The preout terminals look very close together on the 950. Does anyone know if it will cause a short if two of the metal sides of the interconnects themselves touch each other?

The shells of the interconnects are the circuit ground, and they can touch each other, or the chassis of the 950 without any problems. It's the small center pin that shouldn't touch anything else but the inside of it's jack.

The shells are ground but the signal is AC, so isn't the ground side carrying the signal half the time?

The signal is NOT AC. AC involves a constantly moving waveform. The ground provides a base -- the signal at any given time is a DC value above the ground. The higher it is above ground, the louder the signal.

In AC circuit, the voltage goes both above and below ground, like -120 to +120V. An audio signal on the interconnects will vary from 0V to something like +2V.

bigmac,

Thanks for the info. Speaker wires carry AC though right?

I guess that explains why the shield can be part of the circuit (ground) and still work. Otherwise the shield could pick up radiated noise and put it directly into the preamp signal.

Nope, speaker wires are DC, too -- same basic signal principle as interconnects, just mo' power flowin'. You can disconnect your left ground wire, tie it into the right ground, and your speakers will still work.

All signals, low level through interconnects, or speaker level, are AC. Most or many preamps are AC coupled, meaning there is a cap in series with the output to make sure no DC gets through. This ensures there will be an AC signal. And speaker level signals had better be AC; or the DC level will burn out the voice coils.
Mike

I'm not going to dispute what you're saying, but an audio signal _is_ AC (alternating current). It is referenced to the circuit ground, but is not correct teminology to say that it is DC (direct current). If you say that an audio signal is DC around an engineer, he (or she, or it) will respond with 'huh?'
It is not DC since it is constantly changing, DC is defined as a static voltage that doesn't change (at least much).

I know, I know, that arguments can be made to the contrary, but these are the generally accepted definations of AC and DC, except in some parts of West Los Angeles.

This can be true of a single-ended gain stage or DAC output within a piece of equipment, but no RCA jack should ever output a DC voltage. To amplify previous comments (no pun intended), a DC voltage is defined in linear systems theory as the constant or non-sinusoidal component in an FFT decomposition of a signal. A signal which varies between 0 and +2 volts has a +1 volt DC offset; whatever sinusoidal components (sounds) are carried through such a signal are the AC components.



This is not related to whether the signal is 0 to X volts or -X/2 to +X/2 volts. In either case, the ground terminal (interconnect or speaker) serves as the constant voltage reference. Moreover, for balanced amplifier topologies such as the Pass X series, you can't do this, because the "black" and "red" terminal voltages vary in equal and opposite directions.



Hehe... Among the silliest things I've ever seen was a heated debate (after many, MANY drinks) between two electrical engineers arguing about whether AC or DC was the proper indication of "which side of the fence" they were on. It turns out that, after five minutes or so of banter, to both's surprise, they were on different sides of said fence.