I want my EQ and Compressor to run in Stereo pa naman sana so I connected to the Main Mix output of the mixer. The output of the compressor went direct to my Konzert Amplifier
That is the right connection. You don't have to follow what I mentioned on the tip coz you don't have pre-fader output on your main mixer.
You can achieve same result by setting your input source to Unity gain (0) on their slider and also a unity gain for your Main Mix slider (0).
Of course you need to set your amp to the lowest so that it won't be too loud because you are sending full signal now from the mixer to the 2600 and 1502 which is also a full signal to the amp.
Since your mixer don't have PFL to set unity gain properly for your source inputs, you just rely on the Gain control level to avoid clipping by monitoring the clip Led. I just found out on your mixer that there is no Gain control for the Stereo inputs.
You don't need to play around with the Aux Send/Return for this :)
This a tutorial how to set unity gain----><click here for link>