Balanced often had a grounded center-tap.
You seem to want a "floating" link. These exist but can have problems with strays.
In modern gear, "balanced" is nearly undefined. Almost all have flaws in some connection.
Notably the notion of an X2 error in some connections.
1V on red and -1V on blue is clearly 2V... why not? Who listens to ground?
If there is a reference/connection to ground, and there is ground noise between sender and receiver, you're f*cked.
This is one of the very few cases where you can fix a problem by NOT making a connection!
And yes, equipment often shows incompetent design, like XLR pin 1 connected to signal ground! Yes it still happens!
Jan
This is one of the very few cases where you can fix a problem by NOT making a connection!
And yes, equipment often shows incompetent design, like XLR pin 1 connected to signal ground! Yes it still happens!
Jan
I admire efforts to reduce the comprehensive difficulty of the less fortunate... using a single asterisk helps...
There seems a growing trend in using balanced XLR connectors in DAC's like Topping, SMSL, etc. Some have incredible specifications, being recognized in places like TAS (The Absolute Sound). I recently purchased one, the SMSL su-9n reviewed by Audiosciencereview.
https://www.audiosciencereview.com/.../smsl-su-9n-review-balanced-stereo-dac.27300/
Notwithstanding that minimalistic jitter, harmonic and intermodulation distortions may not be the totality of all relevant artifacts supporting a positive psycho-acoustic experience these ultra-low values can lead to a better understanding in the mechanisms involved that supports those experiences.
Not if there is only one ground connection, and all is properly shielded.
This comes from classic (1890s-1950s) American telephone/broadcast practice, but is probably the same in UK and the continent.
Sorry this was accidentally sent without being complete... although the following may not help either.
There seems a growing trend in using balanced XLR connectors in DAC's like Topping, SMSL, etc. Some have extraordinary specifications, being recognized even in places like TAS (The Absolute Sound). I recently purchased one, the SMSL su-9n reviewed by Audiosciencereview.
https://www.audiosciencereview.com/.../smsl-su-9n-review-balanced-stereo-dac.27300/
Although ultra low harmonic, intermodulation and jitter distortions may not support the most positive psycho-acoustic experiences in comparison to alternative devices that could have more obscurity and/or distortion (2nd and 3rd harmonics for example), they can provide some understanding of the nature of the mechanisms involved. To support such study, for devices like the SMSL the XLR connections may seem redundant given that using the alternative RCA output connectors the 2nd harmonic is still about 140dB down, or 1 part in 10 million. However, if these levels of distortion are considered important to maintain in a wired connection to some unknown amplifiers, a balanced XLR connection would seem imperative given that extraneous artifacts could overwhelm that 1 part in 10 million if alternative RCA's where used in place.
The conclusion is that testing of devices by audiosciencereview and others is done to test performance under ideal conditions, those that inhibit extraneous noise being introduced in connection cables, etc., to their test equipment. Hence it seems important to consider the nature of external sources that could influence either RCA or XLR connections to whatever target device is being used. Under circumstances the intent is to achieve or maintain the levels of distortion capable of devices like the SMSL the XLR connections offer the least risk to contamination if the target device has such a feature. Basically, in todays realm of ever decreasing distortion XLR's, or their equivalent balancing, are likely to become standard.
Voltages are "balanced" in the equity of two opposing voltage in relation to some reference voltage, hence "imbalance" is the condition of inequity of voltages to that reference. This to suggest that in the determination of a state of balance/imbalance requires a third voltage as a reference in the comparison. From this perspective the two coils in a moving cartridge are each "floating" as a pair of independant two terminal voltage sources. Two terminal coils are not balanced if the only reference is the opposing terminal, since under those circumstances there is no condition of imbalance. This is likewise true of a two terminal battery floating in free space.
The degree of non-symmetry is normally considered in relation to the degree of balance or imbalance. It seems that you might be equating "balanced" as meaning "floating" of a two terminal input source, whereupon one terminal is ultimately connected as referenced to ground on the input of some device. So the simple answer seems 1 Vrms ground referenced or 2 Vrms differential (meaning across the terminals). The degree of amplification/attenuation required is a function of how the signals are handled by the device that the signals are connected.
One more time.
A balanced line is a line that has equal impedance, at the source, at the receiver and the cable itself. A balanced line doesn't say anything about the voltage levels and the reference for those levels. Imbalance has nothing to do with voltage levels but is about imbalance in impedance. There's a very good explanation at Wikipedia.The purpose of a balanced line is to make sure that any impressed noise or RF junk is equal in both lines so it is cancelled at the receiver.
A symmetrical line is a line that has equal but opposite phase signal levels against some reference. The purpose of a symmetrical line is to maximize dynamic range.
Combinations are possible.
Jan
A balanced line is a line that has equal impedance, at the source, at the receiver and the cable itself. A balanced line doesn't say anything about the voltage levels and the reference for those levels. Imbalance has nothing to do with voltage levels but is about imbalance in impedance. There's a very good explanation at Wikipedia.The purpose of a balanced line is to make sure that any impressed noise or RF junk is equal in both lines so it is cancelled at the receiver.
A symmetrical line is a line that has equal but opposite phase signal levels against some reference. The purpose of a symmetrical line is to maximize dynamic range.
Combinations are possible.
Jan
OR to minimize crosstalk by cancelling transmission.
You can't make-up these definitions without a complete framework.
You can only cancel xtalk if you have an impedance balanced line. That's the whole point. Make sure that the xtalk signals are impressed on each line at identical levels, THEN they will cancel at the receiver. If the xtalk in the two lines is not identical, it will not cancel.
Jan
Jan
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Sure. From: https://en.wikipedia.org/wiki/Balanced_line
"In telecommunications and professional audio, a balanced line or balanced signal pair is a circuit consisting of two conductors of the same type, each of which have equal impedances along their lengths and equal impedances to ground and to other circuits."
"Balanced signal pair" suggests of "signal" as related to voltage and/or current. A "signal" in electronics "refers to any time-varying voltage, current, or electromagnetic wave that carries information". Hence a "balanced signal" with the qualifier that it must be of "equal impedance" requires that the "signal" consists of a constant ratio-metric proportionality of voltage to current in the line. As you suggest it doesn't say anything about the voltage levels, rather it does about the voltage to current ratios that must be satisfied to meet the criteria of constant impedance.
"Lines carrying symmetric signals (those with equal amplitudes but opposite polarities on each leg) are often incorrectly referred to as "balanced", but this is actually differential signaling. Balanced lines and differential signaling are often used together, but they are not the same thing. Differential signaling does not make a line balanced, nor does noise rejection in balanced cables require differential signaling.
Hence I was clearly in error using the term "balanced signals" in lieu of using "symmetric differential signals" as intended. These are the kind of errors that I often make given my preponderance not to convey information in an understandable fashion. Back to your question in your post #19 it seems the simple answer is 1Vrms single ended or 2Vrms differential. It is considered that the inclusion of "differential" is only used if a ground isn't a voltage reference point, although it could be. As suggested above, signals are not required to be "symmetric differential" hence the 1Vrms line could also be called 1Vrms differential under the special circumstance that the other voltage of comparison is at or near ground potential.
Agreed, yes, clear.
My question came from the need to convert a balanced signal to single ended.
Some circuits include a -6dB gain, apparently to keep the level the same. There are also audio amplifiers with both single ended and balanced inputs, quoting a "6dB higher sensitivity when using the balanced input".
Jan
My question came from the need to convert a balanced signal to single ended.
Some circuits include a -6dB gain, apparently to keep the level the same. There are also audio amplifiers with both single ended and balanced inputs, quoting a "6dB higher sensitivity when using the balanced input".
Jan
Going back to post #1 it seems that I am not the only one confused by balanced vs. differential networks. The website referenced in post #1 shows a diagram of a differential input/output operational amplifier calling "Balanced". The input terminals are marked + and -. hardly suggestive of positive and negative impedance.
https://ifi-audio.com/products/zen-phono/
https://ifi-audio.com/products/zen-phono/
Interestingly the following is excerpted from the Project website describing "Fully balanced"
https://www.project-audio.com/en/product/phono-box-rs2/
Fully Balanced
The Phono Box RS2 employs a true fully balanced design principle. Balanced transmissions consist of a hot and a cold (also called + and -) signal. Both the + and – signal chains effectively carry the same musical information. A true balanced amplifier can now extract the final musical information out the +/- signals and subtract, remove, all noise that could potentially be added along the transmission. In a true, fully balanced amplifier, like the Phono Box RS2, the + and – sections of both the left and right channel are treated individually, which doubles the amplifier sections by 2 as a result.
https://www.project-audio.com/en/product/phono-box-rs2/
Fully Balanced
The Phono Box RS2 employs a true fully balanced design principle. Balanced transmissions consist of a hot and a cold (also called + and -) signal. Both the + and – signal chains effectively carry the same musical information. A true balanced amplifier can now extract the final musical information out the +/- signals and subtract, remove, all noise that could potentially be added along the transmission. In a true, fully balanced amplifier, like the Phono Box RS2, the + and – sections of both the left and right channel are treated individually, which doubles the amplifier sections by 2 as a result.
Commercial 'I want you to buy this' literature should not be blamed or considered as a source of correct technical info. 😎
Jan
Jan
What they appear to miss is that this only works when "all noise that could potentially be added along the transmission" is added in exact the same level in the two chains and that the subtracrtion stage has high common mode supression. As I said, commercial "I want you to buy my stuff" is just that.
Jan