balanced is inherently flawed

Herman: All i can say is "great minds think alike" : )

I just posted or emailed someone stating much the same thing. Sometimes i do so much typing that i get confused whether what i sent was public or private.

The part that stuck out in my mind about balanced operation was primarily the fact that you have four amps ( or four circuits ) doing the work of two ( for stereo ). Most manufacturers have a hard enough time building two channels that match, let alone four that perfectly match. Not only does this increase the potential for a channel to channel ( left to right ) imbalance, but also that of inter-channel imbalance ( positive to neutral vs negative to neutral ). It is hard to achieve cancellation of spurious external noises when the amplifier circuit itself may not be properly "nulling" the offsets. Then again, some of these problems would show up in S/N ratio measurements if they were severe.

If the amplifier were not properly nulling the differenctial signal, the distortions produced from such a mismatch could be corrected relatively easily though by using more negative feedback. As many of us have heard though, this can make for a product that measures better but sounds worse.

What got me to thinking about this was the fact that i purchased an old amp to run the subwoofer i just finished modifying for my Father. This amp is internally bridged, which means that there are actually four mono amps making up the two stereo channels. This provides twice the voltage potential, making for a pretty potent amp in what is a pretty compact chassis. This type of approach shares similar design strategy to balanced operation, which is what got me thinking about the potential for internal imbalances.

As to El's comments, most of the Pro Sound reinforcement gear that accepts / works with balanced gear are simply using quad op-amps running in complimentary fashion. These cost next to nothing and one of these IC's can do both stereo channels. Most high end audio gear are using discrete components of ( hopefully )higher quality, making the parts count and cost of production measurably higher.

My thoughts are that balanced operation has the potential to work better, but like anything else, it has to be properly designed and implimented with good quality control. Otherwise, there's just more to go wrong. Sean
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PS... Lower grade circuitry may benefit more from balanced operation than state of the art single ended designs. At least with balanced operation, you've got some form of internal "checks and balances" without having to resort to GOBS of negative feedback.

Marakanetz: Diodes in themselves are "dirty" creatures and they too would require matching. Every diode has a different turn-on and recovery rate. Once again, you end up with more parts and more matching. Sean
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El: I'm not nearly as opposed to IC based circuitry as one might think. One of my favourite preamps is IC based. So long as good quality parts are used and the engineer / designer knows what they are doing, an IC based component can sound quite good. Problem here is that many products are based on the "sample circuit" that the manufacturer of the IC provided. Most of those circuits are designed to demonstrate the basic functionality of the IC, not exploit it to its' fullest potential.

Driver: Thanks for reminding me who i was talking to about what : ) I'm not even 40 years old yet and my memory is going. What's the next thing to fail??? : ) Sean
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1) A TRUE "balanced" design can swing twice the voltage potential of an identical single ended circuit. The gain of such a circuit is not necessarily twice as high ( a lot of other factors here ), but offers greater power potential with the associated increase in headroom. There are designs that operate on a differential mode, but aren't "truly" balanced as most engineers / designers think of them.

2) "Internal noise generated in differential circuits tends to be less then that of the same circuits executed single-ended. In theory, about 6DB less, so in two stages of gain, this could be 12 db less! This is dramatic."

Notice that Ralph says "in theory". In reality, these figures are typically not achieved. There are improvements, but not to the extent mentioned. Quieter and cleaner IS quieter and cleaner though. Whether or not the benefits will be noticeable is obviously dependent on how good the original single ended circuit was to begin with. Hence my previous comments about "poorer" single ended circuits benefitting most of the additional noise cancellation of balancing. When you've got a relatively high noise floor ( compared to a quieter design ), lowering that noise floor is always beneficial. Whether or not going into the added expense of balancing such a circuit is a worthwhile investment compared to designing a better single ended circuit ( with a drastically reduced parts count ) is a matter of personal preference / budget for the designer / manufacturer. As a general rule, balanced designs typically require appr twice the parts count as that of single ended designs. Many will argue that "simpler is better", but obviously, that is a subjective opinion.

3) I agree with you here Ralph, but that is IF the rest of the system is up to snuff. Since most gear / systems are compromised in design integrity, the benefits of "true" balancing are many times not achieved in lesser systems with lower grade components. As you mentioned though, "Balanced amps built from the ground up sound better with balanced inputs for the simple reason that balanced sources sound better!". This takes into account "proper design" from beginning to end, not trying to impliment a superior design into a system based on lesser design integrity.

As a side note, our AC systems are "balanced" as transmitted and DC is single ended. While Eldartford has commented on low loss DC transmission over extended distances, there is a reason why AC was selected over DC. That is, with twice the voltage swing and multiple phases, loss is drastically reduced and the signal is kept cleaner over a longer distance. DC is both lossier and more susceptable to interference. On top of that, RFI is very easily superimposed on top of a DC voltage. That's why even after the AC mains have been rectified in the components power supply, you can still have RFI being passed into the circuit. As such, the installation of some type of "trap" or even "snubber caps" in a typical power supply can really clean things up.

4) I didn't really read much into Herman's response here but I should have. All sound is created by displacing air, causing both a pressure front and pressure drop i.e. a positive and negative. Strings move fore and aft or side to side, percussion instruments are compressed and then rebound, etc...

Other than that, i don't think that Herman has been a "great source of misinformation". I think that Herman has contributed many factors along the way that were both valuable and factual along with quite a few personal observations. Obviously, nobody is going to agree with someone else ALL the time. Rather than making a generic and cumulative statement such as "The bottom line is Herman is a leading source of misinformation", one should jump in and present rebuttal at the time that the statements are made or when first "stumbled across". This keeps everyone on the same path in the same time-frame without offering much time between the "misinformation" being presented and / or the possibility of it being futher distributed. In effect, "rebuttal" acts as a form of "damage control".

I'm not getting down on you Ralph as i surely appreciate your input. I wish folks like you came around more often. If you've read any of my previous posts making mention of you or your designs / gear, i think that you know that i have the utmost respect for you and what you offer us as audiophiles. Other than that, feel free to put your boot in my ass as needed : ) Sean
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Herman: A cymbal moves up and down to displace the air. The rate that it displaces air is called the frequency and the volume of air displaced is the loudness or amplitude.

Just as the cymbal is pushed down and displaces air in that direction, the other side of the cymbal swings up and displaces air in the opposite direction. It is an equal and opposing force. If we didn't maintain the equal and opposing force, we wouldn't mantain consistent air pressure. If we don't maintain consistent air pressure, we start to develop a state of vacuum. The greater the vacuum that we develop, the less air that we have to displace. When we don't have air to displace or air to replace what has been displaced, we have total vacuum. If we have total vacuum, we don't have sound. Therefore, sound is generated by moving air in a balanced format.

Our ears work the same way. That's why our ears "pop" as we change altitudes rapidly. The pressure inside our ear is not equal to the pressure outside due to the varying densities of air, creating an imbalance. Once the pressure is fully balanced inside and out, our hearing returns to normal and we no longer have "popping" taking place. Sean
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One thing i'd like to add here. If Ralph wasn't wearing his affiliations on his shirt pocket ( Atma Sphere products ), nobody would have known who he was or why he might have the very strong point of view on the subject that he does. Due to the fact that he designs / manufactures audio gear that is balanced, an intelligent person would realize that he has a vested interest in protecting / promoting those interests. As such, comments made by someone in that position may be viewed in a slightly different light. This is not to attack or belittle the input from Ralph or any other manufacturer / designer / retailer / distributor, etc.. on any given subject, only to demonstrate how important disclosure of affiliations is. There is nothing wrong with sharing an opinion / point of view, regardless of who agrees or disagrees, so long as it is truly honest and not designed to manipulate others for one's own personal gain. Given the mess that we have going on in another thread about this subject, i thought that this was a perfect time to point out why i did / said what i did over there and why this thread hasn't turned into much the same mess. Those with ethics have nothing to fear when contributing to this or any other forum and i hope that they will continue to do so, both on a regular and long term basis.

Now, back to our normal program. Sean
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Bob: I understand that sound doesn't move air, the air simply "transports" the energy of the sounds created. Most people don't understand that, so i tried to word it in a way that was easier to follow. It is good that you mentioned this though, because my "simple analogy" could be considered "misinformation" if one were to take it word for word. Thanks for the clarification.

"To use your cymbals as an example, it is not the movement of the cymbal up and down that causes the sound - a single unstruck cymbal moving does not make a sound:

This is incorrect. Anything moving is creating sound because that movement imparts energy into the air. Whether or not that energy / sound is of high enough amplitude or at a frequency that we can hear is another matter.

" but the vibration of the metal cymbal as it is struck that causes the air pressure to vary as described before"

This supports my comments above. The only variance between the unstruck yet moving cymbal and the cymbal that was struck is the intensity of the movement generated and the frequency of excitation. Add the resonant and transient ( rise and fall ) characteristics of the cymbal to this movement and you have a specific sonic trait.

"In fact, if we move the 2 cymbals towards each other but stop their movement before they touch, we will move a lot of air but there won't be any sound."

False. There is sound, but it may not be of high enough amplitude or high enough in frequency for us to easily hear. If you doubt this, take a large yet solid lightweight item and move it back and forth in the air making long and slow excursions. You might not hear anything even though air is moving. Moving the item back and forth at a faster rate ( like "fanning" yourself ) will produce sound that is more audible and centered at a higher frequency. Same thing is taking place in both examples, the only variances are amplitude and frequency.

"The ear responds to varying pressure, not air flow or movement, after all if the air is moving, where is it going in the ear?"

Herman and i discussed this somewhat privately via email. Neither of us will argue this point. Sean
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Filtering of the ground can be beneficial if properly implimented, but it also increases the potential for reduced safety. By placing filter circuitry in the path to ground, you limit current capacity. In the event of component failure or an electrical problem ( severe surge or spike ), the filter circuitry could become damaged, opening the safety path to ground. Obviously, this is not good and i don't think that you'll ever see any design using such an approach obtaining UL approval. That's because something like this could literally be a matter of life or death. No manufacturer with any brains wants to risk something like this.

Having said that, providing the shortest, lowest series resistance path to ground that you can is the next best thing that you can do short of creating the above mentioned safety hazard. As i've mentioned in other posts, having someone that knows what they are doing clean and weatherproof your ground connections can sometimes make a world of difference. Most ground connections that i've seen from the AC mains to Earth were severely corroded, offering very poor conductivity. If conductivity to ground is reduced, any noise / RFI that was shunted to ground elsewhere in the house can now find its' way into your audio system. As such, maintaining your ground connection would not only be safer, it could reduce grain and glare while lowering your noise floor.

By the way, wasn't Dejan the guy that was shilling some specific PLC's that he was associated with over at Audio Circle? Sean
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Two things Ralph.

"Not that I'm saying that SE is bad, just that balanced (done right, which is not that hard) is better and *any* audiophile can hear it. I had a girlfriend who was deaf in one ear, and half deaf in the other, and *she* could hear it, so I am confident you can too if it give it a straight shot."

Someone that is highly respected, both within the Audiogon forums and audio industry on the whole, publicly commented that they did not like your preamps at ALL. On top of that, the preamp that they ended up running is being utilized in single ended mode. Given that they've run your amps and found them to be a quality product, how would you respond to that?

As a side note, a reduction in noise of -18 dB's is equivalent to having 1/64th the noise floor that you started out with. As Herman points out though, if the noise floor is already well below audibility, how much of a benefit is it?

There's another thing that you're overlooking Ralph. That is, ALL amplifier / speaker interphases are "single ended". Why this is, i don't know.

If you think about it, a "balanced" dynamic driver would be simple to make AND offer drastically improved transient response. By using two coils in parallel ( one positive and one negative ) and driving them with a common center tap ( ground ), you would literally have ( near ) instant acceleration and deceleration potential. When one motor was pulling, the other would be pushing, etc... They would end up sharing the load AND cancelling out / drastically reducing the effects of reflected EMF. Why hasn't anyone done something like this? While it would take an all new speaker AND amplifier design, i see no reason why it couldn't be done successfully.

Once again, the "high end" and "high tech" audio engineers / manufacturers "sleeping on the job". Sean
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PS... I'm a "more is better" kind of guy, so i'll take any reduction in noise / increase in power that i can get. Having said that, only one of my systems is running in balanced mode.

PPS... An E-stat would lend itself to "balanced drive" also with no need for a transformer. One could use high voltage output devices in the amplifier and directly charge the two plates and mylar. By varying the positive and negative potential between the plates, the mylar, which would be grounded, would be repelled and / or attracted uniformly across the entire sheet in both directions. Only problem here is that you would have one helluva safety hazard to deal with when energized / playing music.

Ralph: There are points that i'd like to respond to on your comments pertaining to the amp / speaker interphase, but i'm going to refrain from doing so for now. I've got my reasons and it has nothing to do with you, your company or your products. As i've mentioned before, i like many of the design aspects and sonics generated of the Atmasphere amps.

As to DIN connectors, as far as i'm concerned, they are the worst audio related connector on the market. I don't care if the "technologically advanced" aka "perfection oriented" Germans invented them, they make a poor connection, are not rugged, lack reasonable spacing between conductors, increase the potential for crosstalk between channels / circuits, are difficult to assemble if working with anything above hair-fine wire, etc... To keep things in perspective, some of my Quad gear uses them. The only reason that i can see that a company would want to use a connector like this is that it minimizes clutter ( Quad gear is typically very small ) and that it "almost" makes one choose products from the same manufacturer due to connection compatability. This guarantees the manufacturer that the unit will be working with suitable support components ( probably their own ) and increases the potential for more sales of their own gear. Then again, the reverse part of that equation is that they end up losing sales due to lack of universal connections. Either way, i HATE those damn DIN plugs!!! Sean
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