Balanced vs Unbalanced (XLR vs RCA)

QuestionsCategory: QuestionsBalanced vs Unbalanced (XLR vs RCA)
El Hefe asked 6 months 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?

Virtual Private Servers replied 2 weeks ago

Doing our initial intro playing around with the Audiolines we experienced heaps of hiss when we plug in our ukes, but nothing using xlr leads from the mics.

WL Low replied 5 months ago

Having said all of the above, I still choose an XLR connection with fully balanced system anytime over RCA connection in single ended systems if given a choice. I feel it gives me a better starting point to build my system up. However, going for fully balanced systems tends to be a very expensive affair, due to doubling of component count inside the equipment.

That’s why most truly balanced equipment tend to be very expensive, but not all expensive equipment is designed and built fully balanced!

WL Low replied 5 months ago

While there is a distinct technical advantage in the use of full XLR system, in the domestic hifi application, it’s hard to justify that the better technical specifications automatically means better sound!

Also in domestic hifi equipment, it’s hard to say which equipment is of fully balanced design, unless one is very familiar with the designer’s hifi philosophy. So unless you have a full balanced(circuitry wise) system connected with full XLR cables, the arguments for XLR connection is hard to quantify, as the full benefits of XLR can only be harnessed if a system is fully balanced from source to amp, without exception. Even then despite the technical superiority of lower noise floor, higher signal level, again still would not automatically translate to good sound. It may be the more technically correct sound, but is it the sound that you, as the listener will enjoy?

3 Answers
lam seng fatt answered 6 months 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 6 months 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.

El Hefe replied 6 months ago

What is a four deck volume control?

lam seng fatt answered 6 months ago

Volume controls range from one deck for a mono amplifier and several decks for multi-channel AV amplifiers,
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