Members RoboPimp Posted August 27, 2005 Members Share Posted August 27, 2005 I have two yamaha P7000S amps and they say they can run 2 ohm stereo. In fact I've done it on one occasion and it worked fine. Is that an idication that I should be OK to do this full time? Or can this cause "gradual" excessive wear and tear? I already use three 8 ohm speakers on one half of the amp for a 2.66 load or whatever it is and it works great, no excessive clipping and never even seems to get warm. Just wondering if that one additional speaker would cause the untimely destruction of my amp. This would be for monitors, I would have 4 across the front all on the same mix. sorry if this is another stupid Q Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 27, 2005 Members Share Posted August 27, 2005 Shouldn't be a problem, especially for monitors. The EEE circuit really reduces the thermal load on the output stage. Link to comment Share on other sites More sharing options...
Members dboomer Posted August 27, 2005 Members Share Posted August 27, 2005 Originally posted by RoboPimp they say they can run 2 ohm stereo. In fact I've done it on one occasion and it worked fine. Is that an idication that I should be OK to do this full time I wouldn't do it as standard operating proceedure ... even if the amps are rated for two ohms ... even ours Rated means they won't blowup ... right away, but it doesn't mean it's the best way to do it either. I wouldn't plan to run normal amps into a 2 ohm load except for emergencies (no matter what Andy thinks:D ) Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 28, 2005 Members Share Posted August 28, 2005 Is that a "2 ohm challange" Don? I accidently left our 1200 watt module running at 2 ohms over the weekend and when I came back Monday morning everything was warm, ESPECIALLY my fan cooled load bank, but nothing had exceeded thermal limits. It really depends on the details, and you really have no control over these details. There are many amps rated at 2 ohms that do not fare nearly as well IME. That's one thing that seperates the men from the boys. Many of Don's pro amps actually do just fine at 2 ohms as well as much of the pro Crest product line. Of course there are models (of all Brands and products) at lower price points that do not have as much thermal headroom as a result of cost and weight cutting. Link to comment Share on other sites More sharing options...
Members Unalaska Posted August 28, 2005 Members Share Posted August 28, 2005 +1 on DBoomer's comment. I use P7000's and P5000's and have had no issues with 2ohm load (I did blow one up due to a short circut, it didn't like it much). The yamaha's run cool no matter what load is present. I ran 4 double 18's off a P7000 (no choice, I blew the other one up!) and it filled a ballroom of 400 people just fine. In a pinch it'll do but I wouldn't recommend it as everyday practice. Besides, they are relatively cheap and lightweight, buy another... p Link to comment Share on other sites More sharing options...
Members jverbarg Posted August 28, 2005 Members Share Posted August 28, 2005 +2 for dboomer... If you look at the specs on most amps, the rated Total Harmonic Distortion is many times higher going from 4ohms to 2ohms! Will it damage it? Not if it's rated for it. Will it sound worse than running at 4ohms? Most likely will. Even the general audience noticed the improvement in clarity of sound when I simply went to fewer speakers to run at 4ohm loads. Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 28, 2005 Share Posted August 28, 2005 Personally, I hate being backed into a corner... even if it's cheap and convenient. Putting all your eggs in one basket works fine if the basket doesn't fail, but Mr. Murphy is a heartless bastard. I've had my dealings with Mr. Murphy in the past and I've decided I like having options (and Mr. Murphy can go to hell). Designing your rig to operate at 2 ohms paints yourself into a corner. My FOH rig consists of 6 amps all running 4 ohms stereo. I have an amp rack sitting behind each stack. I pack a few extra long speaker and patch cables to every show. Any amp, any crossover, any anything can fail miserably and in a New York minute, I can patch around the problem and carry on like nothing is wrong. Yea... I could get away with running 1/2 the amps I run in my FOH rig (and my monitor rig for that matter), but I get a great deal of comfort knowing my back isn't against the wall, and Mr. Murphy can try me, but he's not going to steal the show. Link to comment Share on other sites More sharing options...
Members dboomer Posted August 28, 2005 Members Share Posted August 28, 2005 Back to the original question ... I guess it breaks down to "should I" or "can I". How comfortable are you living how close to the edge? For me, I would never start out with a system designed to be run at 2 ohms. As I said before ... I'd leave it as my emergency backup plan. It seems like so many threads on this board are asking "how loud can I get it" not "how good can I get it loudly" You "can" but I "wouldn't" ... YMMV Link to comment Share on other sites More sharing options...
Members agedhorse Posted August 28, 2005 Members Share Posted August 28, 2005 Originally posted by jverbarg +2 for dboomer... If you look at the specs on most amps, the rated Total Harmonic Distortion is many times higher going from 4ohms to 2ohms! Will it damage it? Not if it's rated for it. Will it sound worse than running at 4ohms? Most likely will. Even the general audience noticed the improvement in clarity of sound when I simply went to fewer speakers to run at 4ohm loads. If you look at the THD vs output power curve for any modern high feedback amplifier, the THD curve is very flat and low until you approach the clipping point where it rises very steeply. If you take the "standardized" 1% point at 2 ohms (essentially the clip point) and back it down 50 watts, you will find little difference between the 2 ohm and 4 ohm measurement. If you found it sounded better with fewer cabinets (no surprise here), it is more likely that the improvement was due to a reduction in comb filtering effect or other anomoly from constructive and destructive interference... or you have amplifiers that are not truely designed for 2 ohm operation. There are marketing guys out there that will "improve" an amp's marketability by adding a 2 ohm spec even though the amp is well into VI protection by that time. Think DJ and low end Asian MI products. Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 28, 2005 Share Posted August 28, 2005 Originally posted by agedhorse If you found it sounded better with fewer cabinets (no surprise here), it is more likely that the improvement was due to a reduction in comb filtering effect or other anomoly from constructive and destructive interference... or you have amplifiers that are not truely designed for 2 ohm operation. I believe a possible contributing factor might be that some amps can be driven to clip very easily operating at 2 ohms stereo. It happens so fast, and even though the clip lights might not be illuminating, I suspect the amp might be running well into clip anyway. Originally posted by agedhorse There are marketing guys out there that will "improve" an amp's marketability by adding a 2 ohm spec even though the amp is well into VI protection by that time. Think DJ and low end Asian MI products. In the late 1940's the land speed record for a stock factory bike was set at 150.313 mph on a Vincent Black Shadow. There-after Vincent Black Shadow motorcycles sported a 150mph speedometer (since it was proven that the stock Vincent Black Shadow was capable of that performance). For about 20 years, the Vincent land speed record was unbroken at 150.313 mph. I seem to remember seeing quite a few other bikes from the 60's sporting 150mph speedometers built when the Vincent was the only stock factory bike that was proven to be worthy of a 150mph speedometer. Yea... uh-huh. 150mph. Possibly in free-fall. Well anyway... it's just a short story illustrating marketing schemes. Link to comment Share on other sites More sharing options...
Members kayak Posted August 28, 2005 Members Share Posted August 28, 2005 P7000S owner's manual I may have just missed it, I skimmed over it VERY quickly, but I did not see anywhere in the manual where it said it was designed for a 2 ohm load. On page 9 it says that the minimum speaker impedance for stereo mode is 4 ohm, and for bridged mode, 8 ohm. Link to comment Share on other sites More sharing options...
Members Unalaska Posted August 28, 2005 Members Share Posted August 28, 2005 Originally posted by kayak P7000S owner's manual I may have just missed it, I skimmed over it VERY quickly, but I did not see anywhere in the manual where it said it was designed for a 2 ohm load. On page 9 it says that the minimum speaker impedance for stereo mode is 4 ohm, and for bridged mode, 8 ohm. Last page of the manual with all the specs: It rated the P7000 for 1kHz, 20 ms non-clip at 1600w X 2 stereo 2 ohm and 3200w X 1 bridged at 4 ohms. It's not a new thing that yamaha does this. I had a pair of XS350 amps that had a 2 ohm rating the same way. Basically Yamaha is saying 2 ohms is ok sparingly. I wouldn't design a system around it, but there are very few amps that it would be ok for. Even on page 9 of the manual it shows hookup diagrams and lo and behold: 4 ohm minimum impeadance in stereo and 8 ohm in mono. Given the fact a lot of people are going to use this amp who may not have a clue how these work I think they are just trying to cover thier ass. p Link to comment Share on other sites More sharing options...
Members jverbarg Posted August 28, 2005 Members Share Posted August 28, 2005 Originally posted by agedhorse If you found it sounded better with fewer cabinets (no surprise here), it is more likely that the improvement was due to a reduction in comb filtering effect or other anomoly from constructive and destructive interference... or you have amplifiers that are not truely designed for 2 ohm operation. The amp was a powered crate mixer, forget what model, but I think it was rated for it. The speakers were some 20-30 year old laminated boxes that where hung in a center cluster config that weren't even designed for flying. Wouldn't be surprised if both your statements are actually true. Fortunately I don't have to deal with that system anymore. Link to comment Share on other sites More sharing options...
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