Re: K3s driving a KPA1500 - how much drive power is nominal for 1500 watts? #kpa1500

Bob McGraw - K4TAX

In doing the math, 28 watts to 1500 watts is 17.3 dB gain, while 5 watts to 150 watts is 14.8 dB gain, and 5 watts to 200 watts is 16.0 dB gain.  The point is the amp appears to be operating normally with your numbers.    Ideally, the gain of a linear amplifier is constant up to the point of compression nearing maximum output.   To better understand this, more accurate numbers would be needed.   And it is not at all unusual for an amp to have different gain values on different bands. 

Simple calculations support your observations:

dB =10log(P1/P2)


Bob, K4TAX

On 2/2/2020 8:53 AM, John Canfield wrote:
Hey guys,

Thursday the Brown Santa (UPS) delivered my birthday present for the next ten years - a KPA1500 amp. I'm slowly learning how to use it and I'm not sure if things are acting right. Going directly into a dummy from the amp, it only takes about 28 watts drive from the K3s for a full 1500 watts output. I can reduce the drive to five watts or lower and drop the amp's output to ~150-200 watts.

Does this sound correct? Thanks for any advice.

John, WB5THT

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