SaxyBassist Posted February 14, 2015 Share Posted February 14, 2015 I am a complete electronics numpty and just wondered if anyone could clarify something for me! I have a Promethean 3110 combo (300 watts 8ohms) and want to add a extension cab - a TC Electronics RS 210 (400 watts 8ohms)......... I've been told this will work, but if I ever wanted to add another RS210 I'd need a more powerful head. My question is how comes the 400 watt RS210 is not to powerful for the Promethean 300watt Combo? and also what amp head would I need for 2 RS210s ? thanks in advance (ps please imagine you are explaining to a small child ) Quote Link to comment Share on other sites More sharing options...
chris_b Posted February 14, 2015 Share Posted February 14, 2015 Forget the watts for the moment. Your combo is running 1 cab at 8 ohms. Add a second 8 ohm cab and it will be running at 4 ohms. That is the limit for most amps. So 2 8 ohm cabs = 4 ohms = good. Add a third 8 ohm cab and you will be trying to run the amp at 2.67 ohms which will generate more heat and usually causes the amp to at best shutdown or worst cause damage. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted February 14, 2015 Share Posted February 14, 2015 Just to massively confuse matters don't some TC heads run 3x8 ohm cabs as long as they are all TC cabs? Quote Link to comment Share on other sites More sharing options...
chris_b Posted February 14, 2015 Share Posted February 14, 2015 This is the problem with combo's. If you want to upgrade one part you have to replace both parts. How loud do you want to play? If you want to run 2 210 8 ohm cabs you'll need a separate amp. 2 210 cabs and a 500 watt amp will be a great rig and you can keep the combo for playing at home or low volume rehearsals. I'd also suggest a 212 to pair with your separate amp. Quote Link to comment Share on other sites More sharing options...
chris_b Posted February 14, 2015 Share Posted February 14, 2015 [quote name='stingrayPete1977' timestamp='1423925725' post='2690435'] Just to massively confuse matters don't some TC heads run 3x8 ohm cabs as long as they are all TC cabs? [/quote] The TC heads that are advertised to run 3 cabs can run any 8 ohm cabs. There is nothing special about the cabs, just those amps can run down to 2.67 ohms. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted February 14, 2015 Share Posted February 14, 2015 What I meant is they only advise it with their own cabs as they can't vouch for other brands being 8 ohms can they? I like combos that have a removeable head, 1x12 combo at the dog and partridge one night then running a pair of 4x10s at the megadome gig the next night Quote Link to comment Share on other sites More sharing options...
BassBunny Posted February 14, 2015 Share Posted February 14, 2015 I think if you check further you will find the 3110 is already running at 4 Ohms, and thus the maximum 300W. The internal speaker has two 8 ohm voice coils wired in parallel thus you have the full 300 watts with the internal speaker. When you plug in the external speaker one of the 8 ohm windings is disconnected. So although an additional speaker will move more air, you already have the full 300W as the combo stands. Here's the info from the user manual. [attachment=183888:Promethian.png] Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted February 14, 2015 Share Posted February 14, 2015 (edited) To (maybe) answer you original question, there is no reason at all not to attach a 2x10 cab to your combo providing a socket is provided for plugging one in. It shouldn't do any harm. The benefit in your case, and according to athe answer above, will be more speaker surface giving you higher headroom (goes louder without distorting) and a greater perceived volume (because of more speakers). The cons fo this are few - more cabs to carry and half your power going to the internal speaker & the other half going to the 2x10, therefore more stress on the internal speaker. Could you borrow a 2x10 & try it? G. Edited February 14, 2015 by geoffbyrne Quote Link to comment Share on other sites More sharing options...
Musky Posted February 14, 2015 Share Posted February 14, 2015 I just thought I'd address the OP's question re the TC cab. Although the RS is rated at 400w the doesn't mean that an amp will put out 400W into it. It just means that it can handle up to 400w for prolonged periods of time - above that things will start to melt in the cab. So the cab can't be too powerful for the amp as it only receives the power, it doesn't pull the power from the amp. Quote Link to comment Share on other sites More sharing options...
SaxyBassist Posted February 14, 2015 Author Share Posted February 14, 2015 [quote name='chris_b' timestamp='1423925525' post='2690433'] Forget the watts for the moment. Your combo is running 1 cab at 8 ohms. Add a second 8 ohm cab and it will be running at 4 ohms. That is the limit for most amps. So 2 8 ohm cabs = 4 ohms = good. Add a third 8 ohm cab and you will be trying to run the amp at 2.67 ohms which will generate more heat and usually causes the amp to at best shutdown or worst cause damage. [/quote] Thanks that sounds good [quote name='chris_b' timestamp='1423925937' post='2690438'] This is the problem with combo's. If you want to upgrade one part you have to replace both parts. How loud do you want to play? If you want to run 2 210 8 ohm cabs you'll need a separate amp. 2 210 cabs and a 500 watt amp will be a great rig and you can keep the combo for playing at home or low volume rehearsals. I'd also suggest a 212 to pair with your separate amp. [/quote] At the moment I use the promethean alone for rehearsal, but hopefully will eventually play pubs/pub size venues. If bigger venues come up (that would be nice!) then I'd add a head and another RS 210 [quote name='stingrayPete1977' timestamp='1423926691' post='2690450'] What I meant is they only advise it with their own cabs as they can't vouch for other brands being 8 ohms can they? I like combos that have a removeable head, 1x12 combo at the dog and partridge one night then running a pair of 4x10s at the megadome gig the next night [/quote] Mine doesn't have a removeable head - would be good if it did [quote name='BassBunny' timestamp='1423927652' post='2690463'] I think if you check further you will find the 3110 is already running at 4 Ohms, and thus the maximum 300W. The internal speaker has two 8 ohm voice coils wired in parallel thus you have the full 300 watts with the internal speaker. When you plug in the external speaker one of the 8 ohm windings is disconnected. So although an additional speaker will move more air, you already have the full 300W as the combo stands. Here's the info from the user manual. [attachment=183888:Promethian.png] [/quote] Is that good or bad? Quote Link to comment Share on other sites More sharing options...
SaxyBassist Posted February 14, 2015 Author Share Posted February 14, 2015 [quote name='geoffbyrne' timestamp='1423928326' post='2690470'] To (maybe) answer you original question, there is no reason at all not to attach a 2x10 cab to your combo providing a socket is provided for plugging one in. It shouldn't do any harm. The benefit in your case, and according to athe answer above, will be more speaker surface giving you higher headroom (goes louder without distorting) and a greater perceived volume (because of more speakers). The cons fo this are few - more cabs to carry and half your power going to the internal speaker & the other half going to the 2x10, therefore more stress on the internal speaker. Could you borrow a 2x10 & try it? G. [/quote] Yes I've tried it - it sounds great! hmmm bit worried about stress on the internal speaker what does that mean? [quote name='Musky' timestamp='1423928691' post='2690475'] I just thought I'd address the OP's question re the TC cab. Although the RS is rated at 400w the doesn't mean that an amp will put out 400W into it. It just means that it can handle up to 400w for prolonged periods of time - above that things will start to melt in the cab. So the cab can't be too powerful for the amp as it only receives the power, it doesn't pull the power from the amp. [/quote] Thanks that makes sense Quote Link to comment Share on other sites More sharing options...
BassBunny Posted February 14, 2015 Share Posted February 14, 2015 "Is that good or bad? " Well neither really. It is just the fact there was an assumption that adding an extra cab would give you some additional power, it won't. It will however give you a greater speaker area, move more air and sound louder than the combo on on it's own. The only issue I can see with adding a 2x10 is that the 150w going to the extension cabinet will be shared between the 2 speakers, (75w each), whereas the speaker in the combo will be getting the full 150w. The thing is, if you've tried it and like it, go for it. You are now getting into the realms of speaker efficiency and that is a whole new can of worms. Personally I would use the matching Ibanez 1x10 extension cab. I did an experiment with my Markbass CMD121P and added various different 8Ohm extension cabs, none sounded as good as the NY121, which is designed for the job. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted February 14, 2015 Share Posted February 14, 2015 I have confused you more thinking this was a TC product rather than Ibanez! ignor everything I said, Lol. Quote Link to comment Share on other sites More sharing options...
chris_b Posted February 14, 2015 Share Posted February 14, 2015 [quote name='stingrayPete1977' timestamp='1423926691' post='2690450'] What I meant is they only advise it with their own cabs as they can't vouch for other brands being 8 ohms can they? [/quote] That is only a marketing ploy. Any 3 8 ohm cabs will work with the TC heads because these heads go to 2.67 ohms. I used to use 3 Bergantino cabs. Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted February 14, 2015 Share Posted February 14, 2015 Well there is only one thing better than a Bergatino cab....more Bergatino cabs! Quote Link to comment Share on other sites More sharing options...
taunton-hobbit Posted February 14, 2015 Share Posted February 14, 2015 I hate to be obvious, but if I want more volume/power, I add another amplifier (and speaker/s if not a combo) - dilemma sorted........... Quote Link to comment Share on other sites More sharing options...
Musky Posted February 14, 2015 Share Posted February 14, 2015 [quote name='chris_b' timestamp='1423934973' post='2690580'] That is only a marketing ploy. Any 3 8 ohm cabs will work with the TC heads because these heads go to 2.67 ohms. I used to use 3 Bergantino cabs. [/quote] Probably. The thing is speakers are rated at the lowest point in their impedance curve and then rounded off to the nearest standard point, which with bass cabs is usually 2, 4 or 8 ohms. So if the TC amp can only be truly used safely down to 2.67 ohms and the 3 8 ohm cabs you choose to pair it with happen to actually dip below 8 ohms you might find yourself in trouble. So TC are just covering themselves really. And trying to sell more of their products. Quote Link to comment Share on other sites More sharing options...
SaxyBassist Posted February 14, 2015 Author Share Posted February 14, 2015 [quote name='taunton-hobbit' timestamp='1423936144' post='2690597'] I hate to be obvious, but if I want more volume/power, I add another amplifier (and speaker/s if not a combo) - dilemma sorted........... [/quote] As I said I am a complete techno numpty and can't even change a light bulb - ergo it is not obvious to me at all I have the Promethean and just want to add something safely on to it so I have a beefier sound Quote Link to comment Share on other sites More sharing options...
Musky Posted February 14, 2015 Share Posted February 14, 2015 (edited) [quote name='taunton-hobbit' timestamp='1423936144' post='2690597'] I hate to be obvious, but if I want more volume/power, I add another amplifier (and speaker/s if not a combo) - dilemma sorted........... [/quote] I think it depends on where you're starting from really. Doubling the number of speakers and halving the impedance can give up to a 6dB increase in volume, equivalent to four times the power. So if someone's using a 500W amp they'll be looking for a 2000W amp (and most likely the speakers to handle it). It just ends up being a different kind of dilemma. Edit: I just realised you said [i]another[/i] amplifier and speakers. As you were... Edited February 14, 2015 by Musky Quote Link to comment Share on other sites More sharing options...
taunton-hobbit Posted February 14, 2015 Share Posted February 14, 2015 (edited) Can I offer a real-life example? Back in the Stone Age I did a short residency at the Marquee with David Bowie - he used, as I recall, a 50watt WEM amp and a set (pair) of column speakers - after the first gig, he came back with a duplicate set of kit and two mics, taped together, so he had a 100watt pa, using two amps, four speakers and two mics - it's easier these days........... .....................I realise that op was posting about bass, but the same principle applies............ Edited February 14, 2015 by taunton-hobbit Quote Link to comment Share on other sites More sharing options...
RickyV Posted February 14, 2015 Share Posted February 14, 2015 Hi, as an equal electronics numpty, new to the wonders of bass amps can I jump into this thread and ask a similar question as I am still confused with my own personal situation. I have an Ashdown Combo, an EB Evo ii 180. This states on the back of the unit 180 Watts RMS and 300 watts peak. Speaker output is stated as 4 ohms load. The spec in the booklet says [b]minimum [/b]impedanceof 4 ohms if that makes any difference. My main question being what are my options/limitations for adding an extension cab in terms of watts and ohms? Any specific Ashdown recommendations also welcomed. Cheers Quote Link to comment Share on other sites More sharing options...
taunton-hobbit Posted February 14, 2015 Share Posted February 14, 2015 If it says minimum, it means it won't like 2 ohms a lot (burning smell) - I'd talk to Ashdown, but I think, like many, you are trying to get out of a situation at the minimum cost - nothing wrong with that, but 'yer gets wot yer pays for' at the end of the day............... Quote Link to comment Share on other sites More sharing options...
stingrayPete1977 Posted February 14, 2015 Share Posted February 14, 2015 Most combos run 4 ohms min load and an 8 ohm built in speaker (unlike the unusual one the OP has), so you can add another 8 ohm cab underneath to get a 4 ohm load (2 8s divided by 2 cabs equals 4) that will give you the full 180 watts the amp can produce hence you get more power and more driver area, double whammy upgrade! If the head can be unplugged from the combo cab you could run any combination of cabs as long as they combine to a total of at least 4 ohms (4 x 16 ohm 2x10 cabs all wired in parallel, 2 x 8 ohm 4x10 cabs, a single high quality 4 ohm 2x12, etc etc Quote Link to comment Share on other sites More sharing options...
SaxyBassist Posted February 14, 2015 Author Share Posted February 14, 2015 What part of "please imagine you are explaining to a small child" do you guys not understand? Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted February 14, 2015 Share Posted February 14, 2015 [quote name='SaxyBassist' timestamp='1423944180' post='2690769'] What part of "please imagine you are explaining to a small child" do you guys not understand? [/quote] Try this first; come back here if questions subsist... [url="http://www.studybass.com/gear/bass-amps/"]Bass amps and cabs, beginner's guide...[/url] There's no problem with asking questions. Sooner or later it will 'click'. It's not rocket surgery. Quote Link to comment Share on other sites More sharing options...
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