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FS: DAC output transformers - Onectics

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#21
Wiring diagrams

Hi Guys - good to hear that you got the transformers OK.

Below you will find the schematic, the pinout and a photo.
Basically all you need to know is that the input and output (+) sides are in opposite corners.
Pin 1 is a little closer to pin 2 than the others. That's the key.

You connect the output of your voltage DAC chip directly to pins 1&5 (input) and your cable or connector going to the amp/preamp to pins 5&8 (output). The output can be balanced or unbalanced, however you like.

Depending on you system, you may have to connect the (-) output pin to DAC ground to kill hum. If yo don't have to, that's great, but some systems want the DAC and amp grounds connected.

That's it, simple!
 

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#22
thanks muchly michael, was impossible to find any sort of datasheet and the last pics werent that revealing and only showed one set of 4 pins. so you use them as part of a sort of interconnect yeah? cut out the middle men so to speak. if I didnt have more than one target in mind I think thats what I would do too, either that or install them at the input of the amp and wire direct outs from the dac
 
#25
Hi Francesco - I have not used these transformers with the TDA1549, but they should work just fine if there is no DC on the outputs of the chip. Looking at the datasheet, there does not seem to be.

So in that case you would connect the TDA1549 left output (pin 4) to the + pin of the transformer (pin 1) and the ground to transformer pin 4.
Same for the right channel, pin 7 of the DAC goes to pin 1 of the transfo.

Cost for 2 to Italy is $98.88 US.
 
#26
Just a few notes on what the transformer does.

  1. It blocks DC that rides on the outputs of voltage DACs. This DC needs to be blocked from getting to the next stage. It can be done with a cap, but I find that transformers sound better. (in blind A/B tests)
  2. It acts as a low pass filter. Noise that is far out of the audio band does not get thru the transformer.
  3. Because of the above the subjective sound of the transformer tends to be more "analog" than most digital sources.

In measurements I've found that the transformer output has much less distortion , especially odd order distortion, in the top end than typical opamp output stages. It sounds smoother. There is also a nice sense of decay after the notes. Soundstage seems larger.

But mostly they are just a pleasure to listen to. And so easy to use. Pop in a pair, sit back and enjoy the music. =)
 
#27
mine arrived today, as described. I have not hooked them up to anything yet, but will update when I do. the actual target for these wont be ready for a little while, but I will try them on a couple other dacs in the meantime to get a feel for them and any tweaks that might improve matters further. one thing though...less distortion? seems to be contrary to every single bit of info I have including spec sheets for high quality transformers. if there is one thing one thing quality opamp stages well implemented with proper decoupling do well, its low distortion, sounding subjectively better of course is another thing entirely and from all reports (well maybe not all) they've got that in spades.

thanks again Michael
 
#28
Glad you got them!

As far as distortion, yes, transformers have more distortion harmonic in the low end than opamps. But my measurements show they have much less in the top end. So they sound different.

The subjective results have been near universal. They sound better. Quite why that is, I'm not sure, but most folks prefer them over opamp outputs.
 
#29
yep, its just one of those things we may never actually have the science to back up. which is actually kinda cool if you are willing to accept it rather than letting the numbers dictate your enjoyment. thanks again
 
#31
Hi Pano,

I bought the new nuforce uDAC... it is said to have the Sabre DAC with the analog Vout. The DAC sound is only so-so.. although, I've not had it for long.

Will the trafos work with this DAC?

Thanks.
 
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