X-DAC V3, Help... Please!

[datsun510]

Hi all,

I have a problem with my x-dac v3 and have been looking all over the net for info, then stumbled across these great forums.
Hope it's all right if I make a post...

Anyway, on to the problem.
The dac has power and "works..." as in it will power up and lock on to either the coax or optical signal from the transport;

However, the analog output is garbled. The only way I can describe the sound is to imagine the worst quality AM radio station you can and then imagine that it was clipped immensely.

I tried multiple transports, coax, optical, and the problem is still there. Also verified that the psu has ~14 volts from secondarys and ~7 volts secondary to center tap. Also pulled the case of the x-dac and did not notice anything that looked burned, etc.

If anyone could shed some light on perhaps some things to test, it would be incredibly appreciated!

Regards,
Matt

[XTRProf]

Hi Matt,

Your PSU should not read 7 VAC (not VDC, ok) on the DMM from secondary hot to CT. It should be around 12 to 13 VAC. According to Alex, the guru here, the X-Dac V3 should also work under 15 VAC. So under such extreme low voltage condition, of course, the chips in the dac will not work properly and will sound garbage as you had described. Are you sure you had got a right PSU for the X-Dac V3?

Hopes this helps. Merry Christmas to you and your family.

[datsun510]

Hi XTRProf,

Yes, it's the correct PSU, as I have been using the DAC for about a year now without issue. I'm really new at this but after reading up on CT transformers I thought the voltage (AC) from the center tap to a secondary was approximately half that of a secondary to secondary reading. Oops! Well, that would explain things. Guess I'll be ordering a Little Pinkie PSU!

I can't wait to try some of the mods,

Thanks so much for your time.
Merry Chrismas,

Matt

[XTRProf]

datsun510 said:

Hi XTRProf,

Yes, it's the correct PSU, as I have been using the DAC for about a year now without issue. I'm really new at this but after reading up on CT transformers I thought the voltage (AC) from the center tap to a secondary was approximately half that of a secondary to secondary reading. Oops! Well, that would explain things. Guess I'll be ordering a Little Pinkie PSU!

I can't wait to try some of the mods,

Thanks so much for your time.
Merry Chrismas,

Matt

The X-dac V3 cannot work on 7 VAC hot to CT. You must get 12 to 15 VAC for it to work properly.

Regarding modes, if you are advance enough, SandyK (Alex) xtreme modes thread will up the ante of the MF dac. I'm also studying that right now but will approach it slightly different from what Alex had written.

Please do project what you intend to do to your X-dac v3 so that we learn more from each other.




Cheers to you ............... Ho, ho, ho .............

[leo]

So the X-dac V3 uses an external centre tapped traffo with 15-0-15 secondarys and yours measures 15-0-7 AC ?
Sounds like the traffo has a problem

Are you confident in taking the tops off both units? what I'd do first is connect the units up and measure the traffo when loaded and then try some DC measurements to the dac and and analogue output section, I don't have an X-dac but if your confident enough to take the top off and do some measurements we'll help you the best we can.
Ideally a clear top view pic of both units would help

[datsun510]

Hi Leo,

Just to confirm...
The wallwart PSU that I'm using has 3 pins that look like this:

1 2
3

Between pins 1 to 2 measures 13.5V AC and when I measure from pins 1 to 3 and 2 to 3 measures 7V AC.

It seems that this would be the problem.
But if not, I can take the case off and make some DC measurements. Not too sure where to start measuring though. Will take some photos.

Regards,
Matt

[PinkFloyd]

datsun510 said:

Also verified that the psu has ~14 volts from secondarys and ~7 volts secondary to center tap. Also pulled the case of the x-dac and did not notice anything that looked burned, etc.

Hi Matt,

The stock PSU should be measuring more like 29V between both secondaries and around 14.5V from each secondary to centre tap.

On the din plug probe between both outer pins you should read around 29V. Then probe between the centre pin and each of the outer pins.... centre to outer pin reading should be about 14.5V

Let me know what you're measuring.

[datsun510]

Hi PinkFloyd,

My stock PSU is dead.
I'm interested in ordering a Little Pinkie,
Could you PM me with details?

Thanks,
Matt