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Old 3rd January 2010, 09:24 AM   #131
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Patrick,
which are the questions ?
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Old 3rd January 2010, 09:31 AM   #132
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Whether you need 2x AD1865 for balanced output and what the circuit would then look like ....
I thought this is best answered by someone who has actually developed the original circuit.


Happy New Year and thanks for sharing with us, Andrea,
Patrick
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Old 3rd January 2010, 10:00 AM   #133
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Yes, it is possibile get a balanced output using 2 x AD1865 but I don't think this will give a best sonic performances.

A balanced output mean the necessity to add a differential output stage so it will increase the complexity and the cost.

A balanced stage can eliminate some distortion and power supply noise but here we have, in any case, a very low distortion stages and a good power supply.
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Old 3rd January 2010, 10:55 AM   #134
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Here the final output stage

THD measurement with and without 10Kohm load.

Output impedance less than 1Kohm

Power supply voltage about 270V

Ik = 2 x 8mA

Freq = 10Hz at -0.7db

Vout = 2Vrms with an input of 154mVrms

THD = 0.3% thd max on 10Kohm load
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Old 3rd January 2010, 10:59 AM   #135
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Here others attach

To prevent dc voltage on output durung switch-on and switch off phase a relay will short the output to the ground for some seconds.

The delay circuit is the same used in the my design of Monrio Top-Loader CD Player (value 10000$).
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Old 3rd January 2010, 11:16 AM   #136
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Someone else was happy with a direct transformer (Sowter 9545) output on the AD1865.
That way you can get balanced output for nothing extra.

AK4396: best solution for output stage

Any comments, Andrea ?


Patrick
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Old 3rd January 2010, 12:49 PM   #137
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I have Sowters in my CDP done by Modwright, back when I was more afraid of digital mods. I dont have the schematic, but the unit sounds wonderful. The IRON anyway, cannot be that bad. It does not use any tubes.
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Old 3rd January 2010, 04:12 PM   #138
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Patrick see the my answer in the other forum
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Old 3rd January 2010, 04:23 PM   #139
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I did.

Patrick
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Old 4th January 2010, 04:18 PM   #140
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hi quanghao, befor order the full set PCB i'd like to know something about the DAC.
i hope you would forgive my bad english and mine deep ignorance.
then: which type of transformer i need to complete the power supply and the rest of the DAC?
where i can find the AD1865?
ebay?
there are a lot of fake on ebay(opamp, capacitors, etc etc)!
thanks and sorry everybody for my stupid question.
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