insignificant.

 

[vitalbesson]

Thank you.

 

[vitalbesson]

Just posted this:
Airport Express - is not bit perfect. | Computer Audiophile

What would you say?
Am I right to guess that even if AE has bad clock itself, it would not cause to transmit wrong data values? But we see exactly wrong data values here...

:-(

 

[Roscoe Primrose]

I get a page not found at that link...

Roscoe

 

[vitalbesson]

They just changed the engine there.

Here's the updated link:

Airport Express - is not bit perfect.

 

[longhp]

They just changed the engine there.

Here's the updated link:

Airport Express - is not bit perfect.

The link is removed. Does it mean the Airport Express is bit perfect ?

 

[vitalbesson]

they moving links due to reconstruction

here it is finally:
Airport Express - is not bit perfect.

 

[longhp]

Any thought to modify the new airport express 2012?

Here is the link of new AE is dissected
Rogue Amoeba - Under The Microscope Blog Archive Airport Express (Dual-Band) Disassembly

 

[Nisbeth]

As I recall, the new AXP runs on a single 3.3V rail, so adding a new supply should be first step (and quite easy)

/U.

 

[roliveira]

How can make coax spdif available from the OP airport? May I use 2705's pin5 DOUT directly? Any passive components?

Thanks!
Rui

 

[Nisbeth]

Have you looked at the datasheet for the PCM2705?

/U.

 

[roliveira]

Hi Nisbeth,

Yes, I surely did. The datasheet however doesn't provide much info about the spdif output (ie. couldn't find impedance value for dout).

While a complete noob here I think I can make for a simple divider and pulse transformer stage. My question however was specifically related to the airport express and OP post as it may have been tried and tested a while back (Jan 2009).

Thank,
RUi

 

[Suprted1]

I2S

Did anyone succeed tapping I2S to a external dac with this AE ?
I am considering this to make my ES9018 DIY DAC a wireless dac.

 

[glt]

USB audio output mod: Apple Airport Express USB Audio Output Mod | H i F i D U I N O

 

[qingcai]

I read other article that they are use 50mhz , does 25mhz work?
and where to buy the clock ?

thanks

I would like to share my experience on upgrading the clock for AAE.

There are two SMT 25Mhz crystals under the AAE PCB. The one closer to the IC 88F6183 is about audio.
I removed this crystal (marked as Y700 on the PCB) and its load capacitors (C700 & C701) from the PCB.

And then, I soldered a blue wire to the clock input pad on the PCB and the white wire to the GND on the board.

Finally, the blue wire was connected to the clock output, and the white wire was connected to the clock ground. As a starting point, the clock currently used is a common 25MHz XO supplied by a regulator based on The Flea.

After this modification, the resulting sound is more smooth, more fluidly, and more liveness.
I am planning to try more clocks for the AAE.
TCXO with The Flea and Kwak Clock 7 will be tested in the future.

Simple and effective. Highly recommended.

 

[tomchr]

Did anyone succeed tapping I2S to a external dac with this AE ?
I am considering this to make my ES9018 DIY DAC a wireless dac.

The Airport Express has TOSLINK S/PDIF out. It uses the 3.5 mm jack for this (it's a line out/optical out combo jack). Why not just use that?

~Tom

 

[qingcai]

everybody said i2s has better result than spdif.

The Airport Express has TOSLINK S/PDIF out. It uses the 3.5 mm jack for this (it's a line out/optical out combo jack). Why not just use that?

~Tom