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I see fully balanced as being like 4 wheel drive. Not everybody needs it. Many people who have it don't need it. Those who really need it can't do without. It adds extra complication and expense which under most circumstances is gratuitous overkill.
Just like 4-wheel drive, you don't know when you will need it. From my standpoint.... it doesn't add much complexity to have it as a standard interface. It would in multichannel systems simply due the the greater real estate needed for all the XLRs but in a 2-channel system the extra space is a non-issue. And as pointed out above you can use a single ended source and still enjoy many of the benefits. The Bill Whitlock papers are excellent and well worth a read. I'm using the THAT Corp. 1200 Balanced line receivers in a product now and they are completely transparent. They add about $10/channel to the parts cost which would translate to about $40 retail per channel but I pretty much find that cost irrelevant to high-end audio.Note... this isn't balanced all the way through the entire circuit. I'm only using it as an INTERFACE which is what it was meant for to begin with. The entire purpose of the Interface is to minimize the possibility of picking up external noise between pieces of equipment. Also note... . the THAT Corp 1200 and transformers still benefit unbalanced sources. Go read the white papers by Bill. He has done a series of training exercises for the AES and he advocates good design practices that have real value... especially if everyone would follow them.
I was wondering if you know if he has advocated bypassing the poor audio/mute circuits after the DAC chip in cd players? Afterall they only add 6db of gain (gain of 2) so the digital to analog chip output is already approximately 1 volt. Thanks.Cheers.
It's not a new term. "galvanic isolation" is a very, very old term. Borrowed from "galvanic action or corrosion", that's what happens when you bolt different metals together and drop them in salt-water.
We audio types get our knickers in a knot over all kinds of extraneous stuff, and the balanced / unbalanced debate, discussion, whatever is one more knot. I suspect running short (or minimal possible length), well constructed (note, I did not say expensive) unbalanced cables will, in an absolute sense, generate similar benefits to running balanced connections in the vast majority of home stereo systems. Balanced cables are found in commercial audio systems for a reason: WAAAY more variables to control for with long cable runs in public venues. In the home environment, for most systems, its likely overkill. If someone wants to go through the added expense of cabling up a balanced system for home use, more power to them. All of the equipment, from source to amp, should be of balanced design. The home environment had better be fully implemented to maximize the listening experience, to the level of being nearly a home studio environment that controls for correct system voltages and elimination of extraneous noises, so that the end user will be able to perceive the sonic benefits. Most home listening environments / systems likely don't meet these prerequisites.
One of the few times I've had to trace a hum in my system, I finally -- after much trial and error -- traced it to faulty unbalanced interconnects. They looked nice, but the hum went away after I replaced them. Such hum would've been eliminated by balanced interconnects, but this particular interface didn't allow for balanced interconnects.
Exactly.... when you design using a balanced interface and follow the standard grounding practices in designing equipment you can greatly decrease the chance of having a setup that picks up noise. It isn't like a magic cable that is going to generate some euphoric experience. It is purely and simply to minimize the chance of picking up external noise either due to ground loops, EMI or RFI generated airborne or conducted noise. You won't hear a difference and that is the entire point. You shouldn't hear a noise. Think for a minute how many times you read about people who have hum/buzz or other noise problems when hooking up equipment. You won't appreciate it until you are aggravated by not being able to connect two pieces of gear without having a noise problem. Properly designed balanced interfaces help increase the chance of doing exactly that with either balanced or unbalanced sources.
The simpler the system - like the vast majority of two channel home systems - the less likely there's any advantage to balanced operation. The more complex the system, the more likely you'll pick up and amplify sources of noise. In the extreme case where balanced design might be of benefit, let those folks pay for it if they want it. However, MOST home systems will never need or notice the absence of balanced design. Home theater systems are good examples of systems that MIGHT benefit from the use of balanced design. However, consumers that would pay extra for balanced design HT gear are by far the exception rather than the rule. There are also some reasonably effective aftermarket solutions for ground loops in an HT system that reduce the need for balanced HT gear. If you want it, go for it. To suggest that it would be an advantage, particularly in cost-benefit terms, to the majority of users systems is, to me, stretching it just a bit.
It cost $40/channel.... if that is cost prohibitive to you then I think we are talking about different consumers.
Not sure where the $40 per channel number comes from. Is that only the cost of cabling? Since the value of balanced connections is derived from a fully balanced system, and each component should ideally be connected via balanced cabling from source to amp, I suspect the cost of cabling would be higher. Now, if we're looking at the impact of the cost of components, then we're looking at selecting only components that allow for fully balanced connections from source to amp. Not only are we selecting components out of a much smaller universe, the cost of such components are on average at much higher cost to the consumer. So, for costing purposes, the cost of selecting only balanced gear would be factored in, and would likely bump that cost per channel number up by quite a bit. If we're looking at the Home Theater market, where its likely that balanced connections would make the most difference in a home setting, the HT gear that out there that's balanced only is typically quite high end. This is driven by the cost of construction of these components, and the market - based realization that the number of consumers at that end of the market is quite small. So, though I've not put pencil to paper to figure it out, at least anecdotally, I have to suspect that the number is in reality quite a bit higher than $40 / channel.
Contrary to the common perception you don't need to have the entire system balanced to reap many of the advantages. I'd point you to Bill's site and his application notes because the topic is too complex to cover in a forum post.http://www.jensen-transformers.com/apps_wp.html
It cost $40/channel.... if that is cost prohibitive to you then I think we are talking about different consumers. That is a worst case scenario too assuming parts cost, board space and connector interface. In real manufacturing volumes and figuring 50 points manufacture to distributor--50 points distributor to dealer/consumer you would be looking at $15-$20 retail per channel for the THAT Corp 1200 solution. For a standard line receiver (INA134/INA2134) without any of the 1200 series mojo you are talking a dollar in production quantities. Now.... figure the amount of tech support calls, unhappy customers and general support headaches associated with the times when your customers find they have a noise problem. If it prevents one in a hundred you may be money ahead and the consumer will have one less headache to deal with.
