How can I get a clean taste while drip brewing? I have been brewing drip Coffee on different devices. Kalita and Chemex mostly. Although the results  have often been great. The biggest turn-off for me is getting an earthy, not-clean and bright tasting cup. I only use fresh specialty coffees so the problem cannot lie there. Any ideas?
The Kalita and Chemex equipment are designed for pour-over brewing. If you are using them as vessel-recipients of water from an automated dripper, it will not produce the kind of cup you desire due to the randomness at which it applies water over the bed of coffee.

If you are doing pour-over, there are a few major parameters that you will have to control to produce clean cups. Note that you will require a gooseneck kettle in order to have proper control over the water flow.

Grind. Ensure that you are using a burr grinder that is of decent quality, meaning that it can grind to a good consistency with a low number of fines. Fines are smaller granules of coffee produced in the grinding process as the beans are crushed and can over-extract to bring out bitter flavours. Your grind size should also be of medium level.

Water Temperature. This is one of the most important factors of the bunch for pour-over brewing in my experience. It's the parameter that you will change to fine tune how many compounds are being dissolved as you brew once you have a grind size that is in the right ball park. You should experiment with this as it will depend on the grind size and dose you use but I like to keep it at around 90 degrees Celsius.

Agitation. This measures how much you move and disturb the coffee. The more you agitate it by pouring, the more you continuously expose the coffee grounds to the water and encourage extraction. Controlling this will be another experimental variable for your specific parameters.

Aside from the above three that I believe to be the most important factors in what makes a clean pour-over brew, you should also take into account, the brew time, coffee-to-water ratio, coffee dose and obviously coffee origin and freshness.