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-   -   THE TRUE BALANCED SOURCE (http://www.diyaudio.com/forums/digital-source/207602-true-balanced-source.html)

Stee 26th February 2012 05:25 PM

THE TRUE BALANCED SOURCE
 
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To get a clean sound you must have a source DAC with XLR balanced outputs
But we must know that the drives are not complementary P and N

they are composed of the same identical semiconductors
but driven by a PCM digital number in opposite phase.

So to cancel the print tone of the Digital to Analog converter
must operate a subtraction
NOT A SUM

this is possible by using a potentiometer for the adjustment of the listening volume in series with a resistor of equal value

suggest 1K :smash:

Speedskater 27th February 2012 09:49 AM

Pin #1 of a XLR balanced analog circuit is not ground, it is not part of the audio circuit. XLR pin # 1 is the shield and should only be connected to the chassis near the connector.

Stee 27th February 2012 10:33 AM

NATURAL MODULATION
 
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that PCM CONVERTER is born with wrong way
IS NOT MADE FOR AUDIO
we must know that the drives are not complementary P and N
as Law of twice denied would.

:):):)

this means that the method of complementary
must be applied in a manner opposite
To qualify for compensatory timbre of the two systems

SoNic_real_one 27th February 2012 10:39 AM

You are wrong. DAC cips are build in CMOS technology - complementary-symmetry metal–oxide–semiconductor.

And anyway, that theory canceling with P and N applies only for amplifiers final stage working in AB class. Nothing to do with DAC output that is a class D type (because of the Pulse-Modulating signal that reperesents). The digital signal is... digital, there is no "ballanced" PCM or DSD.

Read a book, something...

Stee 28th February 2012 11:35 AM

TEAC UD-H01 convertitore D/A con USB
The current of the PCM1796 on each of the output pins (IOUTL+, IOUTL–, IOUTR+, IOUTR–) is 4 mA p-p at 0 dB (full
Scale). Differential Current Output: 4 mA DON'T MEANS COMPLEMENTARY OUTPUT
http://www.ti.com/lit/ds/sles100a/sles100a.pdf

qusp 28th February 2012 12:02 PM

hmm yes that old pin 1 chestnut, dont tell me you missed it?

Stee 28th February 2012 07:30 PM

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To find out if I'm right or wrong, just do a simple test -

a double potentiometer connected to the balanced outputs, stay around the middle of the range, the more you are close to zero is the most effective cancellation -

then turn up the gain of the amplifier with inputs unbalanced RCA :spin:

try to hear what happens to the sound:
a magical horizon suspended in midair generates sounds :eek:

qusp 29th February 2012 02:44 AM

no need for experiments, its pretty basic electronics that pin 1 is for shield/chassis not signal ground. if you need to connect an RCA output/input to a balanced input/output, use an instrumentation amp or transformer, which ever is suitable, dont try and make a magic cable do it

Stee 29th February 2012 10:08 AM

http://www.esafono.it/horizonevents.pdf


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