dual 1541DAC non-o/s installation failure

[inn]

hi all,
Would like to seek for your advices/solution to troubleshoot my newly bought DAC kit from HongKong.

Problem#1 :
When 1541DAC are not installed, I can only measure voltage at 8414¡¦s pin7 and 22, 1541¡¦s pin15, 26 and 28. All other voltages at 1541DAC's socket pins are absent. However, I could measured voltages at all other 1541DAC's pins when the 1541DAC are mounted onto sockets.

Problem#2 :
The ¡§LOCK¡¨ LED lighted ON when my CD player is not running, but it lighted OFF when my CD player start playing (Reverse??). I switched over LED polarity, but it never lights ON at all.

PS : I have already soldered 8414 when the above 1541 DAC Voltage measurement was made, wonder if this is the cause of no voltage at 1541 socket pins when 1541 is not installed?

Thanks in advanced for your advices!

[analog_sa]

Problem#1 reminds me of the light-bulb problem: if there is no light bulb in a socket it doesn't shine. Isn't this amazing?


You may actually get some more sensible advice if you at least mention the basic stuff: does it play music or not? Can you post a circuit or a link to the design?

[inn]

hi analog_sa, thanks for replying.
I am not sure if I can post the schematic here as it's a 'commercialised' DIY kit.
I have tried connected the Coax Out from source directly to 1541DAC (Tube Output stage was not used for this troubleshooting purpose) and then to my int. amp, no problem playing music but the output seems to attenuated ~30% (probably due to lacking in drive power since no analog Output stage was used).
My main concern here is that why the LED works in reverse, where it lights ON when CS8414 is not receiving signal and lights OFF when signal is received by CS8414?
Since this is my first DIY DAC, I am not sure if it's normal to measure no voltage at 1541DAC socket pins (except pins 15, 26 and 28) when 1541 is not mounted (all component and CS8414 are installed) onto socket ?
Many thanks!

[Coulomb]

If this is the Tube Lover Dac from Thomas Why don't you ask him at www.diyaudiocraft.com ?

Regards

Anthony

[inn]

I think he's something to busy with
It sometimes take days for him to reply, and I am running out of time to complete this kit (other work assignment) by this 1~2 weeks
That's why I am trying my luck here hoping someone with experience to give some advices.....
Thanks for the link, in fact, I have posted my problem in that forum since weeks ago....

[analog_sa]

am not sure if it's normal to measure no voltage at 1541DAC socket pins (except pins 15, 26 and 28) when 1541 is not mounted

The only pins on the 1543 which actually get some input from the 8414 are sdata, fsync, sclk. In the absence of spdif input i would imagine them to be zeroes; when playing there will be square wave signals.

If you need to invert the indication of the led you should look at the board and notice that one pin of the led goes to a pin on the 1541 while the other (through a resistor) goes to Vcc or gnd. Just swap Vcc and gnd for that pin.

[inn]

Thanks! Will check the schematic and see if the LED connection is inverted.