CS4397 dac

[gabdx]

Yes i can post a picture very soon,
regarding the voltages on the supply , i think i have partially fried the little regulators feeding it with incorrect wiring on my china kit transfo, these guy in china didnt gave me any instruction how to connect it ! Since i have replaced it with a wall pack 9 V that really is giving me over 11 volts. Ill try it with direct coupling on the preamp we will see.

[leo]

Toxiccockhead405 is actually my real first name, I just use Iain for forums

Can I call you cockhead for short then ?

[gabdx]

You edited before I posted

I presume this 0.7v DC is what you are measuring at the dacs differential outputs to ground and not on the line out after the op-amp?

Exactly , and it used to be 2.5 V

[leo]

Yes i can post a picture very soon,
regarding the voltages on the supply , i think i have partially fried the little regulators feeding it with incorrect wiring on my china kit transfo, these guy in china didnt gave me any instruction how to connect it ! Since i have replaced it with a wall pack 9 V that really is giving me over 11 volts. Ill try it with direct coupling on the preamp we will see.

Yes, problem with a lot of this stuff is that its usually cheap for a reason, I won't comment on here my experience with certain products made in China

[leo]

Exactly , and it used to be 2.5 V

did you try removing all the links across C27,28,30 and 31 and measure again? this just eliminates any problems on the boards analogue section

Also check the voltage on the dacs onboard U4 SMD regulator, it should be 3.3v

Check for any shorts or track breaks around capacitor C25, this is for the dacs internal bias

Also check the CS4397 analogue supply pin (pin22) it should have 5v going to this pin

[gabdx]

i did mesure again without the links and it give low reading, mostly around 0.4 volts ac or dc.

the 22 pin indicate - 1 V and 21 +1 V, the U4 has 3 pins, 1 to 3 = -2 V
2- 3 = around 1 V.

Imo it looks bad

[leo]

i did mesure again without the links and it give low reading, mostly around 0.4 volts ac or dc.

the 22 pin indicate - 1 V and 21 +1 V, the U4 has 3 pins, 1 to 3 = -2 V
2- 3 = around 1 V.

Imo it looks bad

Hmm, thats not good mate
The onboard 3.3v seems a little low but its that 1v for the dacs analogue which is the main problem.

Set your multimeter to continuity/bleep, turn the dacs power off and measure pin22 to ground, does it measure short circuit or low ohms?
If so you either have a short somewhere on the supply lines or if your very unlucky the dac chip may have gone

[iihay]

Can I call you cockhead for short then ?

I'll wash and then you can drop the toxic

Iain

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Another totally off-topic post from the keyboard of Toxiccockhead405

[leo]

Another thing to check, the small connectors inside the big white plastic plug, those things are really shite in all honesty, I've known the plastic sleeving for the cables can sometimes not be stripped back enough so the metal crimp does not make a good contact with the cable core.
Because my dac uses a different regulated supply to the standard one I removed the plastic socket and fitted something else

[leo]

I'll wash and then you can drop the toxic

Iain

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Another totally off-topic post from the keyboard of Toxiccockhead405

Thats a little bit too much info there mate