EQ pedals can be useful in certain circumstances (e.g. as a solo boost), but if you don't like the basic sound of your guitar straight into your amp (and feel that it is the amp, rather than the guitar which is to blame) then it would be far better to do something with your amp (modify it or just get a different one entirely) than trying to cover up poor tone with electronic stuff.
This is such a common mistake - people have a sound in their head that they want but when the set-up they have fails to deliver it, they try to improve things by further degrading the purity of tone with gizmos, rather than looking at the two most important, basic elements (guitar + amp).
Bad tone + unnecessary pedal = worse tone
Have you considered that your speakers might be too 'dark'?
When was yur amp last serviced? If it's years then the caps, etc might need changing
Or maybe you just have the wrong amp for your needs.
