I am vaguely aware of the scientific merits of "Balanced wiring". I am only interested in the "Audio" merits. CJ, a company that makes some of the best equipment on the planet, has no "Balanced" equipment that I know of. This puts some doubt on the audio merits of this circuitry. What is your opinion.
But during my test, I notice that it is not the case. I don’t know if its my system act differently or not.
The problem is that your gear doesn't support the balanced line standard, also known as AES48. This means that the interconnect cables will play a role in the system sound at the very least. It may well be that the balanced signal is going through additional circuits that the single-ended signal isn't.
To get everything out of balanced operation (otherwise, why do it?) you have to follow the standards. Otherwise the results are highly variable! Single ended connections don't have much in the way of standards. High end audio pretty much ignores AES48, perhaps because its harder to do. One of the most difficult issues is that in a balanced connection, the ground connection is ignored- there's no signal return currents in the shield of the interconnect cable. This is the aspect of balanced operation that is most commonly violated in high end audio.
I am also confused with the different between Balanced vs Unbalanced. When I google it, they all say XLR better than Unbalanced. But during my test, I notice that it is not the case. I don’t know if its my system act differently or not. Here is my gear. McIntosh C52 preamp Lumin D2 Streamer Cambridge DAC Magic 200M. https://www.moon-audio.com/silver-dragon-digital-cable-v1.html
Right now, I have the Digital Coax Silver Dragon silver cable connected from the Lumin D2 to my external DACMagic 200M. The DACMagic 200M has two output XLR or RCA. I have both cables connected to my McIntosh C52 Preamp line in. So when I play the music from my streamer, I can switch from RCA or XLR to compare different. I noticed the sound from the RCA is much clear and brighter. I played a few songs that I listen to million times and hear the hi-hat way more clear than the XLR. I just don’t know why. Other people who used the XLR saying it has more clarity then RCA. But I don’t hear that at all. Even though I had my girlfriend did a blind test. She always pick the RCA has crystal clear sound.
Does any one have that experience ?
If I am not using the external DAC. I have the Lumin D2 connected to the digital coaxial silver dragon and XLR to the McIntosh C52. Switching back and forth for comparison. The clarity still from the Digital Coaxial cable. Is it because the XLR is more flat and neutral sounding?
Ralph, I get what you are saying, and I may try it sometime, but I don't use a bypass cap. I have the filament current of my input tube going through the cathode resistor to establish bias. That R is only a few ohms so too low to do what you say.
Koegz, in a nutshell, that is the whole point of balanced line operation. The system was created to eliminate interconnect cable problems.
There is a standard that has to be conformed to in order for this to be true. If the conformance is not there, you will still hear differences in the cable.
The primary hanging point with most high end gear is the 600 ohm termination standard. What this means is that the equipment should be able to drive a load of 600 ohms (which might be at the input of the amplifier) without difficulty (for example loss of bass). For tubes this usually means an output transformer, or very large coupling caps, 100uf or more. Most high end manufacturers don't want to put in such a large capacitor at the output of the preamp, as it will color the sound and for the same reason aren't usually too keen about an output transformer either. That's why conformance to the standard is rare.
Atmasphere; one question. are you saying, in an xlr set up, that the interconnectors, as long as they are of reasonable quality, really do not matter? I have found this to be true. you seem to know a lot about this. I would value your opinion and any explination. not to technical please. thanks
OK Herman, yeah maybe a little, or maybe more than that :) But really, its pretty easy. If you drive the cathode of the input tube rather than the grid you have what is called a grounded-grid circuit. You need a coupling cap to do it. Turns out that the value of that cap is the same if that cap were to be used as a cathode bypass cap, in the case of normally driving the grid.
So, why not drive both the grid and the cathode in opposition? In practice, this works quite easily. You install an XLR on the amp, and attach the cathode bypass cap (if there is one, if not you have to supply one) to pin 3 of the XLR rather than ground. Pin 1 of the XLR goes to ground, and pin 2 goes to the RCA input. Now if you drive the grid only, single-ended, you will want to put a jumper between pin 1 and 3 if the cap was a bypass cap. If not, you don't need the jumper.
The only trick is that the grounded-grid input is pretty low impedance. You might want to have an auxiliary resistor that plugs into the RCA input that sets the normal input (pin 2) to the same value. This is not a problem if your preamp supports the balanced line standard.
I have this hookup running right now on a set of DIY amps I built, which are a set of push-pull amps using 45s for output tubes (class A), and a single-ended driver circuit similar to a Dyna ST-70, only all-triode. I didn't bother with the extra resistor, as this input behaves a lot like a differential input. I guarantee you that if you tie the two inputs together and try to inject a signal, you will find there is a substantial CMRR.
Herman, Yes, that's true. I've found in practice though that it does not seem to come up. Also, again the CCS circuit plays a huge role in this- even if there is a mismatch in the tubes, you don't seem to get any extra noise.
BTW, any tube amp with a single-ended input can be modified to have a true balanced input, often without any change to the way it operates with a single-ended input, and without using an input transformer. IOW its possible to have a balanced front end and an SET as well, with all the benefits.
Ralph, I agree with all of that. I wasn't very clear when I said
for everything to work as designed you have to have a circuit capable of producing 2 signals that are exactly the same except for their polarity.
I never meant to make any correlation between signal and CMRR. I should have said
to maximize CMRR the circuit must amplify any common mode signal to produce 2 noise signals that are exactly the same except for their polarity.
If one side amplifies the common mode signal i.e. noise more than the other then they don't completely cancel. That can't be corrected in the next stage. Sorry for the confusion.
Herman, look at it this way: a differential amplifier does not care if it is getting a single-ended or balanced input signal. It will act exactly the same in either case. So if the input signal has two opposing inputs that have slightly different amplitudes, the differential amplifier will still not care.
IOW, 1 volt at one input while the other is at ground is the same as two 0.5V at both inputs. Or 0.25V and one input and 0.75 at the other. The differential amp does not care- it just amplifies what is different between its two inputs, regardless of differing amplitudes.
In the meantime, the CMRR is not dependent on the signal, its dependent on the differential amplifier, and it gets an awful lot of that from how effective its Constant Current Source (CCS) is.
The bottom line is you can have an imbalance and it will work out fine, so you don't need loop feedback in the circuit to insure perfect balance.
BTW in general this issue is really poorly understood, so that was an excellent question!
Bob, I was talking about the output voltages having different amplitudes because they get amplified by different amounts. Isn't Whitlock saying that it will still reject noise even if the signals aren't balanced? I don't think that is the same as saying it will reject noise if the two inputs aren't amplified by the same amount.
I thought one requirement for a high CMRR was that an equal input was amplified by an equal amount so they cancel? How does that get corrected in the next stage?
That is no different from using multiple tubes or transistors in other amplifiers
I completely agree, and all of those would be better if they could avoid doing so.
Unlike an SET, they don't make nearly as much distortion at higher power,
Totally agree, that's why I use 107dB efficient horns and usually listen at moderate levels. If I crank it up I'm not too worried about distortion as long as it isn't gross.
BTW I have heard your amps at the Analog Room in San Jose hooked up to a pair of Avalons and it sounded very, very good. Too bad the proprietor is so condescending and the place reeks of cigar smoke. I readily admit it looks like you have turned the OTL from a fireworks display into a fine sounding piece of equipment.
Rleff, it really depends on the speaker rather than the technology. Its the 'all else being equal' part that prevents an answer beyond that. Either one can be awesome or suck really bad.
Ralph which would you prefer your electronics with a electrostatic or a horn system with all else being equal;I am just curious.I am a soundlab owner and have been watching the horn thread that has been going on with great interest as I am not familiar with that technology.
Herman, just for the record, I like SETs a lot myself and have built a number of type 45 and 2A3 based amps.
But before we go into that,
One unmentioned difficulty is that for everything to work as designed you have to have a circuit capable of producing 2 signals that are exactly the same except for their polarity. I agree that using a differential circuit makes it easier but there are still a lot of things that can cause an imbalance. If there were not the CMRRs achieved would be much higher than they are.
The above comment is not exactly correct. It only applies to the use of balanced circuits **that are not differential**. IOW, if you have an imbalance in a differential circuit, it will be corrected in the next stage. In addition, a differential circuit will absolutely insure that the inverted and non-inverted phases of the signal will be absolutely 180 degrees out of phase but otherwise identical, even if their amplitudes are slightly different. So it does not have to be as exact as you describe in order for the CMRR to be retained.
I have found in the execution of differential circuits that the constant current source used in the circuit is a big deal. Most CCS circuits only have a single device (tube or transistor) and so are ineffective. They have to have at least 2 stages to work right. My point here is that doing balanced right is like anything else: a matter of execution. We get CMRRs well in excess of 100 db, even without perfectly matching signals.
Although its a different subject, you did mention the multiple tube issue in OTLs. That is no different from using multiple tubes or transistors in other amplifiers, and just like in other amps (including SETs) there are ways to make those tubes work quite well together! I agree that SETs have a lot of linearity, especially in that first watt where everything is so critical. It might interest you to know that the only other type of tube circuit that has the same behavior is an OTL- if designed right they have no crossover or notch issues, so like an SET the distortion vanishes as power goes down. Unlike an SET, they don't make nearly as much distortion at higher power, and so offer less coloration and smoother sound. It is easy to demonstrate. PM me.
Good source + triodes + good horn speakers = bliss
This is a formula that has worked well for me for a very long time :) I add to it: balanced operation- this ends the sonic role that interconnects traditionally play.
Sidssp, There are many forms of distortion. SETs are the most linear devices on the planet. How does that equate to distortion generator? I lived through the distortion wars of the 80's where we ended up with vanishingly low distortion on amplifiers that would make your ears bleed.
The problem with SET amps, low power. The solution, highly efficient speakers.
Good source + triodes + good horn speakers = bliss
Sitting with a smile on your face and your toes tapping or dancing around the room are the defining factors. Audiophile nerds who sit frozen in one spot, never moving, never physically reacting to the music, discussing how black the background is and how much air there is around the instruments have so completely missed the point that they are hopeless. I hope you aren't one of these nerds.
06-01-10: Sidssp IMHO, SETs are distortion generators. They can make a Yamaha violin sounds like a Stradivarius.
So can poorly designed/executed push-pull circuits(tube & solid state). Well designed/executed SE circuits in properly associated systems can also make Stradivarius sound like Stradivarius. The same can be said for most other well designed/executed circuit topologies.
Herman, IMHO, SETs are distortion generators. They can make a Yamaha violin sounds like a Stradivarius. Like guitar amps, they should be considered more like a musical instrument than audio reproducing equipment. Can SETs sound good? Sure, I like them too. I used to built them when I was much younger. But they are not Hi-Fi amps.
I know many people will disagree. Since we are talking about Hi-Fi here, Hi- Fi or High Fidelity means faithfully reproduce. If an amp can make a Yamaha violin sounds like a Stradivarius, it is not Hi-Fi, no matter how good it may sound to some people.
I would like to point out that it's not all lollipops and roses. One unmentioned difficulty is that for everything to work as designed you have to have a circuit capable of producing 2 signals that are exactly the same except for their polarity. I agree that using a differential circuit makes it easier but there are still a lot of things that can cause an imbalance. If there were not the CMRRs achieved would be much higher than they are.
The other problem I see with Atmasphere amps is the OTL output. Ralph has done an admirable job of overcoming the stability problems experienced by earlier designs but I don't think you can overcome the inherent problems caused by paralleling a bunch of tubes and using them in a push-pull circuit. I have no explanation but cathode follower amps have never sounded as good to me as common cathode.
I have 3 directly coupled triodes and an output transformer between my source and my speakers which I believe leads to much better sound than you can achieve with a more complex circuit. Of course, if anybody wants to send me an OTL amp to try I would be happy to entertain them.
While I do agree with Ralph's explanation of the technical side of things I disagree that this leads to circuits that sound better than an SET, but of course this is a debate that cannot be won on either side.
Ralph, thanks for the excellent comments and explanations. FWIW, I am in complete agreement.
I would just add the thought that in principle it is certainly possible to use active devices, as alternatives to the transformers you mentioned, to fully achieve the benefits of balanced interfaces with designs that are not balanced internally. However, as you indicated most examples of that approach are not in compliance with the 600 ohm standard and/or are poorly implemented.
I did forget something- a request. There are those of you here that disagree with my prior post and will have talking points. Please keep them if you can to one talking point at a time, so that we can be clear that they get responded to in a coherent fashion. Thanks!
Alright, there is a fair amount of misinformation in this thread, and I thought since we essentially introduced balanced line operation to high end audio, I thought I should correct the misinformation herein and explain some of the whys.
Balanced operation exists for the sole reason of reducing/eliminating artifact in the interconnect cable. It will do so regardless of how long or short(!) the cable is. If it is set up right, it will always outperform single ended cables.
Balanced operation does not require twice as many components!! That is a very common myth. This is true even if the the preamp or amp is fully balanced. Now some balanced cirsuits will require twice as many components, and you will find that they also do not perform as well. The best balanced circuitry will also be differential. Differential circuits do not double components.
You can also run balanced operation without balanced components and realize all the benefits of the cables. This done via the use of transformers, as any transformer can convert from balanced to single-ended or vice versa, simply due to how its hooked up. I don't like transformers myself, but in cases where its either long interconnects or long speaker cables, the transformers and long interconnects will win out easily.
When I said that balanced operation is devised to eliminate cable artifact, I meant it- the cost of the cable becomes unimportant. However, to accomplish this, the balanced system has to be **low Impedance** (600 ohms is the standard, IOW what is driving the cable should be able to drive 600 ohms without distortion or loss of low frequencies). It is this last bit that has 90% of high end audio products falling flat on their collective faces, and is the reason why there is controversy about balanced at all. IOW if you don't embrace the standard, your balanced setup will be no better than single-ended and possibly worse.
Now if the components involved are internally balanced, you will realize two benefits: lower noise per stage of gain, and distortion cancellation with each stage of gain. So balanced preamps and amps can take advantage of that by using less gain stages as a result. This means that they will be more transparent, as reducing distortion reveals detail. I can expound more on that if you like.
Phono cartridges are balanced sources so LP can be run from needle to speaker fully balanced. The same is true of microphones and tape heads. CDs may or may not be balanced, but there is still advantage to using balanced operation with them due to the advantages of the interconnect itself. This is **not** to say that if your CDP is single ended that you can just stick a balanced cable on it and it will get better, it means that if you use it with a balanced preamp, the preamp will handle the signal fine and it will be delivered in better condition to the power amp.
I am certain I have forgotten a number of points but I expect they will come out in the responses to this post. The bottom line though is that balanced operation is a pathway to greater resolution and lower noise than is possible with single ended, but only if the standard is embraced.
How does balanced work in an amplifier? IE - compared to amplifiers that have XLR in but don't employ true balanced?
A fully balanced amplifier maintains separate signal paths for each of the two input signal polarities, all the way to its output terminals. So the negative or black speaker terminal is not connected to ground as it would be in an unbalanced amplifier, and is actively driven with a signal. The signal is similar to the one on the red speaker terminal, except that it is inverted.
An amplifier that is unbalanced/single-ended internally but has a balanced (xlr) input feeds that input into a differential receiver stage that has a single-ended output. That single-ended signal is fed into the rest of the amplifier circuitry, which is unbalanced.
Re the original question, several advantages (or at least theoretical advantages) of fully balanced design have not yet been mentioned. These include cancellation of some forms of distortion that may otherwise be generated internally; and, particularly in the case of a power amplifier, lower levels of power supply-related noise. There are some others as well. See this Atmasphere white paper.
My feeling is that both single-ended internal design and single-ended interfaces are inherently compromises, assuming equal quality, starting with the fact that in nearly all modern designs that have single-ended interfaces signal returns, circuit ground, chassis ground, and ac safety ground are all common. However, there seems to be ample anecdotal evidence that in most systems and for most people the degree of that compromise is either insignificant or is overshadowed by many other variables, one of which is price.
Balanced circuits only has an advantage if used as intended.
If the black box is truly balanced in designed circuitry, from source through final speaker out, then yes it should sound sonically quieter and better matched.
Cable design of a properly made single ended is three cables plus,common and shield. The common shares the path with the right and left negative part pf the circuit.
Cable design of a properly made balanced is four cables plus and negative on left and plus and negative on right which in return each conductor creates it own path and separation as intended.
When a company builds and manufactures a truly balanced source,pre-amp or a amp in practice the final outputs are two separate amp stages left and right that will be a true balanced design. Opposed to one that shares the left/right of the single ended circuit.
In theory and thought one would achieve balanced separation.
1) Less chances of phase shift
2) Higher gain
3) Less floor noise
4) Better and tighter connection with less chance of degregation.
Down size it is costly and debatable. A poorly designed balanced black box will sound less pleasing than a properly designed single ended circuit. Bottom line be aware and research carefully the company that so call design a truly balance components.
My amps have not only separate connections but separate curcuits for rca's and XlR. You have to switch curcuits when changing between the two and the paperwork says that the amp must be turned off.
I have amps that have been reported to run best in balanced mode, but I couldn't really hear a difference. These days my preamp (Herron VTSP-3A)does not have balanced outs so it is not even a possibility. With that said, I don't care, my preamp is the best one I have ever had and my system and I don't see not being able to run in balanced mode for my amp as a big deal as it sounds darn good to my ears the way things are.
One question about balanced and amplifiers. I know sources and preamps need to have true balanced topology to make use of balanced's advantages. Is this true when the signal reaches its final stage of electronics - the amplifier? Or is this where the balanced signal is ultimately converted to a simpler signal to drive the speakers? How does balanced work in an amplifier? IE - compared to amplifiers that have XLR in but don't employ true balanced?
There is no fundamental difference in sound quality between "balanced" and "single-ended" circuits. The major upside to balanced circuits is that they are less susceptible to correlated noise picked up by interconnects, ground loops and power supplies since the balanced circuit floats inside its own insulated world.
Agreed.
I would add that balanced usually has a higher signal level (pro audio).
I would add that ground loops are quite often a problem if you talk about audiophile quality with recordings that have tremendous dynamic range. However for your average Green Day of Red Hot Chilli Peppers hyper-compressed releases there is unlikely to be any audible difference between RCA and balanced.
All things being equal, truly balanced is no better than single ended. Without regard to any budget considerations I only use single ended.
My sources run through 3 stages of gain before reaching the speakers. Three triode tubes. I have no noise unless I put my ear up to my speakers. I see no reason to complicate things by adding a bunch of extra stuff.
As somebody said earlier this has been debated to death. I haven't read anything so far that hasn't been said in numerous threads, including what I said.
Theoretically, balanced design is quieter, though this does not mean it sounds better. Just as a more efficient loudspeaker does not mean it will sound better than a less efficient loudspeaker. The true balanced design will cost a lot more money, because you will have 4 seperate signal paths to follow opposed to the standard two paths of an unbalanced design. More paths = more parts = more costs.
So some "balanced" designs will not sound as good because they will use less expensive parts to compete finacially with the unbalanced designs. For example, using the same design and parts, and taking dealer mark up into account, a $7.5K truely balanced preamp will sound the same sonically as a $5K unbalanced preamp (in a area with low EMI/RFI issues). The total price wouldn't be double because they can used the same chassis and a similar power supply. OTOH, if both preamps are priced the same, the unbalanced design will have the advantage of being able to use better parts and should sound better, again, unless you live in a higher EMI/RFI area.
Now if you live in an area where their is high EMI, RFI or you have grounding problems, the extra cost for balance may well be worth it. If you live in a place where EMI, RFI and ground issues are null, than your money is probably better spent on an unbalanced design.
I've gone both routes, and neither one is right or wrong. I've found that in my system, fully balanced is slightly quieter, barely noticeable. I would say that I notice more noise levels between tube gear and SS gear than between balanced vs. unbalanced (I still prefer tubes). That said, noise is not really much of an issue in my system, and I'm currently using unbalanced gear. YMMV.
All things being equal, truly balanced is better than single ended, but at a cost in both money and effort. Due to budget considerations, I currently only use single ended.
05-30-10: Tvad: The merits...scientific and audio...the two are interlinked:
I think they are quite separable.
Lower noise floor due to EMI/RFI rejection
Only if there is EMI/RFI to reject.
Lower noise floor due to absence of ground loop hum
Only if there is a ground loop.
Better high end and low end extension and resolution when using long interconnects
Really? Why? In my main system, where there is no significant EMI/RFI or problems with ground loops, the 10meter SE and BAL connections are of equal quality. I just prefer the XLR connectors to the the RCAs.
Balance is only better if the signal from the source is balanced from the start, at the digital to conversion. I have owned several CD players & DACs that where that was the case and balanced did sound better. However I have owned a few CD players that had balanced output but the signal was split and inverted at the output stage that does not sound as good as single ended. It depends on the design. For a curve I have all single ended input sources, but between my Pass Labs XP 10 & my XA30.5 I use balanced. I have tried both balanced & single ended & I prefer balanced. Go figure
There is no fundamental difference in sound quality between "balanced" and "single-ended" circuits. The major upside to balanced circuits is that they are less susceptible to correlated noise picked up by interconnects, ground loops and power supplies since the balanced circuit floats inside its own insulated world.
In a single-ended system one side of the circuit is also tied to, and exposed to, the external shield. Thus, if currents flow through the external shields from one component to another the different components will end up at different voltages causing hum and other less clear cut effects. To create a quiet single-ended system usually requires choosing a single grounding point for one component and "floating" the other components. This is particularly important if a phonostage with very low-level signals is present. This floating can possibly lead to safety issues under some conditions where one of the floating components is disconnected from the rest system, and thus no longer has a true ground, but it is still under power.
The downside of a balanced system is twofold: As mentioned above, a true balanced circuit has roughly twice as many components and hence is more expensive. And, while usually not a practical issue, it has in principle more uncorrelated noise (by sqrt(2)).
I too use a system that is balanced, from all of my primary sources, (phono and CD), through the preamp and then on to amps. I do like how quiet it is, but I think that has more to do with the design of the equipment than with the cables themselves.
And I agree with all the others that the connectors (terminations) of XLR cables are better, (because they lock, and almost more importantly, unlock), than the standard RCA terminations. (And I dislike locking RCA terminations, because they tend to lock up after time and getting them to unlock is a pain in the butt.)
However, as has been mentioned by others, only equipment truly designed to operate as balanced, (and not merely equipment that has a converter to take the signal from single ended to balanced), are worth using in balanced mode. Certain equipment manufacturers make sure that their equipment is truly designed from the ground up for balanced operation. (Ayre comes immediately to mind as one such manufacturer, and it has been noted by various reviewers that their equipment sounds noticeably better in balanced versus singled ended.)
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