Wadia DAC 12 Help Needed

[delory]

Hi guys,

I am having a slight problem with a Wadia DAC 12 which I would really like to fix. There is an intermittent crackle coming out of the speakers whether or not the music is playing. Happens on all inputs, opt, xlr, etc.

Worked fine before purchase (I heard it) so something mush have come loose during delivery. Opened the top and checked everything was connected ok, also tried pressing on the chips while in use to see if anything was loose but no change. Can anyone suggest (to a non-electronically minded person) any things I can try to to try and locate the problem?

I've attached a pic so you can see the workings of the player.

All help appreciated.

[ash_dac]

Originally posted by delory
Hi guys,

I am having a slight problem with a Wadia DAC 12 which I would really like to fix. There is an intermittent crackle coming out of the speakers whether or not the music is playing. Happens on all inputs, opt, xlr, etc.

Worked fine before purchase (I heard it) so something mush have come loose during delivery. Opened the top and checked everything was connected ok, also tried pressing on the chips while in use to see if anything was loose but no change. Can anyone suggest (to a non-electronically minded person) any things I can try to to try and locate the problem?

I've attached a pic so you can see the workings of the player.

All help appreciated.

How long before the crackle appears ?

Maybe a component has become temperature sensitive (possibly one of the DACs).

Do you have any freeze spray ?

[Bernhard]

Originally posted by delory
the workings of the player.

is that all ?

[QSerraTico_Tico]

Perhaps the legs of the ICs in the sockets are oxidized. Try pulling out and inserting again to restore good contact.

[delory]

Hi,

crackle appears after about 30 seconds, and then slowly gets progressively louder so what you are saying does make sense. Freeze spray??

As for the ICs, good suggestion, but I tried that at the weekend. No change.

[martin clark]

Are there any electrolytic caps in there, especially coupling? You can get noises if these go 'leaky' (increasing DC leakage current) as they age.

If teh crackling is the same out of Both channels (sounds like 'mono'), I'd look for something common to both eg the PSU as a source of the problem.

[Bernhard]

Originally posted by delory
Hi,

crackle appears after about 30 seconds, and then slowly gets progressively louder so what you are saying does make sense. Freeze spray??

so something mush have come loose during delivery

You say it yourself..., did you check solder joints of regulators and all transistors that might be on the pcb ?
Free standing regulators and transistors tend to desolder themselfes because they get too hot, sometimes even when they are fixed on heatsinks. One of them might be totally loose after transport.

EDIT: I should have looked closer to the picture everything seems to be fixed and double sided pcb...
But I heard that Wadia sometimes have bad solder joints.
The regulator with the black heatsink or one of the three big light blue resistors ?

I think it is not the DAC chips or behind because it is on both channels.

If you have no freeze spray you can also try the other way.
Put the dac outside for 10 minutes so that everything is real cold (does it take longer until noise appears ) and try to heat partially ICs and all other parts with a hair blow dryer.

[Bernhard]

You could take the output signals of the CS8412 and feed into another DAC to see if there is still crack.
Also could you skip the DF and the Xilinx and have fun with non os*.

*feed the signals from CS8412 to AD1864