Members Thelonius Posted June 20, 2005 Members Share Posted June 20, 2005 I get confused. 16 down to 8 or 4 into two eights, etc. I'm replacing the speakers in my 2x12 combo. Right now they are 8 ohm speakers in there. So I assume I just replace them with 2 more 8 ohm speakers right? Then I'm going to get an empty 2x12 cab and put the speakers that I pulled out from the combo into that. Those speakers are 8 ohm, so what ohm rating does my cabinet need to have? Do different resistance levels sound different or something? Link to comment Share on other sites More sharing options...
Members Teahead Posted June 20, 2005 Members Share Posted June 20, 2005 iirc, two 8 ohms can be wired to see 16 & 4... I think! Link to comment Share on other sites More sharing options...
Members jonny guitar Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by Thelonius I get confused. 16 down to 8 or 4 into two eights, etc. I'm replacing the speakers in my 2x12 combo. Right now they are 8 ohm speakers in there. So I assume I just replace them with 2 more 8 ohm speakers right? speakers can be wired in parallel or series...parallel will half the impedance and series with double it ie. using 2 x 8 oms would be series 16 and par. 4. So if you have 2 x 8 in par. right now you have 4 ohm's so the easiest replacement is 2 more 8s. edit: parallel are better to run than series because if you blow a speaker in series you can damage you OT more easily than parallel wired speakers because the series circuit will be interupted and the OT will have no load. Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 You MUST match the impedance load to what the amplifier needs to have for a proper load. You can fry tubes, transformers etc if you mis-match the load. If you are replacing 8 ohm speakers, stick with 8 ohm speakers and wire them EXACTLY as they are now. To double check, put a meter on the 2 leads BEFORE you hook them back up to the amp. You should get roughly the same as is marked on the back of the amp. If you read between 7.3 to 8.5 ohms them you're good to go. If you are trying to make a 2x12 extention cabinet for the same amp, I would get 2 8 ohm speakers and wire them in the same pattern as is inside the combo, and chek the ohms again before hooking up. The amp should be labelled on the Ext. Spkr jack exactly what ohms it should be. And +1 on the paralell or series answers. You can make lots of different combos of ohms, but it's important that you match the amplifiers output load. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted June 20, 2005 Members Share Posted June 20, 2005 you sound completely and utterly confused... if you are wanting to just switch the speakers in your amp for ones wired exactly the same for the same impedance (so you can use it exactly the same as before) you would want to replace the speakers for one with the same rating i will go try and make some pictures to try and explain series/parrallel and how you would add them up David Link to comment Share on other sites More sharing options...
Members jonny guitar Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by yaz75 You MUST match the impedance load to what the amplifier needs to have for a proper load. You can run 2-1 mismatch with pretty much no problems as long as you are going higher impedance draw...never go lower. Link to comment Share on other sites More sharing options...
Members RoboPimp Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by jonny guitar You can run 2-1 mismatch with pretty much no problems as long as you are going higher impedance draw...never go lower. unless it's a tube amp Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by jonny guitar You can run 2-1 mismatch with pretty much no problems as long as you are going higher impedance draw...never go lower. Possibly you are correct. I've had mis-matches that made an amp die a spectacular death. I'm REAL careful now as I've had to make some pretty spendy repairs in my 'learning curve' of equipment ownership! I guess after I've spent that much on my amps, I don't want to get cute with the load and ruin them. I'm not saying it can't be done, just that I'm REAL gun shy after a few horrific events! Link to comment Share on other sites More sharing options...
Members Thelonius Posted June 20, 2005 Author Members Share Posted June 20, 2005 Originally posted by yaz75 You MUST match the impedance load to what the amplifier needs to have for a proper load. You can fry tubes, transformers etc if you mis-match the load. If you are replacing 8 ohm speakers, stick with 8 ohm speakers and wire them EXACTLY as they are now. To double check, put a meter on the 2 leads BEFORE you hook them back up to the amp. You should get roughly the same as is marked on the back of the amp. If you read between 7.3 to 8.5 ohms them you're good to go. If you are trying to make a 2x12 extention cabinet for the same amp, I would get 2 8 ohm speakers and wire them in the same pattern as is inside the combo, and chek the ohms again before hooking up. The amp should be labelled on the Ext. Spkr jack exactly what ohms it should be.And +1 on the paralell or series answers. You can make lots of different combos of ohms, but it's important that you match the amplifiers output load. Oh...good point I hadn't thought to mention that. The seperate cab is not going to be used with the combo. It will be used with a head. I don't have the head yet so I don't know what the ohms rating is. Although as far as blowing speakers I tend to use rather efficient speakers for the amp's rating. Link to comment Share on other sites More sharing options...
Members sstim8or Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by yaz75 Possibly you are correct. I've had mis-matches that made an amp die a spectacular death. I'm REAL careful now as I've had to make some pretty spendy repairs in my 'learning curve' of equipment ownership! I guess after I've spent that much on my amps, I don't want to get cute with the load and ruin them.I'm not saying it can't be done, just that I'm REAL gun shy after a few horrific events! I plugged my amp ouput into my pedalboard once. I almost had a heart attack when I realized what I'd done. Nothing was damaged, amazingly. Hey, you gonna be able to make in on Saturday? Link to comment Share on other sites More sharing options...
Members jonny guitar Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by RoboPimp unless it's a tube amp No, you can do it with a tube amp as well. Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by sstim8or I plugged my amp ouput into my pedalboard once. I almost had a heart attack when I realized what I'd done. Nothing was damaged, amazingly. Hey, you gonna be able to make in on Saturday? I'm not sure I'm up for being publicly stoned to death this saturday. I think pontius has a bounty out on my head! I had my Peavey Classic 50 410 re-tubed and new speakers all ready to go, but I don't think I can make it. Plus I'm not sure you need a hack player like myself making all kinds of noise there anyways! Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by Thelonius Oh...good point I hadn't thought to mention that. The seperate cab is not going to be used with the combo. It will be used with a head. I don't have the head yet so I don't know what the ohms rating is. Although as far as blowing speakers I tend to use rather efficient speakers for the amp's rating. What head are you getting? Link to comment Share on other sites More sharing options...
Members hbar Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by yaz75 What head are you getting? Once or twice a week. Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by hbar Once or twice a week. *rim shot* Link to comment Share on other sites More sharing options...
Members hbar Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by yaz75 *rim shot* Thank you, thank you. I'll be here all week. Don't forget to tip your waitress. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted June 20, 2005 Members Share Posted June 20, 2005 see attached picture for series, the impedances add up, so for 2 8 ohm speakers, 8 + 8 = 16 ohms total for series the formula is 1/speaker1 + 1/speaker2 = 1/totalin real life, for 2 8 ohm speakers wired in parallel, the value of the speakers (assuming they are the same) is halved, so 8//8 = 4 ohms total amps dont like different impedances, at best they can lower the power you will get from the amp, at worst, blow the output transformer (which can take out half the output section with it) i know my amps outputs are wired in parallel, so i have to use the paralell rule to work out the total impedance, so if i wanted to add a cab with the 16 ohm internal speaker, i would want a 16 ohm cab, so both together add up to 8 ohms total, which i set my amp to when you replace the speakers in your amp, use the same value of speakers, and make sure you wire them correctly (either in series or parallel) David Link to comment Share on other sites More sharing options...
Members BandofThievesâ„¢ Posted June 20, 2005 Members Share Posted June 20, 2005 Cut To the Chase Link to comment Share on other sites More sharing options...
Members Thelonius Posted June 20, 2005 Author Members Share Posted June 20, 2005 Originally posted by yaz75 What head are you getting? kt45 Link to comment Share on other sites More sharing options...
Members Thelonius Posted June 20, 2005 Author Members Share Posted June 20, 2005 Originally posted by BandofThieves Link to comment Share on other sites More sharing options...
Members BandofThievesâ„¢ Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by Thelonius * bows* I really appreciate all the help from everyone and how much you guys overestimate my knowledge on such matters, but I was about to ask someone to put some legos together and take a picture with little signs on them. If you run across any JBL's D,E,K series keep in mind the Black is positive and Red is Negative..UNLESS They have been reconed and the person chose to swap the leads which is stupid..I bought a many fender amps with jbls that the people thought sounded like {censored}e because they had rewired the amps out of phase:D Good luck with your project.. Link to comment Share on other sites More sharing options...
Members Narcosynthesis Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by BandofThieves Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by Thelonius kt45 VERY nice. I'm pretty sure it's 8ohms, but I've sure been wrong before. Good luck and I'd LOVE to hear it. Link to comment Share on other sites More sharing options...
Members BandofThievesâ„¢ Posted June 20, 2005 Members Share Posted June 20, 2005 Originally posted by Narcosynthesis that sounds pretty stupid going against the normal convention of red is positive, black negative...and i wish i had known about the tonetubby link before i made pictures and wrote the post (twice since the icture was too big the first tmie so it wiped everythign and i had to resize it and start again)David It's not really stupid when you consider the fact that in electrial codes Black Is the Juice..Jbl has some wiring diagrams that show mixmatched speakers as well,like an 8+8+4+16 etc..Pretty wild stuff..I think your post was great... Link to comment Share on other sites More sharing options...
Members yaz75 Posted June 20, 2005 Members Share Posted June 20, 2005 Yeah PLEASE don't work on your house wiring with the thought that "red/white is positive and black is negative.' I don't want you injured. It's bizarre that in DC, black is neg., and in AC black is the hot wire. Link to comment Share on other sites More sharing options...
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