waynepunkdude Posted March 27, 2009 Share Posted March 27, 2009 The other night I borrowed a cab from another band, the guy had a 2 X 10 and a 1 X 15 both 4ohms so with my 4ohm head I only used 1 well that's what I thought until after we had played when the soundman said "I plugged the other one in for you, you can use both you know?" I almost hit him, anyway it all sounded fine but would the knob have caused any lasting damage? Quote Link to comment Share on other sites More sharing options...
josh3184 Posted March 27, 2009 Share Posted March 27, 2009 (edited) only if you turned it up a ton (i think) but that soundguy is retarded Edited March 27, 2009 by josh3184 Quote Link to comment Share on other sites More sharing options...
EBS_freak Posted March 27, 2009 Share Posted March 27, 2009 [quote name='josh3184' post='447440' date='Mar 27 2009, 04:03 PM']only if you turned it up a ton (i think) but that soundguy is retarded[/quote] Too late to worry about it now. If your amp is still working... count yourself lucky. Soundguy needs shooting. Quote Link to comment Share on other sites More sharing options...
The Funk Posted March 27, 2009 Share Posted March 27, 2009 What an absolute arse! If your amp is still working, it's still working. I've made that mistake before once - but with my own equipment, not someone else's! Quote Link to comment Share on other sites More sharing options...
joegarcia Posted March 27, 2009 Share Posted March 27, 2009 What a twonk. Don't think it could cause any problems that aren't obvious that might creep up later. So yea, if it's still going then you're fine. Quote Link to comment Share on other sites More sharing options...
cLepto-bass Posted March 27, 2009 Share Posted March 27, 2009 Does anyone know what problems would be likely to arrise. I'm not all that clued up on this Ohm stuff. Quote Link to comment Share on other sites More sharing options...
Hamster Posted March 27, 2009 Share Posted March 27, 2009 If it was going to pop, it would of done so on the night Quote Link to comment Share on other sites More sharing options...
cheddatom Posted March 27, 2009 Share Posted March 27, 2009 The amp would only see 2ohms and so over-heat and explode? Quote Link to comment Share on other sites More sharing options...
escholl Posted March 27, 2009 Share Posted March 27, 2009 "explode" might be a bit dramatic. But no, your amp should be fine. Most well built amps are much tougher to kill than people give them credit for...current limiting, output protection...it's all there for a reason! Plus even if the amp says 4 ohm minimum, many can handle a 2 ohm load anyways -- not recommended, of course. Your amp will be fine. Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted March 27, 2009 Share Posted March 27, 2009 I was thinking about the 2 ohm amps I had seen, and the common factor is huge heatsinks, is being capable of 2 ohm mostly a case of being able to control some fairly serious heat? Quote Link to comment Share on other sites More sharing options...
waynepunkdude Posted March 27, 2009 Author Share Posted March 27, 2009 Cheer for the answers guys, I'm happier now. That soundguy was such a cockhead. Quote Link to comment Share on other sites More sharing options...
alexclaber Posted March 27, 2009 Share Posted March 27, 2009 [quote name='Mr. Foxen' post='447770' date='Mar 27 2009, 11:00 PM']I was thinking about the 2 ohm amps I had seen, and the common factor is huge heatsinks, is being capable of 2 ohm mostly a case of being able to control some fairly serious heat?[/quote] I think that's the main factor. There's also the issue of not being able to deliver enough current but I don't know whether that's likely to cause damage anywhere within the amp. But it's the increased current flow and the reduced amp efficiency that causes more heat output from the power transistors and thus overheating issues. This is why the AccuSwitch survived so long - if you're using a pair of dual woofer (i.e. big!) AccuGroove cabs you're unlikely to be pushing an amp hard enough to get failure due to excessively low impedance. I know one bassist whose amp died on a outdoor gig though. It's soundmen like that that taint the good ones' names! Honestly... Alex Quote Link to comment Share on other sites More sharing options...
escholl Posted March 28, 2009 Share Posted March 28, 2009 [quote name='Mr. Foxen' post='447770' date='Mar 27 2009, 11:00 PM']I was thinking about the 2 ohm amps I had seen, and the common factor is huge heatsinks, is being capable of 2 ohm mostly a case of being able to control some fairly serious heat?[/quote] As Alex mentioned, there are some serious demands on the power supply as well, if the power supply is operated at or beyond its intended limit (ie if it needs to provide more current than it is capable of) then it is likely that either the power supply will fail due to thermal stress or the transformer itself will fail, again from too high of a current draw likely causing overheating and triggering the internal thermal fuse. Large current draws cause power supply rail sag as well -- this is sometimes exploited in tube amplifiers, but is really only detrimental in SS ones. The huge heatsinks are because every time the current through the output stage is doubled, the power dissipated by the output transistors is multiplied by four. Which causes them to heat up, which causes their internal resistance to lower, which causes more current flow, which causes them to heat up more -- and so on, in a condition known as thermal runaway. Silicon transistors can run comfortably and sometimes even best at around 60 to 90 degrees C, but once this gets up to the critical temperature of around 150 C then that's the end of it. Quote Link to comment Share on other sites More sharing options...
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