Stetsom 7kd 16v, 7kd 12v, New 7k2d moddified 12v compared.
 

I'll make this clear now since most people won't read to far into post and only look at numbers. This is only a spl and power comparison test. The NSB90 battery used in test is a 4 year old NSB90 that is about .5db down from newer NSB90. The battery is good for burps but doesn't have the the amps it used to. CS9000 is almost new.

This test is to compare 7KD 16v, 7KD 12v and new 7K2D modified 12v version.
NOTE: Seven 2200mf capacitors added to 7K2D to make it a 12v version. Standard 7K2D is as strong as the older 7KD 12v and more efficient.

7KD 16V @.5ohms Only mod is copper bars instead of fuses.

NSB90: 3200-3300w, voltage drop 10.7v, 153.0db

CS9000: 4200-4300w, voltage drop 11.3v, 153.8db
Video
http://s171.photobucket.com/albums/u307/dtbrown1978/?action=view&current=SANY0399.flv

7KD 12V @ .5ohms

NSB90: 4000-4100W, voltage drop 10.4v, 153.5db
Video
http://s171.photobucket.com/albums/u307/dtbrown1978/?action=view&current=SANY0400.flv
CS9000: 5000-5200W, voltage drop 10.7v, 154.3db
Video
http://s171.photobucket.com/albums/u307/dtbrown1978/?action=view&current=SANY0404.flv

7K2D Modified 12V @.5ohms (Seven 2200mf capacitors added. Standard 7K2D is as strong as the older 7KD 12v and more efficient)

NSB90: 4200-4300w, voltage drop 10.3v, 154.0db
Video
http://s171.photobucket.com/albums/u307/dtbrown1978/?action=view&current=SANY0410.flv
CS9000: 5500-5600w, voltage drop 10.7v, 154.7-154.8db
Video


Conclusion is that the new 7K2D 12v is more efficient than the older 7KD by a lot. The 7K2D has same voltage drop as older 7KD 12v and is .5db louder shows it's efficiency. This amp wants to produce even more power and I can see this amp easily producing it's rated power at 12.6v. Fantastic job Stetsom. You really needed a more efficient amp and you went above and beyond that. Can't wait to test it at 1ohms for music on two CS9000's vs 7KD at 1ohms for music.

nice readout's. :)

It really sucks that there is a 10 min limit to edit. Go here for edited version that may answer some questions. I probably edited it 10 times. lol
Stetsom 7kd 16v, 7kd 12v, New 7k2d 12v compared.

Nice job Jeff we will be doing some tests on the 1000.1 12v version within the coming week i will post results as soon as they come also.

Excellent tests Jeff... thanks for sharing them! :D

Sweet, my 7K2D's were also .5 dB higher @ 18 volt than the older versions so its good to see that gain right down to 12 volt set up's.

nice job jeff! id like to see what a new nsb90 could do!

New NSB could expect .5db. Last year when I compared the NSB vs. the CS9000 on one amp it only .3 or .4db.

Got more of an answer about this. After some brain storming we forgot to factor in efficiency into the power numbers. Reason that power numbers are so close is because the difference in efficiency between the amps.

Now I don't have a DC clamp meter so was unable to figure exact efficiency. But to give you an idea take the power of the 7kd 12v of 5200w and times it by 70% (estimated efficiency) or .7 is 3640. Then take the power of the 7k2d of 5600 and multiply it by 80% or .8 you get 4480. Now guestimating the difference in efficiency was 10% you get a power difference of 840 instead of the initial 400 before efficiency was factored in.

So I'm going to have to assume that's the reason for large spl difference and little power difference.

except it doesn't work that way because you were measuring output not input so efficiency is already factored in because the output is the output. Perhaps the differance is because the amp is simlya ble to make a cleaner signal or like you said because it holds its peak slightly longer