tuning my amp?

The 40V is the measured output to achieve 800W into 2-ohms. This concerns gain setting and has nothing to do with the amplifier's power supply.Support the12volt.com

So how do you explain to the OP how he gets 800W into 2 Ohms at 14.4V? It sounds to me as if you are saying he just tweaks some magical gain setting that "amplifies" the 14V etc to 40V. soundnsecurity IMO gave the correct answer with "voltage on the input gain does not equal power out. they are independent of each other" which admittedly I interpreted as "voltage of the amp (or on the input) is independent of its output voltage". I merely added how the amp achieves the voltage required for such output. IE - that amp has an internal 40V DC bus/supply. IMO there is nothing complicated about it. 12V high output amps have SMPS aka dc-dc converters to create a fixed higher voltage supply. The "amplifier" section with its gains are independent of that and do their usual volume and gain stuff.

i think the OP was a bit too vague. i assumed he was talking about rca voltage, which is why i wrote "voltage on the input gain" which is what i thought the OP meant because he is talking about tuning an amp. i thought maybe he thought that he needed a certain amount of voltage at the low level RCA input to get a certain amount of power out, possibly a misplaced variable while trying to work out a formula. my answer might be sort of right but it was for the wrong reason

I'm not aware that RCAs had 14.4V.... Like I said, I thought the OP's question was clear - a straight question about Ohm's Law etc. But IMO no point continuing (meaning it's not my call that I answered his OP in part or otherwise). I'll reply if mantasuk requires.

RCA's dont have 14.4v under normal conditions. they do make high voltage line drivers though.

And how do those high voltage line drivers produce the 800W @ 2R, or how should the OP use them for to adjust his gains? Incidentally, I suspect the OP has left the building.

oldspark wrote: And how do those high voltage line drivers produce the 800W @ 2R, or how should the OP use them for to adjust his gains?

they dont... people use them with the belief that they increase the power the amp puts out because it basically makes the audio louder at a lower volume but usually wont increase the final maximum volume, unless you count the extra distortion they can create.

You miss my point - I know that! Paraphrased - the input voltage (whether RCA voltage or the DC supply) is irrelevant to the unit's output.    Feel free to answer the OP's question about setting gains etc though IMO that has already been answered. I have merely stated how a 12V device pumps 800W into a 2 Ohm load. End of story.