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Instrument cables vs. speaker cables

Discussion in 'Miscellaneous [BG]' started by ikickuintheballs, May 17, 2001.


  1. Is there much of a difference between the two? I use a regular instrument cable for my head to cab. Should I be using a speaker cable? Does this affect the sound?
     
  2. I'd be using a proper speaker cable. Other's here are more qualified to tell you why, but the two things that come to mind are the impedance (capacitance??) of the cable being different, which can adversely affect tone. The other thing is the amount of juice running through that cable. instrument cables are probably not designed to handle the power going though a cable from an amp to a cab.

    FF
     
  3. rickbass

    rickbass Supporting Member

    I'lltry not to be too redundant of Fretless.

    Basically, the speaker cable produces more noise and a weaker signal.

    Speaker cable isn't noise-shielded nor is the shielding it has grounded and it likes a higher current than an instrument can provide.

    Not a good idea to use instrument cable to connect your head and cab. Instrument cable has more internal capacitance and it kills your highs. Instrument cable can't handle the higher voltages that speaker cable can. If it gets too hot, melts, and causes a short circuit, WHAMMO!!...goodbye output transistors/transformer!
     
  4. Eep. This may be the cause of my speaker probs. I'll be picking up 2 (1 for use and 1 for backup) ASAP! Thanks guys!
     
  5. jasonbraatz

    jasonbraatz

    Oct 18, 2000
    Oakland, CA
    real men use speakons.


    jason
     
  6. I beg to differ from Rickbass1 in some respects.

    I'm not sure that speaker cable producing more noise and a weaker signal is quite correct.

    In the context of feeding a cab from a head, ANY noise produced by ANY type of cable will be totally and completely swamped by the output from the head. The noise picked up by the bass pups, that generated by the head etc, will always be far greater than any contribution made by the cable.

    The capacitance of signal cable, too, will have little or no effect on the highs from the bass at the impedances involved (head o/p impedance and cab i/p impedance). At radio frequencies it will become significant but not at bass guitar frequencies, IMHO.

    But I agree with Rickbass 1 that it's not a good idea to use instrument cable for the head - cab link. In fact I will go further than that and say outright THAT YOU SHOULD NEVER EVER DO IT.

    Signal cables are made to handle the low signal levels from bass to head. Speaker cables are made to handle the high currents that the head produces to drive the cab (sorry again, Rickbass1, but it's current that matters rather than the voltage). High currents can lead to heating effects in the cable which, if they become significant for whatever reason, can lead to the cable burning out and the very strong possibility of damage to the head.

    My advice, in short, is to stick to using the cables for their correct purpose.

    Best regards

    Rockin John
     
  7. rickbass

    rickbass Supporting Member

    Rockin' - Not that they're undoubtedly correct, but my info came from the August, 96, issue of Guitar Player in their "Toy Box"....just so you know my info wasn't my "opinions."
     
  8. Hi Rickbass1.

    No, good friend, not wishing to have a pop at you. Naturally, I didn't know you were quoting from a book. I'm not the worlds electronics expert by a long way but some of those statements do seem a touch - well - odd.

    I guess part of the difficulty faced by such publications is getting non-techie people to grasp a techie subject. Very ofter over-simplifications are made to that end and the whole picture become distorted beyond what is reasonable. That's how it comes over to me sometimes, anyway.

    Hope you took no offence from my comments because, very certainly, none was intended.

    Regards.

    John
     
  9. rickbass

    rickbass Supporting Member

    John- None taken, whatsoever. Besides, one better have some thick skin to get on these boards.

    I just wanted you all to know that when it comes to tech stuff, I consider reliance on memory a disservice to the original person who asked, unless you're someone who has dealt with this stuff on a professional level. I never made a cable and what I know is what I read and I try to discern the bull from the truth.
     
  10. MikeyD

    MikeyD

    Sep 9, 2000
    Probably the biggest differences between them are as follows:

    Speaker cables:
    _ lower gauge (much thicker) copper wire
    _ unshielded

    Instrument cables:
    _ higher gauge (thinner) wire
    _ shielded

    What this means is that the unshielded speaker cables, if used in a very low *voltage* application, will be susceptible to picking up the low voltages induced or coupled into them from RFI (radio frequency interference) or EMI (electromagnetic interference). As far as I'm concerned, RFI is a subset of EMI. Anyway, the low "noise" voltages typical of EMI are significant compared to the low signal voltages of instruments - particularly high impedance passive pickups. The shielding in instrument cables effectively grounds out external signals that are coupled in (wires act like antennas, but the shield blocks the waves from reaching the signal conductors). This is why speaker cables will tend to be noisier than instrument cables.

    Now, since instrument cables are not designed to handle high currents, they have relatively tiny wire gauges. This saves money and makes them more flexible and lighter. If you use an instrument cable to carry high power from an amplifier to a speaker, the resulting current could cause excessive heating of the cable and might burn it out (or start a fire in some cases). Even if not, the effective resistance of an instrument cable can be significant compared to the speaker resistance and could adversely affect the sound (lower the efficiency and damping factor). Therefore - use speaker cables for speakers and instrument cables for instruments!

    - Mike
     
  11. Yeh.

    If you use non-shielded cable [such as head to cab cables] to connect the bass to the cab, you will get noise. LOADS OF IT..... (The cable doesn't cause - manufacture - the noise).

    If you use an instrument cable to connect the head to the cab you'll probably burn it out, at the very least, wrecking the cable.

    John
     
  12. Paul A

    Paul A

    Dec 13, 1999
    Hertfordshire U.K!
    Hi,
    Here's a horror story for you!
    I spent MONTHS restoring a Vintage Vox AC30 for a
    friend.
    First day he had it back he pugged in an extension cab to it with one of those horrible cheap curly guitar leads.
    After about five minutes....BLAM!!
    There was so much damage (transformers,caps), even to those precious blue Bulldog speakers it was hardly worth repairing.
    Anyway, it got repaired but it's never quite sounded right since!
     
  13. Boplicity

    Boplicity Supporting Member

    To reinforce what MikeyD so convincingly has written in his authoritative post, I'll quote directly from "Sound Check: The Basics of Sound and Sound Systems," by Tony Moscal; Hal Leonard Publications.

    Page 62: "Impedance and Cables."
    Cable and wire by themselves add resistance and can also effect signal. In particular cable lengths of roughly 15 feet or more do a better job of transmitting some frequency ranges than others. This is due to an electrical property called capacitance. Long wire carrying high impedance signals tend to lose or "roll off" high frequencies making voice reproduction dull and unintelligible.

    Long wire carrying low impedance signals also roll off high frequencies, but only those well above audible range. Therefore whenever long cables are required, low impedance sources should be used.

    Speaker cable (unshieded) also adds resistance and if long speaker cables are used, some of the power will actually be lost in the cable. Using larger wire and shorter speaker cable length will dramatically improve power amp/speaker performance. In order to accomplish this:

    1. Keep power amps close to speaker.
    2. Use heavy guage speaker cables. The smaller the number, the thicker the wire; #14 is bigger than #20.
    3. Use unshielded speaker cable for speaker connections.

    ---------------------------------------------
    A wise salesman at a music store once explained to me how immportant it is to use speaker cable for speakers and never guitar cable. I have had, however, great difficulty convincing guitar players in bands I have played in that this is true. They have been openly skeptical of my claims and say it is just a scheme to get people to buy two kinds of cable. Go figure.
     
  14. Boplicity

    Boplicity Supporting Member

    While we are on this topic, I'll quote further from the same book and author above. This infor is so useful, I'd like to share it.

    "Some Tips on Reducing Noise Include:"

    1. Keep cable short. Running short cables reduces the area in the ground loop.
    2. Keep cables of the same type together. Run AC cords, line level cords, low level cords in separate groups. This eliminates loops.
    3. Keep cables of differenttypes away from each other. Keep power cords away from microphone cables, line level cables away from speaker wire, etc. If you have to cross different types of cable, corss them at 90 degrees. That will reduce hum entering the system.
    4. Rack mount your equipment. The metal rails of the rack ground the chassis together as well as keep the units close allowing the use of shorter cables.
    5. Use proper cables. Using a shielded cable for a speaker can degrade the sound quality and performance of the power amp. ALways use shielded cables for low and line level signal and use unshileded cable for high levels signals. Remember,a faulty cable is the number one source of unwanted noise.
    6. Be sure to match signal levels. Hiss can occur in a system if the output of one devoice is too weak for the input of another. Know the output and input capabilities of the equipment used.

    (From "Sound Check: The Basics of Sound and Sound Systems" by Tony Moscal. Hal Leonard Publications. $14.95)