Follow It Home Posted March 16, 2008 Share Posted March 16, 2008 Hey Everyone what are the rules on what cabs I can plug my Valve Junior Head into. What does it mean by like "handles 100 watts"? Is that the head watts? if so wouldnt I be safe with just about anything since its only a 5 watt head? Thanks! Link to comment Share on other sites More sharing options...
TWANG Posted March 17, 2008 Share Posted March 17, 2008 Generally people like a speaker closer to the amps wattage.. for instance 25 watts. or 50 watts. * I use 50 watt* But it'll run 4X12 so.. no problem there at all. Sensitivity is what matters. 100db sensitivity is a good minimum. the higher the sensitivity, the louder the amp. mostly you want to be darn sure you're using the right ohms.. don't mismatch the ohmage at the output jack.. use the ohms speaker you plug into.. 4 for 4 8 for 8 and 16 for 16. multi speaker cabs can vary so .. if they don't say so on the package.. test! TWANG Link to comment Share on other sites More sharing options...
wpkg Posted March 17, 2008 Share Posted March 17, 2008 multi speaker cabs can vary so .. if they don't say so on the package.. test! TWANG How would we test the ohmage of a speaker? just put a meter across the terminals? Link to comment Share on other sites More sharing options...
ricach Posted March 17, 2008 Share Posted March 17, 2008 How would we test the ohmage of a speaker? just put a meter across the terminals? yes, but you won't get the exact reading. make sure your meter is calibrated to zero first. without going into the technical aspect of why (because i can't remember right now) - you need to round up to the next ohm rating (i.e. 2,4,8 or 16). For example if your meter reads 2.6, its actually 4 ohms. 5.1, will be 8 ohms. etc. Link to comment Share on other sites More sharing options...
tunghaichuan Posted March 17, 2008 Share Posted March 17, 2008 yes' date=' but you won't get the exact reading. make sure your meter is calibrated to zero first. without going into the technical aspect of why (because i can't remember right now) - you need to round up to the next ohm rating (i.e. 2,4,8 or 16). For example if your meter reads 2.6, its actually 4 ohms. 5.1, will be 8 ohms. etc.[/quote'] Just to clarify: when checking the speaker with a DMM you are measuring the DC resistance of the voice coil, not the impedance. The DC resistance is always a little lower than the nominal impedence. tung Link to comment Share on other sites More sharing options...
bluefoxicy Posted March 17, 2008 Share Posted March 17, 2008 tung's right. Impedance is from AC; when you change the voltage in a wire (conductor), it has its own capacitance, among other things. It also generates an electromagnetic field. Lots of other stuff going on here you can study in an EE class. One very interesting thing--besides capacitance and electromagnetism etc--is it also resists the flow of current not based purely on a nominal resistance of the material, but also on the AC frequency. We measure impedance as a complex curve, and list it as the root mean square average of that curve. Or something along those lines. If you wind a coil 6000 times you'll get some impedance; wind it 12000 times and you get a lot more, BUT not much more resistance (barely any, it's just a longer wire!). Link to comment Share on other sites More sharing options...
wedgeSG Posted March 18, 2008 Share Posted March 18, 2008 Just to refresh my memory, (gettin old sucks), From my VJ Head I'm going into a 2x12 cabinet wired in parallel for an 8ohm load. The speakers had two positivve and two negative terminals at each connection point so I duplicated the parallel setup on the extra terminals and ran these to a second 1/4" jack. This gave me sort of a bi-directional in & out. The 12's are 16 ohm - 2, 16ohms in parallel = 8ohm cabinet. This runs into another cab with a single 8ohm 10" speaker. Am I right that an 8ohm cab plugged into a second 8ohm cab would be plugged initially into the 4ohm jack on the VJ head. i.e. VJH 4ohm jack out to 1st jack of 8ohm 2x12 out the other parallel wired terminals of 2x12 into single 10" - 8ohm cab. 8ohm cab + 8ohm cab = plug into 4ohm jack Right? Wedgie Link to comment Share on other sites More sharing options...
cGil Posted March 18, 2008 Share Posted March 18, 2008 Better you should just check it on this... It'll help clear things up and remove all doubt (that you're right). http://www.1728.com/resistrs.htm And for those like myself who're still recovering from Saturday night, this may help some, too. http://www.tonetubby.com/spkwire.htm Gil... Link to comment Share on other sites More sharing options...
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