bucko Posted January 19, 2011 Share Posted January 19, 2011 To add say a 4 ohm ext cab to my Nemesis nc 250 combo,does ext cab have to be wired in series as the speaker ext output is wired in series,or can I use a parrallel wired cab?.Also would it be safe to use a 2 ohm cab to get close to using full wattage from the combo. Many thanks,if anyone can give me advice on this. Quote Link to comment Share on other sites More sharing options...
ShergoldSnickers Posted January 19, 2011 Share Posted January 19, 2011 [quote name='bucko' post='1095140' date='Jan 19 2011, 01:48 PM']To add say a 4 ohm ext cab to my Nemesis nc 250 combo,does ext cab have to be wired in series as the speaker ext output is wired in series, or can I use a parrallel wired cab?.Also would it be safe to use a 2 ohm cab to get close to using full wattage from the combo. Many thanks,if anyone can give me advice on this.[/quote] I assume you have the single 15" speaker version of the combo? Adding a 4 ohm cab will give you a total of 12 ohms load, and a 2 ohm cab a total of 10. It's the combo that controls the wiring to the extension cab. It adds in series whatever is the nominal value for the particular extension cab being added. To get a 4 ohm load - the amp section is capable of delivering into a 4 ohm load, the extension jack on the combo would have to be rewired. This is not as straightforward as it may seem, as the jack has additional components - or so I'm led to believe. Any decent techie should be able to work out what is going on and rewire to parallel. Adding an 8 ohm cab would then get you the 4 ohms. Hope this helps. Quote Link to comment Share on other sites More sharing options...
bucko Posted January 19, 2011 Author Share Posted January 19, 2011 [quote name='ShergoldSnickers' post='1095543' date='Jan 19 2011, 07:41 PM']I assume you have the single 15" speaker version of the combo? Adding a 4 ohm cab will give you a total of 12 ohms load, and a 2 ohm cab a total of 10. It's the combo that controls the wiring to the extension cab. It adds in series whatever is the nominal value for the particular extension cab being added. To get a 4 ohm load - the amp section is capable of delivering into a 4 ohm load, the extension jack on the combo would have to be rewired. This is not as straightforward as it may seem, as the jack has additional components - or so I'm led to believe. Any decent techie should be able to work out what is going on and rewire to parallel. Adding an 8 ohm cab would then get you the 4 ohms. Hope this helps. [/quote] Thanks for that bit of info Shergold,as Idont know much regarding ohms etc. Sorry Ishould have said its the 2x10 version I have. Cheers. Quote Link to comment Share on other sites More sharing options...
ShergoldSnickers Posted January 20, 2011 Share Posted January 20, 2011 [quote name='bucko' post='1095631' date='Jan 19 2011, 08:35 PM']Thanks for that bit of info Shergold,as Idont know much regarding ohms etc. Sorry Ishould have said its the 2x10 version I have. Cheers.[/quote] Aaaahhhhhhh - the 2 by 10 combo is already set to have the speakers give a 4ohm load. I'd leave it as it is, and find a 4 ohm cab to go with it. Whilst the wattage available from the amp will drop, this should be more than offset by the increased number of speakers radiating sound. Doubling the impedance from 4 to 8 ohms by adding another 4 ohm cab will give the amp an easier time and would not affect the perceived volume too much if this were the only consideration. However, dropping the volume is the opposite of what is needed, even if only slightly. However, by adding more speakers, we are adding more radiating area. Put a ruler in a vice and twang it - not very loud. Now clamp the ruler to a table and twang it. Much louder, as the table has increased the area radiating the sound. It's the same with adding speakers. So, you'll lose some volume due to the impedance rise, but gain more than you lose by increasing the number of speakers. The question is... is the gain enough? Not sure if I'm totally honest as I've never tried this! Another way round this is to pick up another Nemesis combo, and slave it to the one you already have. Much louder now. As it happens, (warning: shameless plug) I just happen to have a 1 x 15 version available, once the transformer has been looked at (it hums too much and needs sorting). Quote Link to comment Share on other sites More sharing options...
bucko Posted January 21, 2011 Author Share Posted January 21, 2011 Shergold, thanks again for your advice on this. Adding another combo seems the best move,although old story money is tight and Im trying to sell a Markbass 115 standard hr 400 watt 8 ohm cab ,not getting used.Gigs have started to get less and less at the minute.But keep me posted if you decide to sell your 115 combo. once again thank you for taking time and your info. Cheers bigtime. Quote Link to comment Share on other sites More sharing options...
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