ebay:Weiliang Dual X2 AK4399 DAC with LCD

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
terranigma

terranigma

Member
Joined 2007
terranigma

terranigma

Member
Joined 2007
Valeri100 said:
Hi terranigma,
Thank you for a good advise. No I did not make yet good troubleshooting. IT is planned for tomorrow when I will have oscilloscope.
Click to expand...

Excessive load on analog outputs warns with highly distorted sound at first, thus imbalance of sound between left and right. If you didn't observe such thing, you have to check voltages on both analog and digital supply pins of both chips before replacing the dac chip.
 
N

NinoSimona

Member
Joined 2011
Hi Valeri100
terranigma made some good points:)

I checked your pictures. I think the adjustment pin capacitor of analog +5V regulator for left channel has wrong polarity. It's the small 10uf cap of the middle regulator. Please check that regulator and cap.

edit: sorry, it's correct in your version

Nino
 
Last edited:
Sunsun22

Sunsun22

Member
Joined 2004
Polarity of caps

Hi Nino and Val, the caps are correct. Please refer to picture of PCB attached.
 

Attachments

  • PSAK4399.JPG
    PSAK4399.JPG
    183.5 KB · Views: 414
7

730user

Member
Joined 2014
Not quite in the topic.
But for information. I have another mini DAC from Weyliang. PCM1794 +XMOS. He sounds pretty good with the LT1498(I/V) and OPa1612 (filter) operational amplifiers . Who has the DAC PCM1794 - is the best option out of many best operational amplifiers. In addition, he works usb-spdif converter. There is a similar mini DAC AK4399.

But double ak4399 certainly better.
 
V

Valeri100

Member
Joined 2005
Hi guys,
Thank you very much for supporting me with your advices.
It seems that one AK4399 is out of order. Output voltage is +1,8 V on VoutL-, VoutR-, VoutR+ which is not normal (must be +2,5 V) and + 2,5 on VouL+. I have checked that all 3 LT1085 regulators provide +5 V on its output.

I did not checked it on AK4399 pins due to small size of pins and small distance between pins.
I was not sure that I could put oscilloscope probe exactly on pins without short cutting 2 neighbor pins.

I think the described measurements lead to conclusion that AK4399 is faulty. If you don't think so please post your opinion. I'll appreciate it.

Best regards
Valeri
 
N

NinoSimona

Member
Joined 2011
Maybe the IC has died because some loose little chip of solder came between the pins...When I received my assembled PCB, I discovered some little solder threads/spots on the board, due to sloppy soldering. So I carefully removed them, to avoid damage to the components in case of coming loose.

If you are going to solder the new DAC, I would desolder the decoupling electrolytics around it temporarily , to have some more working space with the iron. You must prepare well, you don't get a second chance if the chip isn't aligned well on the pads. I use the aid of a lamp with magnifying glass for this kind of work.
 
V

Valeri100

Member
Joined 2005
NinoSimona said:
If you are going to solder the new DAC, I would desolder the decoupling electrolytics around it temporarily , to have some more working space with the iron. You must prepare well, you don't get a second chance if the chip isn't aligned well on the pads. I use the aid of a lamp with magnifying glass for this kind of work.
Click to expand...

Hi Nino,
Thank you for advice. You are right capacitors are to close to the chip. I will temporary remove it.

I was searching for a good flux. In the past I always was using a liquid one but now I see that most offers are kind of gel lie this one . Is is better? Is it good enough for soldering such kind of chips like AK4399?
 
R

risperdal

Member
Joined 2007
Originally Posted by Sansun22
Using the UTO output is much more superior to any of the opamps I tried - including those discrete opamps like DEXA, Op01 and HDAM. Yet, I also noticed that the Op01 and HDAM are using newer jfets like K246, J103, K30A etc. that; as alleged, not the best jfets. Since I am still having 1000+ of K107 and J74 that I bought 6-7 years ago; both GR and BL grades, I will change them and see if these two discrete opamps can perform better with the swap.[/QUOTE]


Hi Sunsun22,

How did you changed the J FET´s on the HDAM?

Q6 K246>>>K170
Q7 J103>>>J74
Q1 K30A>>>?
Q2 K30A>>>?

Thanks in advance.
 
Last edited:
K

keres

Member
Joined 2010
risperdal said:
Originally Posted by Sansun22
Using the UTO output is much more superior to any of the opamps I tried - including those discrete opamps like DEXA, Op01 and HDAM. Yet, I also noticed that the Op01 and HDAM are using newer jfets like K246, J103, K30A etc. that; as alleged, not the best jfets. Since I am still having 1000+ of K107 and J74 that I bought 6-7 years ago; both GR and BL grades, I will change them and see if these two discrete opamps can perform better with the swap.
Click to expand...

A link for uto output?

Inviato dal mio SM-N9005 utilizzando Tapatalk
 
N

NinoSimona

Member
Joined 2011
Valeri100 said:
...
I was searching for a good flux. In the past I always was using a liquid one but now I see that most offers are kind of gel lie this one . Is is better? Is it good enough for soldering such kind of chips like AK4399?
Click to expand...
Hi Valeri100
I use liquid flux too, but I can imagine the gel type of flux helps a bit to keep the chip in it's place. I remember seeing a utube video where it was used for soldering SMT components.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom