[sdiazmun]

Hi!!!

Im just build two EQ573-II and they work and sound amazing!!!

The only thing I don't know if it is normal, is small changes in the frequency response when the EQ is ON, but not EQ is applying.
Also, when I select some LF frequency, the signal level falls off.

You can see this in the attached images

Thanks!!!

[JPK]

Your images do not show the attenuation units in dB. So it is difficult to tell if it is normal or not.
The normal attenuation at 16kHz with the EQ in and kHz on OFF should be less than -0.7dB.

Same thing for the bass attenuation: How many dB's is it at 63Hz.
Some attenuation or boost (1-2dB) is possible when a frequency is selected because the 12 o'clock mechanical position of the pots is not guaranteed to be the exact electrical 12. But this boost/attenuation should be the same at every frequency.
If not the case you probably have an issue with the 220Hz band. Is this frequency boosting/cutting normally?
Check the solder joints of C35, C36, SW4, J5a, J5b.

[sdiazmun]

Sorry, is true that the attenuation not shown. Is about -1dB aprox, and the two units have the same behaviour. All EQ bands works well and after your comments I asume they are ok. 

Thanks!!!!