|WikiProject Professional sound production||(Rated Start-class, Mid-importance)|
deleted: "To reduce noise the metal chassis are interconnected, and shielded cables are so connected at the source end only. The use of battery power is good both for audio preamps and amplifiers." The claim about shielding is totally bogus. No cable is sold like that. Yeah, some people do it, mostly people with know background in electrical engineering. Try reading tech notes on rane.com for a more informed perspective. I assume the suggestion to use batteries is motivated by similar rumors about grounding. 126.96.36.199 01:41, 4 April 2007 (UTC)
- In pro use, with balanced connections, cable shield connected at only one end is fairly common, even sometimes in semi-mass-production cables. You can't feed a mic phantom power over a cable like that, which is why most have shield connected. It isn't necessarily gonna give you the best signal for interconnection of various fixed devices, though, since ground loops are very much real things. In non-pro audiophile-grade use, you often see cables with 2 conductors + shield (just like in a balanced cable), where the unbalanced signal and the return travel over the 2 conductors and the shield is *just* a shield, rather than the return, and in that case it's connected at only one end. Such a cable will still measure continuity between the centers and the outsides respectively of the rca plugs. i'm not sure if there's a measurable difference to ground loop performance. If there were I suspect more pro cables would be made as 3 conductor plus shield.188.8.131.52 01:33, 15 October 2007 (UTC)
Gain in volts
"The preamplifier provides voltage gain (about: 10millivolts to 1volt)" -- since when is gain measured in V? I suspect the article is trying to say (about standard hifi preamps) "provides voltage gain/reduction (output level: between 10 mV and 1 V)", but it's slightly unclear to me.184.108.40.206 01:33, 15 October 2007 (UTC)
"The preamplifier provides voltage gain (i.e. from 10 millivolts to 1 volt) but no significant current gain. The power amplifier provides the higher current necessary to drive loudspeakers."
- I'm not convinced of this statement. Preamps are for converting from high to low impedance. High impedance is voltage-based and the less current taken into the input the better because the preamp device reads the voltage, suppressing as much as possible a degradation of the output voltage signal of the instrument. An electric guitar for example produces very low currents, and the signal would be difficult to read by a low impedance device. Low impedance means that there is less resistance and so the input is more a current reading device. I'd say that the current gain from input to output from a preamp would be significant in terms of the current of the output divided by the current of the input. Of course that is not to say that there is not further significant current gain upon dividing the power amp output current by its input current. —Preceding unsigned comment added by Palomaris (talk • contribs) 22:44, 6 January 2010 (UTC)