[JLM]

In shopping for DAC's, pre-amps, power amps some of better stuff is balanced (mostly solid state).

Why mostly solid state?  (My guess is because of the studio/concert roots of balanced design for long/parallel cable runs and this sort of application goes along with solid state.)

Some reviews mention lower noise when pre/power amps are connected via balanced, why?

And I've read that signals from single ended sources are ripped apart inside any amp, true?

TIA

[Larkston Zinaspic]

Ralph Karsten has said that the Atma-Sphere MP-1 was the first high end audio balanced line product introduced to the audiophile market in 1989. He may chime in here, but below are a few quotes I picked up elsewhere.

If you know only one thing about the balanced line system, the thing to know is that its purpose in life is to eliminate interconnect artifact!

In order to do that the equipment that the cables are used with has to support the standard: pin 1 is ground, pin 2 is non-inverting, pin 3 inverting, but most of all whatever is driving the cable should be able to drive a 600 ohm load without ill effects, which is how all the cable artifacts are swamped out. Most high end audio manufacturers don't get that last part.

IOW if the standard is met, the cable and its length will hardly affect the sound at all- and will be far more accurate than single-ended. So if you are hearing big differences between cables, that is an indicator that you are not getting everything out of them they have to offer.

RCA cables have a connection standard, but no termination standard. Balanced line has a connection standard, but also has a termination standard, which is 600 ohms. It is that low impedance which makes the difference. If your source has a high output impedance, it can't swamp the effects of the cable and so the cable artifact can be heard. That's not taking advantage of everything that balanced line has to offer.

That reality is simply that when you ditch the termination standard, the cables will have an artifact.

[nickd]

Larkston is quite correct. balanced done right (600 ohm) has a much lower noise floor. Three companies have taken the standard even futrher. Krell with their CAST interface, darTZeel with a 75 ohm interface and PBN Audio with a 50 ohm interface. Those three companies take it to the next level but also have prices to match their modest sales volume and high development costs.

I have found very few preamps that can truly drive a 600 ohm balanced input. Most designers use a buffer in the input to raise the amplifier input impedance to 150k to 200k ohms, easier do drive for sissey preamps but up comes the noise floor and down goes the resolution. One of the better values on the market is the Parasound JC2. A little lean sounding overall but the noise floor and soundstage are to die for. Used on Audiogon for about $2500. It's a sweet deal for the ultra highend.

[Speedskater]

Except that:
a] Pin #1 is to the chassis not to the circuit ground.
b] You would be hard pressed to find much equipment manufactured since 1970 designed to 600 Ohm input/output termination standards.