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Balanced connections

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layercake1 View Drop Down
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    Posted: 17 Mar 2021 at 9:06pm
I’ve always found best performance with my home audio system when using balanced connectors. 
I see that even on some portable “dongle DACs “ balanced connections are being offered so just wondering why GSP are still staying with single ended RCA connectors given that these products are at the high end of performance ?
The output voltage seems somewhat higher on portable headphone amps that I have looked at and with high impedance headphones ‘‘this has to be a big plus. 
I’m not sure how important that is with an amp for home use. 
Interested to hear your comments 
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Ash View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 2021 at 9:42pm
I guess it depends on the susceptibility to interference for the particular scenario. Short cable runs may not benefit from balanced connections. With balanced connections, you have three signal options to compare. Standard phase (single-ended/unbalanced), inverted phase (so-called R3) or balanced (both phases). Between DAC and amps, I use inverted phase Lautus 1.5m instead of balanced Libran 1.5m as the benefit of sheath ferrites probably outweighs the benefit of having both phases. Perhaps an ultra-short Libran might beat the 1.5m Lautus though, just because shorter is better?
Lautus S/PDIF>Majestic>Lautus-R3>2xProprius>MySphere 3.1
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Post Options Post Options   Thanks (0) Thanks(0)   Quote layercake1 Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 2021 at 10:13pm
hi Ash,
I know balanced connectors ( and mains Supply ) came about through long cable runs in studios but I use 0.5 and 1m length XLR cables between pre and power amps and also from CD player to pre amp. Always sound better than RCA. Most high end gear seems to at least offer XLR in addition to RCA if not exclusively XLR. It probably costs more to design a fully balanced circuit so that’s a reason to exclude it on budget gear. 



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 2021 at 10:32pm
Originally posted by layercake1 layercake1 wrote:

It probably costs more to design a fully balanced circuit so that’s a reason to exclude it on budget gear. 



What are you insinuating?
Not simple enough for Google-Bot to understand...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lfc jon Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 2021 at 10:37pm
I was told shorter is better if using RCAs, but XLR was better over long distances, that was said to me as a general rule 
Pro-j tt,Ortofon 2m Bronze cart,Audiolab 8300CD,GS Reflex M. Solo headphone amp both with PSU1,MF M2si amp, Monitor audio silver 100 speakers, Atlas cables and Lautus cables
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 17 Mar 2021 at 10:39pm

To be honest, my patience at my time of life is wearing rather thin. Especially after serving as senior engineer designing all-balanced professional broadcast mixing desks (the above being a stereo desk based on my BBC journalist workstation desk). Do I have to constantly fend off the bullsh*t brigade?





Edited by Graham Slee - 17 Mar 2021 at 10:49pm
Not simple enough for Google-Bot to understand...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 18 Mar 2021 at 12:08am
Balanced is the feeding of phase and anti-phase signals down a twisted pair, from a 600-ohm source to a 600-ohm receiver (150 ohms using a transformer).

Show me any modern hi-fi gear capable of sending at 600 ohms? OK then, I'll name one - the Majestic.

600 ohms is suitable for the telephone system and theatre snakes, whilst high-quality transmitter feeds will be 150 ohms via transformers. That is how program leaves a studio, connected to underground "BT lines," and emerging at a transmitter site some one to two miles away. Feeds to repeaters (AM and FM) might then be by microwave.

Interesting fact: The Viking AM "Euro transmitter" is on the other side of the Humber estuary, so either the BT line goes the long way round or goes by an underwater cable. The transmitter site remains; although the station closed, it could be picked up anywhere in western Europe. The feed was line level.

To obtain the required balance for noise cancellation, required a gain tweak in the non-inverting opamp input attenuator. The minimum signal gain is 2, although "noise gain" is unity. The reason for using opamps is their gain accuracy. The balance tweak was set on-test using an audio analyser measuring precision mixing resistors, such that the signal was reduced to an absolute minimum, below the noise floor.

The arrangement used was designed by BBC engineer David Birt. Virtually all high quality feeds used NE5534 opamps.

An improvement on Mr Birt's design is the all-inverting version because of it having no common-mode distortion. The conventional feed uses inverting and non-inverting stages for the phase and anti-phase signals. The non-inverting stage suffers common-mode distortion, which is compounded by the same occurrence in the receiving circuit.

In most studios, balanced was mandatory only because it was used everywhere else in the station, and it is cost-effective to stock XLR's and TRS jacks rather than a mix and match of connectors.

Some might think the XLR is used exclusively, but they'd be wrong. TRS features extensively in rack rooms for signal routing via jackfields. These tend to use the old-style PO jacks and sockets (the Majestic accepts both). My colleague, John C, has many years of experience wiring them into racks.

The reason for using balanced is NOT to avoid grounding problems (although the bullsh*t hi-fi mantra goes like that).

To say that balanced sounds better than a single-sided coax over a few metres is, in my experience, highly biased. It is marketing hype, and that is why I have so little patience when, after years of talking about balanced audio, another starts yet another topic about it.

As I've said, please show me some balanced hi-fi unit which complies with impedance matching. Show me some hi-fi unit where the balance has been tweaked on a precision test to be actually balanced, and not just for boast!
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