Hi, it could be the NOS thing you used? Try putting original chip back.
If it still doesnt solve the issue you will need to double check every single joint.
Your saying the noise is not there at low volumes? You sure its the DAC thats the problem?
If it still doesnt solve the issue you will need to double check every single joint.
Your saying the noise is not there at low volumes? You sure its the DAC thats the problem?
Hi Mr @dj_holmes , thank you for the tips. The white noise is high at the full line output. For some reason only on. The right side though.
I tried replacing the non over sampling with the saa7220p/b. Still same issue.
I then tried improving the solder joints… the pcb is one of the worst and the most fragile solder pads I have ever worked with!!! They lift out of the pcb with little force. I had to develop gentle hands and use better technique. Originally used wbt solder but it didn’t flow well so the joints were decent…. I then switched to cardas solder and that flowed a lot better…more solder separation between the solder pads.
About 25% less white noise after that.
Like a true crazy person - I also have another Arcam delta black box - I switched out all the regulators except for the -6V with Newclassd. There were some white noise, but much lower than sparkos …
Maybe discrete regulators aren’t all that better than IC regulators? Do you think they are more susceptible to electrical interference?
I tried replacing the non over sampling with the saa7220p/b. Still same issue.
I then tried improving the solder joints… the pcb is one of the worst and the most fragile solder pads I have ever worked with!!! They lift out of the pcb with little force. I had to develop gentle hands and use better technique. Originally used wbt solder but it didn’t flow well so the joints were decent…. I then switched to cardas solder and that flowed a lot better…more solder separation between the solder pads.
About 25% less white noise after that.
Like a true crazy person - I also have another Arcam delta black box - I switched out all the regulators except for the -6V with Newclassd. There were some white noise, but much lower than sparkos …
Maybe discrete regulators aren’t all that better than IC regulators? Do you think they are more susceptible to electrical interference?
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Very nice! LOL
If the problem is only on CD output not line then it must be isolated to the CD output? But from what I've seen only a few resistors seperate it from the 2 different outputs.
If the problem is only on CD output not line then it must be isolated to the CD output? But from what I've seen only a few resistors seperate it from the 2 different outputs.
yes of course. Theres normally a cap before the regualtor and after. Are you not looking at the schematic?
I still havent resolved this issue.
So far:
I've swapped every single transistor (I'm certain) with working channel and still same.
I changed all the electrolytic caps with other channel and still same
I measure every single resistor and same as working channel.
I measure all transistor inputs and outputs voltage and its the same. I have the measurements on a piece of paper if it helps.
I changed all power diodes for analogue and digital and its the same.
If I place my finger on R4 the humming stops.
I have a cs8412 card I attached directly to the DAC chip and it still hummed (I have another post in relation to the input card if anyone is interested)
Its not the caps around the DAC or the film caps .22k
I did notice that if I enabled the phase button the noise completetly stopped.
I can't even get my Rigol DS1054 to pickup the noise!?!?! Its a hum that is very loud perhaps a 50hz hum?
Ive checked every single solder joint and tracks and did not find anything abnormal. I've been trying to fix it for 8 months+
Any help apprectaited. someone has mentioned some component is acting like an antenna.
Just a reminder that I shorted the main power transistors to the ground which leads to R212, which was a bit toast. Then the hum started.
Thank you!
So far:
I've swapped every single transistor (I'm certain) with working channel and still same.
I changed all the electrolytic caps with other channel and still same
I measure every single resistor and same as working channel.
I measure all transistor inputs and outputs voltage and its the same. I have the measurements on a piece of paper if it helps.
I changed all power diodes for analogue and digital and its the same.
If I place my finger on R4 the humming stops.
I have a cs8412 card I attached directly to the DAC chip and it still hummed (I have another post in relation to the input card if anyone is interested)
Its not the caps around the DAC or the film caps .22k
I did notice that if I enabled the phase button the noise completetly stopped.
I can't even get my Rigol DS1054 to pickup the noise!?!?! Its a hum that is very loud perhaps a 50hz hum?
Ive checked every single solder joint and tracks and did not find anything abnormal. I've been trying to fix it for 8 months+
Any help apprectaited. someone has mentioned some component is acting like an antenna.
Just a reminder that I shorted the main power transistors to the ground which leads to R212, which was a bit toast. Then the hum started.
Thank you!
Attachments
I just went through a similar fiasco w/ many of the same symptoms. Two weeks of my undivided attention, tons of unnecessary parts changes, incorrect hypothesis, etc. Bear in mind, I did not cause the problem (sizzling, popping in audio, mostly left channel), it seems to have come on (or worsened) over time. The eventual tip off was the fact that the noise eventually seemed lessened/improved the longer the unit stayed on, which I sadly wasn't noticing/ focused on in the beginning, since I was re-powering frequently. In my mind, only two possibilities: Something affected by temperature and/or something related to capacitance. i.e. slowly charging/discharging/etc over time. When the unit was fully warmed up (not much sizzle/pop), grabbed a can of freeze spray and started shooting, Eventually narrowed it down to an AK4393 DAC. Froze it and the sizzle/pop returned with a vengeance. Layed the tip of my soldering pencil on the plastic chip case, and the sizzle/pop slowly disappeared COMPLETELY. Thought it might be a cold joint. Re-soldered. Same. Waiting for a replacement DAC now. In 50+ years, first time I've ever encountered a "reverse" thermal failure. Toughest thing I've ever troubleshooted. Barked up a forest of wrong trees. Of course, I had no schematic, had to create one from scratch with a continuity tester. Hours of fun 🙂 Hope this helps anyone.
I already tried a different Dac chip. I'm going to dig it back out and look at the joints again. I tried so many things already
Bummer. I wasn't so much calling out your dac, as much as thinking that some (perhaps distant)component became thermally/electrically unstable as a result of the short. I feel your pain. Yesterday morning I was ready to throw in the towel on my fight. If I understand correctly, your device also quieted down some after it warmed up? At any point, did you use any component cooler spray while monitoring the audio? Disclaimer: I don't know if that kind of shock cooling can damage good components. I'd think MAYBE. But we're talking last ditch efforts here. I'd spray everything everywhere. Not just where you think you did damage. It would not be the first time I've seen coincidental, seemingly non-related failures that kept my attention/efforts focused in the wrong place. The universe can be sadistic that way 🙂 . Hope you sort it out. Really blows to throw so much time/parts at a problem and still have no solution. Most of us been there/done that.