A question about true balanced differential design signal paths.

[painted_klown]

As the title suggests, I have a question about a true balanced setup.

 

In order to have a fully balanced setup, at what point does everything in the signal path need to be balanced?

 

For example. If I buy an Oppo BPD-95 and use the stereo XLR outs, into a true balanced preamp, and then run that out (via the balanced XLR analog outputs) into a dual differential amplifier, then I know 100% that my signal is a true balanced signal through the entire signal path.

 

For example B, lets say I have the Sony PS3, and run an optical (toslink) cable to an Emotiva XDA-1 fully balanced DAC, and then from the balanced XLR outs into a balanced amp.

 

Would example B still be considered a true balanced signal path since when it gets converted to analog, it is done with a true balanced DAC?

 

Example C. Say I buy a Musical Fidelity V-Link, and run a USB cable to the V-Link, then I run the V-Link into the Emotiva XDA-1 (via either toslink or digital coax), and then the XDA-1 balanced out into a fully balanced amplifier.

 

Would example C (similar to example B, but with a different source of signal origination) be considered a true balanced signal path all the way through?

 

I guess my question comes down to this: In order to have a true differential balanced signal chain from bits (of information) to amplifier, does the source (if digital) need to be "designed from the ground up" to be considered fully balanced, or does that only matter after the conversion from digital to analog?

 

I hope what I am asking makes sense. I am really curious about how this works, and what constitutes a 100% true balanced signal for the ENTIRE length of the signal chain.

 

Thanks.

[Julf]

In order to have a fully balanced setup, at what point does everything in the signal path need to be balanced?

 

Depends on what definition of "fully balanced" you want to use. I don't thin there is one, single, universally accepted definition.

 

I prefer to talk about "differential" when talking about interconnects and inputs - a differential input is one that has a non-inverting input and an inverting input, both distinct and independent of signal or chassis ground, and the input signal is taken from the difference between the inputs. To get the benefits, it is enough that the input stage is differential, but some designs carry the differential construction further along the circuit.

 

Then you have "symmetric" circuits, with independent, identical amplifier stages for the positive and negative half-wave, but that is a completely different thing.

 

This whole discussion only makes sense for analog circuits. Yes, there might be differential and balanced parts of the digital chain (USB and ethernet are good examples) on the actual signal level, but that has again nothing to do with what happens after the DAC.

 

What I have to ask is what do you want to accomplish by a supposedly "100% true balanced" system?

[painted_klown]

What I have to ask is what do you want to accomplish by a supposedly "100% true balanced" system?

 

I currently own Emotiva XPA-1 mono block amplifiers. The ones here XPA-1 | 500W Mono | Emotiva Audio | High-end audio components for audiophiles and videophiles, spanning 2-channel music systems, as well as 5.1 and 7.1 home theaters. Products include multichannel amplifiers, stereo amplifiers, and monoblock amplifie

 

I know that there is a lot of debate about weather or not a fully balanced system makes any "real word" (ie, you can identify it in a double blind A/B/X test) difference, but the supposed benefit is a lower noise floor (that translates into a better signal to noise ratio), and better control over your speakers (the drivers).

 

Since I already own the amplifiers for a fully balanced system, then I would like to put a fully balanced signal path in front of them. To be honest, my main reason is "just to do it"

 

Would I be able to hear a difference in a blind test? Probably not, but this is audio we're talking here. Sometimes "logic" goes out the window (so to speak) for the sake of "mental satisfaction". I feel that I spent quite a bit of money (to me 2 grand for a couple of amps is a lot of money) and I am not even really utilizing their design.

 

I could have bought different (non-balanced) amplifers and saved some cash, but I just wanted to see how they sounded (amazing, BTW) so now that I have had them a while, I want to use them "properly".

 

So, I suppose the quick answer comes down to that I am trying to accomplish "mental satisfaction".

 

I hope that makes sense, in an audio geek kind of way.

[painted_klown]

Here is a link to the review that ultimately convinced me to purchase them.

 

Emotiva XPA-1 Monoblock Power Amplifier - Secrets of Home Theater and High Fidelity

 

I do not regret that purchase at all.

[esldude]

Whether a level you can hear, balanced connections will lower the noise floor, and in a measurable way. Also less prone to pick up stray interference. So there is no downside. Some people for years have felt when the option is available quite modest balanced cabling is equal to or better than expensive single ended cabling.

 

As for a truly balanced system who cares. You have what you have. Each part you use balanced lowers the noise floor a bit. If I understand your equipment, you will benefit from going to balanced connection. Your amp is already a differential output amp with no ground I think. So quit worrying about it and do it.

[Julf]

I currently own Emotiva XPA-1 mono block amplifiers.

 

Interestingly, despite the fact that they call it "fully balanced", the only aspect that they specifically state is balanced is the input stage.

 

I know that there is a lot of debate about weather or not a fully balanced system makes any "real word" (ie, you can identify it in a double blind A/B/X test) difference, but the supposed benefit is a lower noise floor (that translates into a better signal to noise ratio), and better control over your speakers (the drivers).

 

The lower noise floor is a result of a differential input. That is really the only part where you will see a benefit. A symmetic output stage is a common topology, but has little to do with "fully balanced".

 

Since I already own the amplifiers for a fully balanced system, then I would like to put a fully balanced signal path in front of them. To be honest, my main reason is "just to do it"

 

And that is of course a fully valid reason - the reason I was asking was that your solution looks different based on what you want to accomplish. As I tried to indicate "100% fully balanced" is mostly a marketing term, that is not unambiguously defined. But as long as you feed your amps from the differential outputs of the DAC, using XLR cables, you are as balanced as can be.

[Julf]

Here is a link to the review that ultimately convinced me to purchase them.

 

Emotiva XPA-1 Monoblock Power Amplifier - Secrets of Home Theater and High Fidelity

 

I do not regret that purchase at all.

 

And of course there is no reason to regret it. That link helps to clarify it is a H-bridge configuration. As you say, benefits might be debated, but as esldude said, as long as you feed it over a balanced connection from your DAC, you have the ideal configuration.

[painted_klown]

Awesome!

 

Thanks for the input and explanation guys!

 

I will admit that I am not well versed in electronic engineering and things, that's why I was asking the question. Even the stuff you are explaining is going over my head a bit.