Samlowe Posted January 20, 2012 Share Posted January 20, 2012 I have recently been playing with my cab set up and have come across a two cab configuration i'm really happy with sound wise. But here is the problem, the first cab is a marshall DBS 2x15 rated 600w at 4 ohm and the other a marshall 4x12 guitar cab, 140w at 8 ohm. The amp is a marshall JCM 800 bass series. ( completely unintended marshall worship! ) The over all resistance of the cabs is 2.66 ohm if my maths is correct but my head will only switch to 4 ohm minimum. Having done a little research prior to hooking everything up I have come to the conclusion that with all valve amps (pre and power) as long as i don't go below 2 ohm this shouldn't cause any major issues other than valves running hotter than usual and needing replacing sooner... which i can live with. What do you think? Cheers. Quote Link to comment Share on other sites More sharing options...
icastle Posted January 20, 2012 Share Posted January 20, 2012 Valve amps have a reputation for being more impedance tolerant but I think you're asking for trouble if you exceed the manufacturers specification to the degree you're considering. Do you have any idea what impedance the individual speakers are? There might be a way of rewiring it to get it closer to 8Ω. Quote Link to comment Share on other sites More sharing options...
deepbass5 Posted January 20, 2012 Share Posted January 20, 2012 (edited) Can't help saying why a 2 x 15" and a 4 x 12" ? Having said that is the amp 100Watt? You could use[size=1] [size=4][b]Kirchhoff's [/b][b]Current[/b][b]Law[/b][/size][/size][size=4].[/size] The 2 x15 will be two 8ohms in parallel = 4ohms and the 4 x 12" will be 8 ohm speakers in a series- parallel configuration. It’s all maths after that, Without putting pen to paper it looks like you may get away with it. as the higher wattage speakers are the two 8ohms in the 15 cab, but check how the 4 x12 is wired to be safe. I assume four 8 ohm speakers two in series parallel to another two in series. 8+8=16 8+8=16 in parallel = 16/2 = 8 ohm Edited January 21, 2012 by deepbass5 Quote Link to comment Share on other sites More sharing options...
Blademan_98 Posted January 20, 2012 Share Posted January 20, 2012 +1 on rewiring the 4x12 Quote Link to comment Share on other sites More sharing options...
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