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OLD THREAD DAC End by Andrea Ciuffoli

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#843
Ekkeri said:
Does anyone have a pic from a genuine AD1865N-K? From Digikey for example, not those old ones..
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DAC from Digikey:
 

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#844
Finally the DAC End 2 are playing in my house, I am very happy of the result!

All the pcb board are ok (see previous notes).

Actually I am using 0.22uF Jensen Copper film paper in oil on output and I have changed the 2 output resistors to 1Mohm to have a 500K to ground.

Using a 100K DACT stepper attenuator I have -1dB at 20Hz.

I will add another 0.22uF in parallel to get a better frequency response.
 
#848
adamus said:
An externally hosted image should be here but it was not working when we last tested it.


pic of the guts.

yes some of the components are the wrong size, its what i had in the parts bin and i got creative.
Click to expand...

It is very nice, work well, but i dont like all suppy DAC and supply IV stage use on transformer!

You try one for DAC, one for I/V stage, the soud is better

You tested the soud of DAC?? what do you thing?
 
#858
quanghao said:
You dont use R8, R9, you conect direct is ok. No noise for filament.
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I did try that. Its a fine balance between too hot resistors and too hot regulator.

With no resistors the regulator was extremely hot, so come volts needed to be dropped. with r8 and r9. 1ohm in parallel worked well. P=I^2 R, P= 1.28watts... s still reasonably hot, but only 0.65 watts per resistor so the 3w rating is fine for the 1 ohm in parallel.

As for the single transformer. I agree that technically seperates are better.... but the salas shunts are so effective that I predict that in no way could you here the difference, on the scope they sit stable and flat with very very little noise. cheers salas (oh... and they look pretty too!).

The sound is different to my old transformer coupled dac. Its not broken in yet, but at the moment is warmer, with more fluid top end.

It also acts a space heater! As a caution to other builders, you must have vents in the top panel, the regulators and of course the tubes put out considerable heat. these 5687's are hot little beasts.

If i get bored listening today, i will have a play with the filter. I currently have the 2ks in place and the 120uh bourns inductor. I may go chopping.....

IF people cant get the caddocks, then i can thoroughly recommend texas components. Very nice company to deal with and with reasonable prices (much cheaper than the uk... one charcroft resistor in the uk is near enough £20, i got both texas resistors for less than that)
 
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