PG RSD 1200.1 output

Havoc · Post by **Havoc** » Thu Jun 19, 2008 12:39 pm

Hey guys,
I have a RSD 1200.1 amp and im looking to figure out how much volts I should be reading at the output terminals. I am trying to apply the formula ( sqrt of the amp power rating times ohm load) to figure it out and would like someone that knows to double check my math. Here is what I come up with: 1200 * 3 (JL 12w7) then find sqrt = 60 volts. Is this even in the ballpark for this amp / sub combo? Thanks for any input.
Havoc

Post by **Bfowler** » Thu Jun 19, 2008 1:26 pm

well the amp is rated for 1200 watts at 2ohms and 780 @ 4ohms....and you have to factor in the efficacy (about 80%)

so....(48volts^2)/3 = 768 watts... (48 is 80% of 60volts)

and (56 volts^2)/4ohma = 784 (rated power)
(49 volts^2)/2ohms = 1200.5 (also rated power)

and so then... 80% of X = 53 (53 is about middle road of the two)

X=66.25

i would run it right around 66.25 volts @ 3ohms to get max RMS power.

someone feel free to set me straight if this is wrong

Post by **stipud** » Thu Jun 19, 2008 2:00 pm

Efficiency? WTF Brian. That shouldn't be part of voltage calculations for configuring gains. A 1000w A/B amp and a 1000W D amp should both produce the same voltage, even though their efficiencies are totally different.

V = sqrt ( watts * impedance )

So assume about 1000 watts for 3 ohms...

V = sqrt ( 1000 * 3 ) = 54.77 volts

Post by **Bfowler** » Thu Jun 19, 2008 2:05 pm

well color me stooopid....i don't know why that seemed like a smart thought earlier.

Havoc · Post by **Havoc** » Fri Jun 20, 2008 12:39 pm

Ok so by that formula, sqrt(1200 * 3) = 60. I am running @ 50 volts right now at the outputs and want to overwork the amplifier. Running @ 60 will give me full output from the amp and be safe from over driving and/or over heating correct? Thanks for the quick response guys!

Havoc

jasie02 · Post by **jasie02** » Fri Jun 20, 2008 1:14 pm

1200w is for 2 ohm load, not for 3 ohm load. 1000w for 3 ohm load is very reasonable, which would equivalent to ~54.77v.

Post by **Bfowler** » Fri Jun 20, 2008 1:24 pm

jasie02 wrote:1200w is for 2 ohm load, not for 3 ohm load. 1000w for 3 ohm load is very reasonable, which would equivalent to ~54.77v.

agreed, it the average of the 780@ 4ohms and 1200 @ 2 ohms is 990

Havoc · Post by **Havoc** » Fri Jun 20, 2008 4:01 pm

Thanks for the help guys! I will set the output to 54.7v and lock it down there without worrying about cooking the amp. I apprecaite all your responses.
Havoc