Members petejt Posted February 12, 2010 Members Share Posted February 12, 2010 The MarkIV has three speaker outputs- one 8 ohm mono output, and two 4 ohm outputs, wired in parallel. I believe that means that each "4 ohm" socket connects to an 8 ohm load (cab). My Stiletto cab appears to have the same type of speaker inputs- one 8 ohm, and two "4 ohm" inputs. Does this mean that each input socket is actually an 8 ohm load? I guess I am saying, is the cab theoretically a pair of 8 ohm 2x12 cabs in one enclosure? Can I connect the 4 ohm outputs of the MarkIV to the 4 ohm inputs of the cab, safely? I don't want to bust my amp................. Link to comment Share on other sites More sharing options...
Members LordThurisaz Posted February 12, 2010 Members Share Posted February 12, 2010 I believe you are right, but to be sure you could call Mesa. Link to comment Share on other sites More sharing options...
Members newholland Posted February 12, 2010 Members Share Posted February 12, 2010 do you have a multimeter? if so- just plug your speaker cable into the speaker jack, and measure the resistance from tip to ring. if it comes back around 2.8 ohms-- then it's ACTUALLY a 4 ohm input (no doubt- two 8 ohm speakers in parallel).. which would be bad for your amp. if it comes back 6.8 on the 4 ohm tap-- then your speculation's probably right. i'd think you're probably right about the 'pair of 8 ohm 212s in the same cabinet'-- but your BEST bet is to actually measure it- or call mesa. but i'd think measurement's your safest bet. mesa does like their 8 ohm cabinets.. Link to comment Share on other sites More sharing options...
Members Sixtonoize Posted February 12, 2010 Members Share Posted February 12, 2010 If the cab's inputs are marked are 8, 4, and 4, that means that you'll be giving your amp a 2 ohm load if you plug into both of the 4 ohm inputs on the cab. According to what you've posted, the cab is loaded with 8 ohm speakers and wired as two parallel pairs (4 ohm each). When you plug into the Mono input, the two pairs are in series (4 + 4 = 8). If you're not using the Mono input, the two stereo pairs are disconnected, so your amp will be seeing a parallel pair of 4 ohm loads (4 || 4 = 2). Link to comment Share on other sites More sharing options...
Members petejt Posted February 12, 2010 Author Members Share Posted February 12, 2010 do you have a multimeter?if so- just plug your speaker cable into the speaker jack, and measure the resistance from tip to ring. if it comes back around 2.8 ohms-- then it's ACTUALLY a 4 ohm input (no doubt- two 8 ohm speakers in parallel).. which would be bad for your amp. if it comes back 6.8 on the 4 ohm tap-- then your speculation's probably right.i'd think you're probably right about the 'pair of 8 ohm 212s in the same cabinet'-- but your BEST bet is to actually measure it- or call mesa. but i'd think measurement's your safest bet.mesa does like their 8 ohm cabinets.. There's a multimeter in the house but I think it's busted, so unfortunately I cannot measure it. I'll try get it working and then measure. This situation is more complicated, because I want to use the cab as if it's two individual "2x12" cabs that are 8 ohms each. It's necessary because I want to use another 4x12 as a 'pair of 2x12 cabs' where each 'half' is an 8 ohm load. Link to comment Share on other sites More sharing options...
Members petejt Posted February 12, 2010 Author Members Share Posted February 12, 2010 If the cab's inputs are marked are 8, 4, and 4, that means that you'll be giving your amp a 2 ohm load if you plug into both of the 4 ohm inputs on the cab.According to what you've posted, the cab is loaded with 8 ohm speakers and wired as two parallel pairs (4 ohm each). When you plug into the Mono input, the two pairs are in series (4 + 4 = 8). If you're not using the Mono input, the two stereo pairs are disconnected, so your amp will be seeing a parallel pair of 4 ohm loads (4 || 4 = 2). Well, the sockets on the cab match what's on the amp. They both have a single 8 ohm socket, and two sockets each marked as "4 ohms". So I guess that means for the amp, it either sends out one signal at 8 ohms, or two signals each at 8 ohms. And for the cab, wouldn't it be that it either accepts one signal at 8 ohms, or two signals each rated at 8 ohms? I guess not? Going by what you said? Link to comment Share on other sites More sharing options...
Members yourguitarhero Posted February 12, 2010 Members Share Posted February 12, 2010 RTFM Link to comment Share on other sites More sharing options...
Members JimAnsell Posted February 12, 2010 Members Share Posted February 12, 2010 RTFM is that gear geek board speak for read the {censored}ing manual? Link to comment Share on other sites More sharing options...
Members Cougar Hunter Posted February 12, 2010 Members Share Posted February 12, 2010 in order to use BOTH 4ohm jacks, you need to plug an 8 ohm load into each jack. if you use one 4ohm jack, you plug one 4ohm load into it. That's all you need to know. Link to comment Share on other sites More sharing options...
Members petejt Posted February 12, 2010 Author Members Share Posted February 12, 2010 If the cab's inputs are marked are 8, 4, and 4, that means that you'll be giving your amp a 2 ohm load if you plug into both of the 4 ohm inputs on the cab. According to what you've posted, the cab is loaded with 8 ohm speakers and wired as two parallel pairs (4 ohm each). When you plug into the Mono input, the two pairs are in series (4 + 4 = 8). If you're not using the Mono input, the two stereo pairs are disconnected, so your amp will be seeing a parallel pair of 4 ohm loads (4 || 4 = 2). I guess you may be right.You see, my other cab would be loaded with 16 ohm speakers. Each pair is wired in parallel, so it's 8 ohms per side. Then for mono the pairs are connected to each other in series, adding the impedance to 16 ohms.Damn this sucks, I don't know what to do with this Stiletto cab.What's also hard is that with the other cab, I want to wire it all up with 8 ohm speakers too. So now I guess it will be a hellbasket too Link to comment Share on other sites More sharing options...
Members yourguitarhero Posted February 12, 2010 Members Share Posted February 12, 2010 is that gear geek board speak for read the {censored}ing manual? Yes, not specifically just for gear boards, but a useful acronym in many contexts. The Mesa manuals explain this all pretty well. You can read them on their site as PDFs. Link to comment Share on other sites More sharing options...
Members petejt Posted February 12, 2010 Author Members Share Posted February 12, 2010 in order to use BOTH 4ohm jacks, you need to plug an 8 ohm load into each jack. Well I hope so. Each pair of speakers will hopefully be an 8 ohm load. If it is, then all is well. Link to comment Share on other sites More sharing options...
Members fly_with_v Posted February 12, 2010 Members Share Posted February 12, 2010 in order to use BOTH 4ohm jacks, you need to plug an 8 ohm load into each jack.if you use one 4ohm jack, you plug one 4ohm load into it.That's all you need to know. This is correct. Download the manual from the Mesa site, it will say the exact same thing and show you all the other options. Link to comment Share on other sites More sharing options...
Members Sixtonoize Posted February 12, 2010 Members Share Posted February 12, 2010 Well I hope so. Each pair of speakers will hopefully be an 8 ohm load. If it is, then all is well. It's not, for the reasons I previously explained. Link to comment Share on other sites More sharing options...
Members mikey383 Posted February 12, 2010 Members Share Posted February 12, 2010 Why do you want to run your 4x12 as two 2x12s through a mono amp? It will not make any difference in the sound. Link to comment Share on other sites More sharing options...
Members MattACaster Posted February 12, 2010 Members Share Posted February 12, 2010 Well I hope so. Each pair of speakers will hopefully be an 8 ohm load. If it is, then all is well. It is.The 2 4ohm jacks are meant to be used at 4 ohms total either across one or both jacks. So either 1 4ohm cab or 2 8ohm cabs. Link to comment Share on other sites More sharing options...
Members Giga Posted February 12, 2010 Members Share Posted February 12, 2010 From your initial post I'd say your cab has four 8 ohm speakers in it, wired in parallel pairs (hence the two 4 ohm inputs). Using the single 8 ohm input puts the pairs in series. So: Use the 8 ohm output of the amp into the 8 ohm cab-input and you're done. Giga Link to comment Share on other sites More sharing options...
Members jlb32 Posted February 12, 2010 Members Share Posted February 12, 2010 in order to use BOTH 4ohm jacks, you need to plug an 8 ohm load into each jack. if you use one 4ohm jack, you plug one 4ohm load into it. That's all you need to know. The MAIN reason for the two 4ohm jacks is so you can run two 8ohm cabs in parallel together (remember all Mesa cabs are wired to 8ohms). You can use just one of the 4ohm jacks but you need a 4ohm cab to do so. Link to comment Share on other sites More sharing options...
Members petejt Posted February 13, 2010 Author Members Share Posted February 13, 2010 Why do you want to run your 4x12 as two 2x12s through a mono amp? It will not make any difference in the sound.It's complicated.... I want to run two 4x12 cabs as if they are four 2x12 cabs. I'm doing a wet/dry/wet thing where a stereo poweramp will run the outer two 2x12 speaker pairs, and the MarkIV will run the inner two 2x12 speaker pairs.Plus I get a mix of different speakers to get different blends of sound, no matter how marginally different they would be. Link to comment Share on other sites More sharing options...
Members petejt Posted February 13, 2010 Author Members Share Posted February 13, 2010 It is. The 2 4ohm jacks are meant to be used at 4 ohms total either across one or both jacks. So either 1 4ohm cab or 2 8ohm cabs. Great! Link to comment Share on other sites More sharing options...
Members petejt Posted February 13, 2010 Author Members Share Posted February 13, 2010 The MAIN reason for the two 4ohm jacks is so you can run two 8ohm cabs in parallel together (remember all Mesa cabs are wired to 8ohms). You can use just one of the 4ohm jacks but you need a 4ohm cab to do so. Cool, thanks for that. Link to comment Share on other sites More sharing options...
Members guitarbilly74 Posted February 13, 2010 Members Share Posted February 13, 2010 in order to use BOTH 4ohm jacks, you need to plug an 8 ohm load into each jack.if you use one 4ohm jack, you plug one 4ohm load into it.That's all you need to know. correct Link to comment Share on other sites More sharing options...
Members petejt Posted February 13, 2010 Author Members Share Posted February 13, 2010 I got it all working now, works fine. {censored} that it's more than fine! The cab has gone so well that I've swapped them over! Now I'm running the MarkIV into the 'new' cab, which has two EV 12S 200 watters in the bottom, a CL90 Black Shadow on the right top side, and a Vintage 30 on the left top side. It's wired in stereo, 16 ohms per side. Now before you say "clips or GTFO", I'll run off and hopefully get some clips up. Link to comment Share on other sites More sharing options...
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