Speaker Cables

[zeh]

Hey there , Could anyone explain me whats the difference between normal jack instrument cables , and speaker cables ? I was told That I shouldnt connect my amp to my speakers with normal instrument cables (but It works) , and that I should Use speaker cables , Whats the difference?

Thank you

 

[Droog]

Because instrument cable is sheilded and increases ohm load to your amp in a huge way, makes it work way too hard. Yeah, it works till you blow your amp up. Get your self some unshielded speaker cable, I like Canare stuff, the 4S-8 is good. Well hopefully your amp is not hurt too bad, sounds like you have not cranked it too hard. Cheers.

 

[Bob Lee (QSC)]

Originally posted by Droog
Because instrument cable is sheilded and increases ohm load to your amp in a huge way, makes it work way too hard.

Disregard that.

This is from thread http://www.talkbass.com/forum/showthread.php?s=&threadid=100896:

Any signals at instrument level (millivolts) or line level (around a volt, such as the preamp output feeding the power amp input) should be on shielded cable. Unshielded cable may allow more noise and hum in, particularly in settings where there is a lot of electrostatic noise to be picked up. Shielded cables have fairly small conductors, but that's fine because they are used in high-impedance circuits where the current flow is a couple milliamps at most.

Speaker-level signals (10's of volts; several amperes of current) must be carried on large-gauge unshielded cables, not shielded instrument cables. Using an instrument cable in place of a speaker cable is highly unlikely to damage anything, but it's unwise because the conductors are small (that's not good in a low-impedance, high-power circuit) and because the capacitance between the conductors is relatively high, which may cause some amps to become unstable, leading to oscillation. Nevertheless, neither a type of cable (unless it's shorted) nor a higher load impedance will make an amp work harder.

 

[Droog]

O.k. go use your instrument cable for speaker cable and when your amp thermals 20 minutes into a gig you will know where the problem is.

Sometimes experiance is the only way to learn, have fun

 

[Bob Lee (QSC)]

Originally posted by Droog
O.k. go use your instrument cable for speaker cable and when your amp thermals 20 minutes into a gig you will know where the problem is.

Instrument cables are not suitable for use as speaker cables, but they are not likely to make the amp thermal unless the capacitance between the inner conductor and the shield causes the amp to oscillate. If that happens, then overheating is not the real problem--the amp's stability is. Most amps are designed well enough that they won't go haywire because of a few hundred or thousand picofarads of capacitance (but it's still a good idea not to push the limit).

Nevertheless, low-impedance power circuits should have appropriately sized wire, and shielded instrument cable isn't it.