What's the next thing to fail??? : ) Sean
You don't want to know brother. hehe
Cheers,
John
You don't want to know brother. hehe
Cheers,
John
balanced is inherently flawed
A recent post asking for opinions on balanced vs. single ended got me thinking once again about the inherent flaws in a balanced scheme.
A balanced signal has 2 parts called plus (+) and minus (-) that are equal in voltage but opposite in polarity. Therefore a balanced amp is really 2 single ended amps in one package, one for the + singal and the other for the - signal. So a balanced amp using the same quality parts as a single ended amp will be twice as expensive. Strike one.
That brings us to the "equal but opposite" notion. In order for this to work as planned, all of the + stages and cables connecting them must be exactly equal to all of the - stages all the way through the source, preamp, and power amp. Any deviation from the + stage being the exact mirror image of the - stage will result in an imbalance. Since perfect symmetry cannot be achieved, especially with tubes, distortions are introduced. Strike two.
Some think that balanced has to be better for various reasons that include:
1. If they hook up a balanced device using single ended cables they loose some gain.
2. They think a balanced system can achieve a lower noise floor.
3. They have balanced equipment and it sounds better when they hook it up with balanced cables vs. single ended cables.
4. It's used in recording studios by the pros so it must be better.
These arguments are flawed for the following reasons:
1. More gain does not equal better sound. Of course you need enough gain to drive your speakers to satisfactory levels, but the fact that one connection has higher gain than another has really nothing to do with sound quality.
2. This is the most misunderstood of all. A balanced amp CAN reject noise that is coming in through the interconnects. However, it can do nothing to reject or cancel the random electrical noise that comes from within the devices inside the amp. A balanced amp has no advantage over a single ended one when it comes to the major contributor of noise in the system, that which is generated inside the amp. The rejection of noise from cables relies on the fact that it is generally equal to both the + and - inputs and is therefore cancelled, but since the noise voltages generated by the devices inside the + and - stages in the amp are random and unrelated, they do not cancel and are passed on to the next stage.
Furthermore, since well designed, shielded interconnects of any type are very good at rejecting electrical noise from the outside, balanced has no advantage except in very noisy enviroments or when using very long runs, both of which apply to recording studios, not to typical home systems.
3. Since a truly balanced amp was built from the ground up to operate in a balanced mode, it makes sense that it will sound worse when fed a single ended signal. That doesn't mean that balanced is better, just that that particular amp sounds better when fed a balanced signal.
If you subscribe to the theory that more money can get you better performance, and since a single ended amp has 1/2 as many components as an equivalent balanced amp, it stands to reason that if the designer put as much money and effort into designing a single ended amp, it would sound better.
4. See 2 above.
And this brings us to our last point. ALL sound sources are single ended. Whether from a plucked string, blowing air through a horn, the human voice, or anything else; the resulting increses and decreases in air pressure that we perceive as sound are single ended. There is no "equal but opposite" waves of pressure. This is also true when the signal finally gets to a loudspeaker. There are no "equal but opposite" pressure waves coming from the speaker. It is a single ended device.
In a balanced system these pressure variations are picked up by a microphone and then some where along the line converted to balanced. A phonograph record is encoded single ended as is a digital disc. Your CD player may have a balanced output but the data that is read from the disc is single ended and then converted. In order not to introduce ditortions, this conversion from single ended to balanced has to be done perfectly. And since it can't be, strike three.
A balanced signal has 2 parts called plus (+) and minus (-) that are equal in voltage but opposite in polarity. Therefore a balanced amp is really 2 single ended amps in one package, one for the + singal and the other for the - signal. So a balanced amp using the same quality parts as a single ended amp will be twice as expensive. Strike one.
That brings us to the "equal but opposite" notion. In order for this to work as planned, all of the + stages and cables connecting them must be exactly equal to all of the - stages all the way through the source, preamp, and power amp. Any deviation from the + stage being the exact mirror image of the - stage will result in an imbalance. Since perfect symmetry cannot be achieved, especially with tubes, distortions are introduced. Strike two.
Some think that balanced has to be better for various reasons that include:
1. If they hook up a balanced device using single ended cables they loose some gain.
2. They think a balanced system can achieve a lower noise floor.
3. They have balanced equipment and it sounds better when they hook it up with balanced cables vs. single ended cables.
4. It's used in recording studios by the pros so it must be better.
These arguments are flawed for the following reasons:
1. More gain does not equal better sound. Of course you need enough gain to drive your speakers to satisfactory levels, but the fact that one connection has higher gain than another has really nothing to do with sound quality.
2. This is the most misunderstood of all. A balanced amp CAN reject noise that is coming in through the interconnects. However, it can do nothing to reject or cancel the random electrical noise that comes from within the devices inside the amp. A balanced amp has no advantage over a single ended one when it comes to the major contributor of noise in the system, that which is generated inside the amp. The rejection of noise from cables relies on the fact that it is generally equal to both the + and - inputs and is therefore cancelled, but since the noise voltages generated by the devices inside the + and - stages in the amp are random and unrelated, they do not cancel and are passed on to the next stage.
Furthermore, since well designed, shielded interconnects of any type are very good at rejecting electrical noise from the outside, balanced has no advantage except in very noisy enviroments or when using very long runs, both of which apply to recording studios, not to typical home systems.
3. Since a truly balanced amp was built from the ground up to operate in a balanced mode, it makes sense that it will sound worse when fed a single ended signal. That doesn't mean that balanced is better, just that that particular amp sounds better when fed a balanced signal.
If you subscribe to the theory that more money can get you better performance, and since a single ended amp has 1/2 as many components as an equivalent balanced amp, it stands to reason that if the designer put as much money and effort into designing a single ended amp, it would sound better.
4. See 2 above.
And this brings us to our last point. ALL sound sources are single ended. Whether from a plucked string, blowing air through a horn, the human voice, or anything else; the resulting increses and decreases in air pressure that we perceive as sound are single ended. There is no "equal but opposite" waves of pressure. This is also true when the signal finally gets to a loudspeaker. There are no "equal but opposite" pressure waves coming from the speaker. It is a single ended device.
In a balanced system these pressure variations are picked up by a microphone and then some where along the line converted to balanced. A phonograph record is encoded single ended as is a digital disc. Your CD player may have a balanced output but the data that is read from the disc is single ended and then converted. In order not to introduce ditortions, this conversion from single ended to balanced has to be done perfectly. And since it can't be, strike three.
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- 73 posts total
Herman. I really apologize for your computer mishap. I should of stated that the first link is an Adobe PDF file. My bad. I have provided the actual web link below in hopes that you may read the white paper contained within. It is some fascinating and extremely insightful reading. http://www.jensen-transformers.com/an/an003.pdf I agree that we all tend to experience a "slant " or "bias" when absorbing information being provided by manufacturers. I try to negate the sales portion of the information and concentrate on the rational scientific or factually supported portion of the information. Remember. Remove the sales portion, and in most cases the information is still being provided by brilliant and very well acomplished designers and engineers. Let's mentally remove the corporate logo's, and give them the credit and respect that they deserve. Driver. My background and formal education was mechanical engineering. Throughout the time I was attending school, I was an avid listener and musician. So, I had exposure to the prosound industry. Two of the most brilliant designer engineers I ever aspired to due to that exposure were Robert Heil and James B. Lansing. These gentleman could be considered modern day pioneers of audio research and design. I hold tremendous respect for both of these individuals. If one was to read Robert Heil's white papers on sound reproduction, my feelings would be reinforced. And now the absolute bottom line (for me at least). When I put together my last system I had initally hooked everything up with LAT IC-200 interconnects utilizing RCAs, as I had no balanced interconnects. I ordered new ICs (same exact cabling) in balanced configuration. Upon switching all IC cabling to the balanced wires, (transport to dac, dac to amp, all TRUE balanced) the difference in quieting factor was astonishing. And my system was already extremely quiet from the start. It's very simple. More quiet. Lower noise floor. No impedance level mismatch. (TRUE balanced) Equals: Wider dynamic range. Higher level of detail (less noise). Happy components. (VERY scientific) These are MY results with MY system. Respectfully, Ed. |
Thank you Herman. I often have a hard time deciding which sound is more pleasing to the ear, "Kind Of Blue" through the YBA, or 390 cubic inches rumping away on 110 octane Cam-2. The motors in both of those cars are being run "full balanced", but it doesn't make them any quieter. The YBA is less octane sensitive. :>) |
Hi folks, Hate to bring this up but all of Herman's arguments are completely flawed! As you might expect me to say, but all I have to say is, if you've not tried it, you have no idea what you're missing. I'll give you some examples (refer to the leading post above): 1.> This is inherently wrong, as balanced does not have inherently more gain. It has the same gain, just with less noise. 2. This is the most misunderstood of all... It appears that this in one of the things that Herman misunderstands the most. 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. Additionally, differential balanced circuits can also reject noise in power supplies. This is called Cross Mode rejection, and is a spec, in addition to Common Mode rejection, that all active balanced circuits have. 3> sheesh... Balanced amps built from the ground up sound better with balanced inputs for the simple reason that balanced sources sound better! This is because of various things, but a good example is that balanced cables can deliver the signal better. If you don't believe me, look at the phone company. Before balanced lines existed, transcontinental phone service was impossible. That is because of all the losses that are are associated with single-ended systems. When balanced line came in, so did long distance. The same benefits work well in the home too, as balanced connections send the signal from one component to another with far less interference from the cables! 4> double sheesh and Geez... Finally, here are some balanced sound sources: All phonograph cartridges (with the exception of certain ceramic cartridges and the old Decca cartridge). All tape heads. All decent microphones. All LPs are cut with balanced equipment. Most CDs are mastered this way too. In fact, 99% of everthing you listen to had balanced circuitry as part of the signal's makeup. Mercury Records could never have made all those recordings without balanced lines as in some cases they had to run the mic cables over 150 feet. Same for RCA, Decca, EMI, in fact nearly every record label in the world. The bottom line is Herman is a leading source of misinformation. Sorry to say it, and if y'all want to look at my previous posts you'll see I try to not flame people, but this sort of blather can't go unchallenged. Forums like this should be about the truth for God's sake and ours. |
- 73 posts total