kingforaday Posted February 2, 2011 Share Posted February 2, 2011 ok i've searched through all the various information on here and i think i'm just confusing myself even more! basically ever since i started using my 1st amp & cab setup (hartke 3500 head and an 8 ohm vx410 cab) i've linked them based on the information in the manual for that cab. when i bought another cab i linked the 1st from an output on the amp and the 2nd from the 'extension' output on that cab so the cabs would be linked in parallel and the impedance would be 4 ohms (as it said in the manual) so two 8 ohm cabs linked in parallel via the extension socket there is 4 ohm impedance but if i take two 8 ohm outputs from the back of my amp thats series (?) and it says for cabs wired in series, the impedance is the 'sum of the speakers individual impedance' the other day i bought a new head and started looking for cabs but noticed not many had 'extension' sockets on the back so that got me thinking maybe i don't understand this afterall! [b]so once and for all, if i link everything up in series and use the two 8ohm outputs from the head and go into two 8ohm cabs is the impedance reduced to 4ohm well? [/b] if so why does the manual for the cab say to link in parallel to achieve this and completely glosses over the series linkup option?! confused. Quote Link to comment Share on other sites More sharing options...
alexclaber Posted February 2, 2011 Share Posted February 2, 2011 [quote name='kingforaday' post='1112147' date='Feb 2 2011, 11:15 AM']ok i've searched through all the various information on here and i think i'm just confusing myself even more! basically ever since i started using my 1st amp & cab setup (hartke 3500 head and an 8 ohm vx410 cab) i've linked them based on the information in the manual for that cab. when i bought another cab i linked the 1st from an output on the amp and the 2nd from the 'extension' output on that cab so the cabs would be linked in parallel and the impedance would be 4 ohms (as it said in the manual)[/quote] Correct! [quote name='kingforaday' post='1112147' date='Feb 2 2011, 11:15 AM']so two 8 ohm cabs linked in parallel via the extension socket there is 4 ohm impedance but if i take two 8 ohm outputs from the back of my amp thats series (?) and it says for cabs wired in series, the impedance is the 'sum of the speakers individual impedance'[/quote] Two 8 ohm outputs from your amp will be parallel, not series. So the cabs are still in parallel, two 8 ohm nominal cabs resulting in 4 ohms nominal. [quote name='kingforaday' post='1112147' date='Feb 2 2011, 11:15 AM']the other day i bought a new head and started looking for cabs but noticed not many had 'extension' sockets on the back so that got me thinking maybe i don't understand this afterall! [b]so once and for all, if i link everything up in series and use the two 8ohm outputs from the head and go into two 8ohm cabs is the impedance reduced to 4ohm well? [/b] if so why does the manual for the cab say to link in parallel to achieve this and completely glosses over the series linkup option?! confused.[/quote] You wouldn't be linking the cabs in series, they'd be in parallel, that's why. In summary - the two (or more) outputs on the back of an amp are in parallel (unless its a valve amp with various impedance taps or a 'stereo' amp like a handful of bass amps and all PA power amps, i.e. two amps in one box). The two (or more) inputs on the back of a cab are in parallel. Any of them can be used as inputs or outputs, so you can daisy-chain cabs (again, parallel wiring). There is only one situation where a standard product and standard lead will result in a SERIES connection - that is with the handful of combos on the market that are stable down to 4 ohms, contain a 4 ohm nominal internal speaker and have an extension cab output. This output should be labelled as a series output and it allows you to connect a second 4 ohm cab, for total nominal impedance of 8 ohms. (The extension cab should really be identical to the combo's enclosure because of the issues with series wiring). The only example I can think of with this is some of the older Nemesis combos and possibly some H&Ks, though I'm sure there are more. However it's not at all common. Some combos give you the choice of a 4 or 8 ohm speaker, like the Walkabout - in that case you're not meant to connect an extension cab to the 4 ohm version but because Mesa build rather nice 'overspecced' amps you can get away with running it below 4 ohms nominal. With all heads and cabs, unless you specially make up unusual leads, all the wiring is parallel, all the time. Quote Link to comment Share on other sites More sharing options...
kingforaday Posted February 2, 2011 Author Share Posted February 2, 2011 ahhhh so the extension socket thing is just a feature so you can hook everything up without having to get longer speaker leads or something? thanks for your help! Quote Link to comment Share on other sites More sharing options...
alexclaber Posted February 2, 2011 Share Posted February 2, 2011 [quote name='kingforaday' post='1112169' date='Feb 2 2011, 11:43 AM']ahhhh so the extension socket thing is just a feature so you can hook everything up without having to get longer speaker leads or something? thanks for your help![/quote] Yes, or for when your amp hasn't got enough outputs to connect all the cabs directly. Quote Link to comment Share on other sites More sharing options...
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