Post Go back to editing

Analog Devices AN-207 does not work. Funny problem.

I implemented this circuit in my Marantz CD75 CD player with AD1851's on a separate PCB.
I got a crashing sound in the "stopped clock" channel.
It sounds like CRASSSSHHHH. I also also tried AD1856's DACs and the problem got worse. (needed to make a -5V supply for pin 8)
In total despair I replaced the DAC chips by Burr-Brown PCM56 and everything is fine. WEIRD!

I used HC logic for the interface.

Parents
  • Hello quirck,

    Wow, you are really digging up some gems from the past!

    If the timing is slightly off you will not latch in the data at the correct time and so all sorts of interesting things can happen like a loud hissing sound. You are most likely using fly-wires to connect the two boards and those can cause reflection and timing issues. So obviously, something was off and would require some study to figure out. Look at it carefully on a scope to see what the timing is. The circuit in the App Note would have been tested back when it was written so it should work.

    Dave T

Reply
  • Hello quirck,

    Wow, you are really digging up some gems from the past!

    If the timing is slightly off you will not latch in the data at the correct time and so all sorts of interesting things can happen like a loud hissing sound. You are most likely using fly-wires to connect the two boards and those can cause reflection and timing issues. So obviously, something was off and would require some study to figure out. Look at it carefully on a scope to see what the timing is. The circuit in the App Note would have been tested back when it was written so it should work.

    Dave T

Children
No Data