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Author Topic: Making a balanced impedance adapter for HD800 (4pin XLR)  (Read 654 times)

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wnmnkh

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Making a balanced impedance adapter for HD800 (4pin XLR)
« on: October 08, 2014, 05:45:27 PM »
I am rather confused with balanced configuration. For unbalanced, I could just put a resistor of desired resistance on signal path.


L/R --> Resistor --> headphones
G <-----------------

But I am a bit confused with balanced wiring. So what I see is L+, L- for left channel, and R+ & R- for right channel.

If I want to increase the impedance to 43 ohms (magic number from HDVD800), should I just put a 43ohm resistor on both L+ and R+ wires?
or do I have to put the resistors on all four (L+, L-, R+, R-) wires? if that's the case, should the value of the resistor 21.5ohm instead of 43ohm?
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Solderdude

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Re: Making a balanced impedance adapter for HD800 (4pin XLR)
« Reply #1 on: October 08, 2014, 07:48:41 PM »
Use a 22 Ohm resistor in series with each wire.
You will end up with a 44 Ohm resistor in balanced mode (as if the amp has a 44 Ohm resistance)

It is really the same as 43 Ohm so good enough.
Should you REALLY want the magic 43 Ohm than you would have to mount a 1k Ohm resistor in parallel to each 22 Ohm resistor.
You would end up with 43.05 Ohm (not counting tolerances nor wiring)

Or use a single 43 Ohm resistor in series with L+ and one in series with R+ and the L- and R- must be connected without a resistor.

From the 'all balanced' POV 4 resistors is closer to the 'ideal' in a technical sense it doesn't matter at all
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wnmnkh

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Re: Making a balanced impedance adapter for HD800 (4pin XLR)
« Reply #2 on: October 09, 2014, 02:31:42 PM »
Thank you. I guess I will use a single 44 adapter for each positive wire (R+, L+)
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