Experience with this DIY DAC ?

[RichLund]

Hi rhinomite

I have the same transformer (R26-34) and asked Ian Ma advice. He now supplies an R-core transformer instead of the toroid (typical!)

His has different colour wires but he sent me this diagram to help.

In place of the blue - 9V use both blacks (browns not used so snip ends and tie safely in knot)
in place of the yellow - 15V use grey
in place of the brown - 15V use blue
Twist spare grey and blue ends together and connect to middle 0V

I'm in UK so for 240V primary use red for Live and orange for neutral

Then twist ends of yellow and green primary's together to make connection (solder together or crimp)

Connect earth wire (yellow/green striped) to IEC socket if using metal chassis.



Hope that helps

Rich

[lbj]

Originally Posted by rhinomite

Help Please! I'm hoping someone can sanity check my plans for wiring up my IEC connector, R-core (R26-34) and DAC as I'm pretty sure I've got it wrong.

I don't really understand the part about connecting the two 0-15V in series then wiring 15 0-15 0 (or does this mean the 0-15 is actually a blue and grey connected together into the 0V?)

I set Ian Ma a pic of my R26-34 and he sent back the below pic.

In a nutshell, yes you connect both a blue and a gray wire to the 0v.

[lbj]

Keep in mind the above pic is set up for 115v input; for 230v, yellow and green are connected together.

And, as per Bill Fuss, I didn't ground the dac and everything works fine.

[rhinomite]

Thanks so much everyone for helping out with the wiring!

I've attached a picture of the final diagram for reference

Just on grounding, given I'll be mounting all this on wood until finished, what can I do about the IEC ground and r-core ground?

[RichLund]

rhinomite -

Just leave the earth wire unattached. This is what I have done and it works fine. Mine is also on a wood base for now.

Use a 500mA 250V fast blow fuse.

[crazyfrog]

I'm waiting for my PCM1798 module. However, since This DAC has a low output (4 mA), maybe step up transformers could be a good choice? I checked the Lundahl LL1678 LL1681, LL1931, LL9206 and LL9226. Possibly something else?
Thanks

[shuggi67]

Hi I finally got of my **** and put together the DAC using the UTC-20, I got it all working and just switched it on and after some small issues got it all working.
However there is a buzzing sound that can be heard when listening with any decent listening volume levels, anybody got any ideas.
I,m using I a 1k resister on each leg of primary and the secondary I,m using a 680 ohm, so I'm basically using the same setup as the Tamura Trans Connection without the ground.

[xTr3Me]

you have no grounding connected?

[shuggi67]

Originally Posted by xTr3Me

you have no grounding connected?

I have ground for the power only, but I thought both the DAC and transformer are differential devices so grounds not needed ?.

[xTr3Me]

well theres no ground between transformer and dac board required but i thought u have no ground on the rca connectors?
maybe i missunderstand you.