Meegs Posted July 13, 2006 Report Share Posted July 13, 2006 So i have 2 Sound Stream Picasso 1400.1D mono block amps rated at 12V. They are rated at 1400w RMS. They cost some heavy coin, and have a good name in the stereo market. Are they the best there is NO, so please don't tell me that there are other manufactures that are better. BUT, none-the-less they are at the minimum somewhat legit... I have 1-60A circuit breaker 10" off my stock battery that is charged by my stock alternator. the amps are supplied by 2ga fine multi strand welders wire. at the most I assume i have 60A with 12V. so the highest wattage i should see is 60*12=720 and that is 25% of advertised manufacture power rating. screw 14.4 it will still take a lightning strike to get it any where close to Manf advertised ratings. 60*V=2800 V=46.667 my honest question here is what is going on here? yes i know about the 3db rule and double power. but if i were to go out and get MORE amps or bigger amps it would get louder. step-up transformer is not the correct answer. ~Meegs Quote Link to comment Share on other sites More sharing options...
misterp Posted July 13, 2006 Report Share Posted July 13, 2006 (edited) Short answer - the label on the amp jives with the 60A power lead fusing (that's a single 60A fuse per 1400.1D amplifier, or two 60A fuses). I pretty-much ignore all labeling on car audio, as this equipment is not federally regulated like home audio components are - the only thing that you can usually count on is (1) the size of the master power and ground leads, and (2) the size of the fuse(s); those two things will dictate total input to the secondary side of the amp. SO - assuming: 14.4v alternator voltage * 60 A = 864-watts DC, and also assuming that your Class-D amp is 85% efficient (85% goes to the speakers, 15% goes up in heat) that means 735-watts output into 1-ohm (again, per amplifier). Since we do not listen to signals with constant voltage (DC) but rather sine waves (varying AC voltage) that means each amplifier will support 735-watts "average" (or RMS) watts, so the voltage rails are probably powerful enough to deliver a 1400-watt 'burp' if driven 100%, but only for a short instant; if you are using slow-blow fuses/breakers then this is probably real-world achievable, ASSUMING that your alternator is capable of maintaining 14.4v output while under a 120A load (not many can do this, certainly not the factory Delco one). You used a figure of 12.0-volts in your calculations, actually resting battery voltage is 12.6-volts and as the alternator output sags under demand real measured line voltage will probably be anywhere from 12.6 to 14.4. One can also get custom aftermarket alternators and battery systems running 16.0 volts... Mr. P. edit - I did some quick reverse-math, to deliver an honest 1400-watts to the driver the secondary side of an amp must have 51-volt power rails I wonder what the actual design spec on this amp is... The 2-ga wire is correct for your application btw Q: did you upgrade your cab-to-frame/engine ground to 2-ga as well? Another thought - to double the amount of sound (+3-db) with the same effective cone area in the same existing enclosure, you need an entire order of magnitude more power as this performance follows a logarithmic curve, i.e. you need to go from 1400-watts RMS to 14000-watts RMS . It will be far easier and less costly to double the effective cone area (go from 10's to 12's, or 12's to 15's, or round to square, double the number of drivers, etc) or use a more efficient box design. Edited July 13, 2006 by misterp (see edit history) Quote Link to comment Share on other sites More sharing options...
Krambo Posted July 13, 2006 Report Share Posted July 13, 2006 Meegs, Confusing stuff huh? I have been in competition car audio for many years (dB Drag) and have met many engineers from large companies. Here is my opinion, take it for whatever it is worth: I have only found 2 manufacturers (in 2001) that have amps that produce their advertised specs (MMATS and USAmps). Zapco and Orion's HCCA line was close. I could care less what the specs say, do a physical test and go from there. Its kind of like talking about how much power your motor has where whereas the power to the wheels is what is important right? Get a CD that has a 60Hz tone on it and play it at the power level before your subs distort or the amp goes into clipped signal (remember we are playing a SINGLE tone here). Be sure that your low pass X-over is set ABOVE 60 Hz. Shut down the system and let it cool for a while. Take a high quality volt meter and measure the output on the SPEAKER leads during a 3 second burp. Take that number and divide it by the actual Impedance of the subs or what the amp "sees". (Since you have the volt meter handy, measure the resistance,...it isn't always what it seems or advertised for subs.) Do this with the amp off. This calculation you did is what the amp draws from your system (current). You can take that number and multiply it by the measured number from before (Volts) and get your root mean square value (RMS) in Watts. These real world numbers take the guess work out of your amps advertised specs. This eliminates the slew rate, effeciency, THD and Damping factor. Quote Link to comment Share on other sites More sharing options...
misterp Posted July 13, 2006 Report Share Posted July 13, 2006 ...I have only found 2 manufacturers (in 2001) that have amps that produce their advertised specs (MMATS and USAmps). ... Does US Amps no longer make Soundstream reference amps Mr. P. Quote Link to comment Share on other sites More sharing options...
Krambo Posted July 14, 2006 Report Share Posted July 14, 2006 ...I have only found 2 manufacturers (in 2001) that have amps that produce their advertised specs (MMATS and USAmps). ... Does US Amps no longer make Soundstream reference amps Mr. P. My two teammates went to us amps factory one time. They were closing up shop when they were there. Mostly everthing is going over seas to be built for cost reasons. US amps only bulit their line and were starting to expand in lower lines at that time. Not sure if Soundstream was one of them. Jack sold the company. It will be based (corporate) out of Cali. with some shipping in Fl that last I heard. Most companies have a few "Namebrand" lines that they manufacture side by side. One happens to be Digital Designs who makes their own line of subwoofers and also makes the Juggernaut for MMats. They have slightly different specs and some royalties are paid by MMats. They make the highest quality drivers IMO and they are all hand built in the USA FYI, We tested the MMats class D's pulling over 240 amps at 15 volts and a 1.3 OHM load. Quote Link to comment Share on other sites More sharing options...
fox_forma Posted July 14, 2006 Report Share Posted July 14, 2006 this stuff is all gibberish to me, what exactly are you guys saying? I was just thinking about what size inline fuse I need to run for my amp and this kinda seems like what you guys are talking about but its all mumble jumble to me trying to read it. If it is what i'm thinking about I have a 60A inline fuse now and i'm about to run around 800wrms Is that ok? Quote Link to comment Share on other sites More sharing options...
misterp Posted July 14, 2006 Report Share Posted July 14, 2006 ...FYI, We tested the MMats class D's pulling over 240 amps at 15 volts and a 1.3 OHM load. OH.. MY.. GAWD.. Quote Link to comment Share on other sites More sharing options...
misterp Posted July 14, 2006 Report Share Posted July 14, 2006 this stuff is all gibberish to me, what exactly are you guys saying? I was just thinking about what size inline fuse I need to run for my amp and this kinda seems like what you guys are talking about but its all mumble jumble to me trying to read it. If it is what i'm thinking about I have a 60A inline fuse now and i'm about to run around 800wrms Is that ok? Yes that is kinda what we are discussing. In simple terms - 1) ALWAYS use the size and type of fuse the manufacturer specifies, do not deviate! 2) make sure that you have the correct size wiring from the charging system to the amp(s), and again from the ground back to the engine/frame - if it is too small you risk burning something up and too large costs more $$$ (there are charts on the internet with this information); 3) verify that the charging system does not fall below 14.4V at full volume, if so you need to fortify with stiffening caps and/or better alternator. Mr. P. Quote Link to comment Share on other sites More sharing options...
04CHASE Posted July 14, 2006 Report Share Posted July 14, 2006 i can vouch for mmats also , i had a 2400 x 0.5 ohm amp ran by 2 optima yellow tops and a 300 amp alt. 0 gauge wire all the way around 250 breakers and pushing 3 12 w7 woofers to i think it was 32hz. i miss the system alot i wish i had it still. id guess it hit around 150 db. was a cool set up Quote Link to comment Share on other sites More sharing options...
Meegs Posted July 15, 2006 Author Report Share Posted July 15, 2006 (edited) Humm... all interisting points! I'm not complaining about my stereo; rather it is everything i ever wanted. I was just wondering how Soundstream gets off saying the amps have a manufacturers advertised rating of 1,400W each. I call B.S. but who am i and what can i do. I did upgrade the gound wire. i also added a bunch more ground wires! I have owned about a dozen or more 4.3L S-10's and i was always having small problems that i beat my head against, usually most would be due to a simple ground. some aspect of GM, that i never understood. 2-soundstream amps 2 Kicker solos s12L7's factory bose after that! I love the setup, i just have no concrete proof of how much watts i am pushing. but i can only tell you...I know it's more than enough! ^ for a daily driver i am sure it is not @ 150db. but i was not going for that goal either! Edited July 15, 2006 by Meegs (see edit history) Quote Link to comment Share on other sites More sharing options...
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