jonnpip Posted July 29, 2013 Share Posted July 29, 2013 so i should know this by now the years ive been on bass but,if my genz benz 9.2 amp is 4 ohms and my berg cab is 4 too, is it not safe to hook a 2x12 4 ohms cab to the other output on the amp ? or does this reduce this to 2 ohms...advice please ? Quote Link to comment Share on other sites More sharing options...
andydye Posted July 29, 2013 Share Posted July 29, 2013 [quote name='jonnpip' timestamp='1375134904' post='2157221'] so i should know this by now the years ive been on bass but,if my genz benz 9.2 amp is 4 ohms and my berg cab is 4 too, is it not safe to hook a 2x12 4 ohms cab to the other output on the amp ? or does this reduce this to 2 ohms...advice please ? [/quote] Amp at 4 ohms = 1 4ohm cab or 2 x 8ohm cabs or 4 x 16ohm cabs Quote Link to comment Share on other sites More sharing options...
casapete Posted July 29, 2013 Share Posted July 29, 2013 Your amp will run a single 4 ohm cab or two 8 ohm cabs, but connecting two 4 ohms cabs (as you predict) will bring the load down to 2 ohms which your amp won't be happy with. Quote Link to comment Share on other sites More sharing options...
Judo Chop Posted July 29, 2013 Share Posted July 29, 2013 [quote name='andydye' timestamp='1375135018' post='2157223'] Amp at 4 ohms = 1 4ohm cab or 2 x 8ohm cabs or 4 x 16ohm cabs [/quote] Something like this should be stickied, I spent ages trying to figure out what I needed until someone on here explained it as simply as this. Really helpful if you haven't got a clue like me Quote Link to comment Share on other sites More sharing options...
jonnpip Posted July 29, 2013 Author Share Posted July 29, 2013 Cheers for reply, seems its a no then, drat ! Quote Link to comment Share on other sites More sharing options...
jonnpip Posted July 29, 2013 Author Share Posted July 29, 2013 deffo jack ! Quote Link to comment Share on other sites More sharing options...
icastle Posted July 29, 2013 Share Posted July 29, 2013 This is a nice little tool to keep in your Favourites. http://ampservice.de/impcalc.php?lang=e Quote Link to comment Share on other sites More sharing options...
AussieBassman Posted July 29, 2013 Share Posted July 29, 2013 (edited) [quote name='andydye' timestamp='1375135018' post='2157223'] Amp at 4 ohms = 1 4ohm cab or 2 x 8ohm cabs or 4 x 16ohm cabs [/quote] This advice ignores the series/parallel difference. Speakers connected in series sum the load of the individual speakers, so two 4 ohm speakers present a load of 8 ohms to the amp. In parallel, two 4 ohm speakers present a load of 2 ohms. Amplifiers do not like a load of less than the specified impedance. Wiring in series=positive terminal of amp to positive terminal of speaker A, neg terminal of A to positive of speaker B, neg of speaker B to neg of amp. Wiring in parallel=pos of amp to both speaker pos, neg of amp to both speaker negs. Edited July 29, 2013 by AussieBassman Quote Link to comment Share on other sites More sharing options...
TimR Posted July 29, 2013 Share Posted July 29, 2013 (edited) [quote name='AussieBassman' timestamp='1375138919' post='2157294'] This advice ignores the series/parallel difference. [/quote] Indeed. The question is can he plug a 4ohm cab into each speaker output. He can't. Because they're parallel. You can muddy the water by talking about the merits of additional volume from two speakers in series vs more power output to a single speaker and sensitivity. However, we're possibly talking about 2 dissimilar cabs and running them in series is going to cause all sorts of issues. Edited July 29, 2013 by TimR Quote Link to comment Share on other sites More sharing options...
icastle Posted July 29, 2013 Share Posted July 29, 2013 Yes. For the sake of clarity, when we talk about adding standard, off the shelf, factory built speaker cabs we are generally assuming that they being seen as a parallel load by the amp, because they generally are. Exceptions to that assumption would be adding extra speakers to a cabinet, having special cables assembled or rewiring a cabinet to intentionally run cabinets in series. Quote Link to comment Share on other sites More sharing options...
xgsjx Posted July 30, 2013 Share Posted July 30, 2013 [quote name='Jack Cahalane' timestamp='1375135221' post='2157228'] Something like this should be stickied, I spent ages trying to figure out what I needed until someone on here explained it as simply as this. Really helpful if you haven't got a clue like me [/quote] Funny enough, in the "Amps & Cabs" section, we have this... http://basschat.co.uk/topic/135-impedance-etc/ HTH. Quote Link to comment Share on other sites More sharing options...
andydye Posted July 30, 2013 Share Posted July 30, 2013 [quote name='AussieBassman' timestamp='1375138919' post='2157294'] This advice ignores the series/parallel difference. Speakers connected in series sum the load of the individual speakers, so two 4 ohm speakers present a load of 8 ohms to the amp. In parallel, two 4 ohm speakers present a load of 2 ohms. Amplifiers do not like a load of less than the specified impedance. Wiring in series=positive terminal of amp to positive terminal of speaker A, neg terminal of A to positive of speaker B, neg of speaker B to neg of amp. Wiring in parallel=pos of amp to both speaker pos, neg of amp to both speaker negs. [/quote] Yep indeed matey, I was going to append that obbm should be able to make a cable that would allow the connection of the 2 cabs in serial but decided against it given the manner of asking [quote name='icastle' timestamp='1375139911' post='2157303'] Yes. For the sake of clarity, when we talk about adding standard, off the shelf, factory built speaker cabs we are generally assuming that they being seen as a parallel load by the amp, because they generally are. Exceptions to that assumption would be adding extra speakers to a cabinet, having special cables assembled or rewiring a cabinet to intentionally run cabinets in series. [/quote] Precisely this Quote Link to comment Share on other sites More sharing options...
Coilte Posted July 30, 2013 Share Posted July 30, 2013 [quote name='icastle' timestamp='1375135897' post='2157246'] This is a nice little tool to keep in your Favourites. [url="http://ampservice.de/impcalc.php?lang=e"]http://ampservice.de...calc.php?lang=e[/url] [/quote] Yes that's a very helpful link alright. Here is another, which people might find helpful also. [url="http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html"]http://www.tunemybass.com/bass_amps/how_to_hook_up_heads_and_cabinets.html[/url] Quote Link to comment Share on other sites More sharing options...
neepheid Posted July 30, 2013 Share Posted July 30, 2013 [url="http://en.wikipedia.org/wiki/Impedance_(electrical)#Combining_impedances"]http://en.wikipedia.org/wiki/Impedance_(electrical)#Combining_impedances[/url] Quote Link to comment Share on other sites More sharing options...
Judo Chop Posted July 30, 2013 Share Posted July 30, 2013 [quote name='xgsjx' timestamp='1375164322' post='2157351'] Funny enough, in the "Amps & Cabs" section, we have this... http://basschat.co.uk/topic/135-impedance-etc/ HTH. [/quote] That's not what I was thinking, sure it explains it to you, but not as simply as the post in this topic Quote Link to comment Share on other sites More sharing options...
Dave_the_bass Posted July 30, 2013 Share Posted July 30, 2013 [quote name='jonnpip' timestamp='1375134904' post='2157221'] so i should know this by now the years ive been on bass but,if my genz benz 9.2 amp is 4 ohms and my berg cab is 4 too, is it not safe to hook a 2x12 4 ohms cab to the other output on the amp ? or does this reduce this to 2 ohms...advice please ? [/quote] This would be the exact reason I got the 12.2. All my favourite cabs are 4ohm and you never know when you might want to double up the cabs. N.B. - I said want to double cab, not need. I think 2 berg HD212's on the 12.2 amp is the dictionary definition of a weapon of mass destruction! Quote Link to comment Share on other sites More sharing options...
xgsjx Posted July 30, 2013 Share Posted July 30, 2013 [quote name='Jack Cahalane' timestamp='1375181820' post='2157634'] That's not what I was thinking, sure it explains it to you, but not as simply as the post in this topic [/quote] Good point. Quote Link to comment Share on other sites More sharing options...
discreet Posted July 30, 2013 Share Posted July 30, 2013 [quote name='neepheid' timestamp='1375173252' post='2157443'] [url="http://en.wikipedia.org/wiki/Impedance_(electrical)#Combining_impedances"]http://en.wikipedia....ning_impedances[/url] [/quote] You had to go and complicate matters, didn't you? Quote Link to comment Share on other sites More sharing options...
neepheid Posted July 30, 2013 Share Posted July 30, 2013 [quote name='discreet' timestamp='1375215304' post='2158415'] You had to go and complicate matters, didn't you? [/quote] [i]Moi? [/i] Quote Link to comment Share on other sites More sharing options...
jonnpip Posted July 30, 2013 Author Share Posted July 30, 2013 [sup][size=5]Ha, didnt mean too neepheid... [/size][/sup] Quote Link to comment Share on other sites More sharing options...
jonnpip Posted August 1, 2013 Author Share Posted August 1, 2013 [sup]I[size=6]Weeks ago i mentioned to a guy who works in the peavey factory near me in corby,asking him which way i should go,wheather to get a different amp or different speakers but he did say to me, there is a box i can make up where you can use the 4 ohm amp with two 4ohm cabs, ...he said,..[/size][/sup] [sup][size=6] [/size][/sup] [sup][size=6]Hi Jon, at present yo can't use the 2 cabs together as that would overload your amp ( 2 ohms ). The box I would make up will combine both cabs ( 8 ohms). You amp will only deliver about 2/3rd's of the power, but will seem louder, as you will be moving more air with 6 x speakers in total, plus the 2x10 cab will be higher ( earer to your ears ).[/size][/sup] [sup][size=6]Hope this explains it a bit clearer. ....cheers tom,[/size][/sup] [sup][size=6] [/size][/sup] [sup][size=6]so there is another option then im thinking !![/size][/sup] Quote Link to comment Share on other sites More sharing options...
icastle Posted August 1, 2013 Share Posted August 1, 2013 Yeah, that'll just be a little box that runs the two cabs in series. Quote Link to comment Share on other sites More sharing options...
TimR Posted August 1, 2013 Share Posted August 1, 2013 Jon. That is not the question you asked. These threads can quickly descend into nonsense as everyone jumps in to explain what can and can't be done. You CAN power both cabs from that amp BUT not by plugging them into the two outputs on the amp. That would mean the amp seeing 2 ohms. If the cabs are identical then you can run them in series using a different cable or 'special box'. If the cabs are different you will have very upredictable and possinly undesired results. Quote Link to comment Share on other sites More sharing options...
AussieBassman Posted August 6, 2013 Share Posted August 6, 2013 Censoring is alive and well on this forum. Long live freedom of speech. Quote Link to comment Share on other sites More sharing options...
icastle Posted August 6, 2013 Share Posted August 6, 2013 [quote name='AussieBassman' timestamp='1375822098' post='2166246'] Censoring is alive and well on this forum. Long live freedom of speech. [/quote] Where has this thread been censored? Quote Link to comment Share on other sites More sharing options...
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