DreadAlert Posted June 27, 2010 Share Posted June 27, 2010 Hey guys. I've been wondering about cabs and heads and combos and stuff recently. How do you know what kind of cab you can connect to the combo or the amp? Cause apparantly you could attack a 4x10 cab to a 20w combo as long as it has speaker out and I'm just wondering is there any scenario in which you couldn't? Lets say, if I bought this combo [url="http://www.guitarampkeyboard.com/en/rb-2/69083"]http://www.guitarampkeyboard.com/en/rb-2/69083[/url] and I wanted to attach a cab to it, which would work and which wouldn't? And why? Thanks, sorry if I seem a bit of a newb. -Dread- Quote Link to comment Share on other sites More sharing options...
JTUK Posted June 27, 2010 Share Posted June 27, 2010 it the combo amp runs a lead from the amp to the cab and has a jack then you could swap that out and run a cab...or if the combo has another external jack out from the amp to speakers...not effects, then you could pair that up as well. If it hasn't got any of these ..then the wiring is done internally or hidden and you'll have to make that available to add a cab. Most Combos would run at 8 ohms, IMO...so providing the amp will go to 4...then you'll need to add a cab to get its power rating anyway.. The amp in your link says it will take another cab and has an external speaker out..but at 30 wats...volume is going to be hard to find any which way you do it. That combo is a bedroom prcatise amp, IMV.. If you want more than that, I'd spend £125 on here in the For Sale section to get more watts.. and probably a better combo as well. IMHO. Quote Link to comment Share on other sites More sharing options...
thinman Posted June 27, 2010 Share Posted June 27, 2010 It's fine as long as the impedance of the cab is within the range that the amp is happy with. Most amps will drive a cab rated at 8 or 4 ohms. If you connect two 8 ohm cabs together in parallel then that's 4 ohms. Some amps will drive down to 2 ohms (two 4 ohm cabs in parallel) but for many amps that's pushing it a bit. An amp will be rated at a power output when connected to a specific impedance. E.g. an Ashdown MAG 300 is supposedly 300w into a 4 ohm load. The 20w you quote may be based on an 8 or 4 ohm load - hopefully it's written down somewhere. It should be safe to connect it to any 8 ohm cab and may be OK with a 4 ohm load. How loud it will be with a 4 x 10" depends very much on the efficiency of the cab. It might be suprisingly loud! Quote Link to comment Share on other sites More sharing options...
DreadAlert Posted June 27, 2010 Author Share Posted June 27, 2010 For that amp, it says: External Speaker Skt Minimum 8 Ohms. So does that mean i could connect 2 of these in parallel? [url="http://www.dolphinmusic.co.uk/product/37145-ashdown-mag-115-deep-cabinet-evo-ii-.html"]http://www.dolphinmusic.co.uk/product/3714...et-evo-ii-.html[/url] Also, what do you mean by parallel? Quote Link to comment Share on other sites More sharing options...
Colledge Posted June 27, 2010 Share Posted June 27, 2010 no, on that combo the minimum impedance of the external cab is 8ohm, so you would only be able to attach one of those cabs. (the amplifier minimum impedance is 4 ohms, the internal speaker will be 8ohms and the external speaker is 8ohms making the whole impedance 4ohms) but i'd highly advise you to not go for a small 30w combo and a larger 250w extension cab because for that kind of money you can get a much better and more powerful setup on here. Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted June 27, 2010 Share Posted June 27, 2010 [quote name='DreadAlert' post='878881' date='Jun 27 2010, 03:17 PM']Also, what do you mean by parallel?[/quote] Have a trawl through this: [url="http://wiki.basschat.co.uk/info:amps:impedance_and_wattage"]http://wiki.basschat.co.uk/info:amps:impedance_and_wattage[/url] It'll either blind you with science or fill you in, but it's a really good idea to get your head around Impedance & can save you from expensive disaster Pete. Quote Link to comment Share on other sites More sharing options...
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