Question about line out...

[bluzmn]

Should I use a shielded or unshielded cable for a line out from an amp to a PA (or other amp)?

[madkatb]

It's a signal source so use shielded.

[allende]

Do you mean what sort of cable to run from an amp's line out to the PA or other amp (in which case just use a shielded mic cable), or are you asking what sort of wire or cable you should use for adding a line out jack? If it's the latter, the best way is with no cable at all. If there's room in the chassis, add a line out jack next to the speaker jack; connect the 2 tips (hot) with a 33k resistor; connect the tip of the line out jack to the sleeve (ground) of the speaker jack with a 5k (anything from 3.3k to 5k is good) resistor; and connect the sleeves of the two jacks with a short wire. You've just created a voltage divider which knocks the speaker level voltage back to something a PA or amp input can handle. The specific resistor values don't matter that much, you just want a ratio of 10:1 or so. Some like to use lower values, ie 2.2K and 270ohm, as too high a value for the dropping resistor can attenuate high frequencies--but since my amps are built for harp, that's not a bad thing for me, and 33k/5k seems to work well. BTW, if you're running more than 20' from your line out to the PA, you'll need to go into a DI box and then use a balanced (XLR) cable to the PA's mic input for best results.