Balanced vs Unbalanced (XLR vs RCA)

QuestionsCategory: QuestionsBalanced vs Unbalanced (XLR vs RCA)
El Hefe asked 2 years ago

Hello,
Comparing between a properly implemented balanced circuitry and unbalanced circuitry, which one would you choose and why?
There are a lot of hifi enthusiasts claim that there is actually no different in sound and XLR is only used in pro audio for long distance cabling requirement as it reduces noise.
While the statement on long cabling is true, I dont think it is the main reason why balanced or XLR is implemented in hifi gears.
For me personally, first of all, XLR sounds louder. But not every time it sounds better than RCA.
Whats your thought?

3 Answers
lam seng fatt answered 2 years ago

There is a true balanced circuit and a pseudo balanced circuit. From what I understand, a true balanced circuit actually has two circuits – one in positive phase and the other in negative phase. The idea is to combine both and have the benefit of common mode rejection, which reduces noise. In a pseudo balanced component, the signal is balanced only at the input and output while the circuit inside the component is single-ended.
If the preamp and poweramp all have true balanced circuits, then it is better to connect them with XLR cables to reap the benefits of balanced circuits.
From http://ifi-audio.com/wp-content/uploads/data/PART1_iCAN%20PRO.pdf

Compared to a single-ended design with exactly the same circuit, True
Differential Balanced lowers noise by 3dB and also lowers THD dramatically. Additionally, it allows the signal level to be doubled, so True Differential Balanced circuitry also produces 9dB (or 3 times) greater dynamic range.
From my experience, true balanced circuits give a larger soundstage, more dynamic sound and less noise.

lam seng fatt answered 2 years ago

Apparently one of the best ways to determine if the component is true differential balanced is to check the volume control. If the volume control is four-deck, then it is a true differential balanced circuit.

lam seng fatt answered 2 years ago

Volume controls range from one deck for a mono amplifier and several decks for multi-channel AV amplifiers,
Please take a look at this range from http://www.dact.com/html/attenuators.html
 
Attenuator-family

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