SH, I agree with you regarding the balanced I/O. (my amp has balanced and unbalanced inputs. As long as it's close to the preamp, I go unbalanced) But, why would the extra step cancel out even-order distortion? Why would it cancel out anything? I would think it should *add* if anything.

The way I understand it, there are a couple of ways to design a balanced output. Either with a transformer or a differential driver circuit. Is one of those implementations prone to cancelling even harmonics (of distortion).

Cary

I would have to refer you to engineering textbooks to give you an answer about how a balanced circuit cancels even order distortion, but this type of circuit does do this, and leaves the odd harmonic distortion intact. This cancellation of the even order harmonic distortion occurs only within those stages which are balanced, and does not remove any distortion components generated within any preceeding or later stages which are unbalanced.

Technically, a true balanced circuit refers to one which uses a balancing transformer. This type of circuit is not referenced to ground. This circuit is rare today, even in professional equipment, because of the expense of high quality transformers.

What is now common is what is known as differential or electronically balanced, which achieves balancing by purely electronic means.

Both types however cancel even order harmonic distortion within the circuit.

Push pull output stages in power amplifiers also fall into this category, so that one stage will cancel even order harmonic distortion generated within that stage. Bridged power amplifiers are also a "balanced" circuit and would have the same sonic penalty.

Components such as power amps which are designed as balanced (differential) from input all the way through their outputs are the worst of all worlds, as the entire circuit path will only generate odd order distortion, and probably not sound very good as a result.

Soundhound: Thanks for the information - good to know. Seems to be a lot of "balanced is always better" misconceptions out there, or else a lot of people with monoblocks sitting 50' away from their pre-amps

As for the 990, to quote the esteemed Charles Brown: AAAAUUUUGGGGHHHH!!! Just when I thought I had figured out how to spend my tax return...

Seriously, this thing sounds (on paper, that is) SWEET! And the intro price is definitely better than I expected.

Is it official that it comes with the MX-700 for a remote? That's like $180 right there. And my MX-500 has a non-functioning "back" arrow, which is frustrating (mostly when controlling the Tivo). I think I'll have to start whining loudly about that button to the wife.

If the addition to my house existed beyond paper at this point, this would be a no-brainer. As it is, I'm glad the order form isn't up yet...I have a strict rule about not ordering things until I get the drooling under control.

I wonder if the internal circuitry is designed as "unbalanced" with add-on circuitry to accommodate balanced I/O, or if much of at least the analog sections have a "fully balanced" design? Likely what would provide the best possible fidelity, per Soundhound's comments.

I haven't seen anything official on the remote. I'd doubt it would be an MX-700 - it lists for $350 (close to a third of the 990's total price), although it sells online for around $180.

I would hope that the 990's internal design is unbalanced and that the unbalanced part of the circuit is available on RCAs, bypassing the electronic balancing part of the circuit for those who do not want to use the balanced feature.

If this is not the case, I would certainly not be purchasing one - if my ever 950 croaked, I'd look to a different brand.

It is more common for power amplifiers to be fully balanced from input to output. I would certainly stay away from these in favor of designs which are unbalanced with a bypassable balancing circuit on the input for those who absolutely have to use balanced cables.

The "balanced is better" mentality is pure marketing - big XLR plugs on the back of a component certainly do look cool, but cool looking is not always better.

SH, thanks, I'll have to keep my eye out for any info on distortion and balanced drivers/receivers. I can imagine that if you use a transformerless design for a diff. driver, which I believe is typically two identical opamps each driving the + and - signals of the pair, that there would be sonme cancellation effects. I'm just not sure what yet...

I would guarantee that the design is unbalanced throughout and only balanced at the balanced driver (at the end of the chain). I wouldn't worry about that.

The DVI switching is a nice feature, as is the video upconversion. However, I keep my video chain totally seperate from my preamp (950) and drive a projector directly from the HTPC so those aren't a deal-maker for me at least.

However, I really like the idea of the stereo sub outputs as well as other audio features (maybe better, or at least different, bass management, room eq?). I'm more interested in how it sounds though. If the design (and implementation) sound great, I'm definitely in on this one.

Cary

Thank god my ears are not that discriminating to be able to tell the difference in balanced and unbalanced distortion. As long as the darn thing sounds good to me...

Jeff

Keep in mind that the spec'd distortion levels on components means almost nothing. For starters, a manufacturer will never reveal the spectra of the distortion generated, especially if it consists completely of odd order harmonics. Additionally, in the case of power amplifiers, the distortion measurements are taken at higher wattages where the ratio of distortion to signal is greatest. If you look at the distortion verses output plots of most amplifiers, you will see that the distortion is much higher at low levels, such as around 1 watt, where most actual listening takes place.

A favorite manufacturer's argument is that since distortion is "so low" to start with, the fact that it is odd order doesn't matter. Nothing could be farther from the truth. Our ears can hear levels of 5th, 7th, 9th etc odd order distortion that "measure" in the .00x% range as a hardening and sterile quality to the sound.

In contrast, most people cannot hear 2nd order harmonic distortion at levels even exceeding 1% to 5% since the even order components are directly musically realated as the simple addition of octaves above the original frequencies.

Thank god I don't have your ears....