Hello and welcome!
A couple of questions:
1) Where is the antenna mounted?
2) Which direction is it pointing?
3) How long is the cable from the antenna to the amp and from the amp to the TV/VCR?
In the meantime, here are a few comments about your setup:
>> The EZ-HD does not appear to have much gain. It's physically too small to have much gain. In order for an antenna of this size to work, it probably needs to be installed outside as high as possible. If you are trying to make this work from inside the building (e.g., living room or attic), you probably need a bigger antenna. The transmitters are only about 20 miles away, but they are partially blocked by mountains (example can be seen
here), so the signals are weaker than normal.
>> For optimum results, you need to install the pre-amp as close to the antenna as possible. If there's a lot of cable between the antenna and the pre-amp, then you are losing some signal quality before the amp gets a chance to boost it.
>> The AP-8700 is a good amp with plenty of gain, so there's no need to upgrade to a different amp. Instead of investing in a better amp, you are probably better off investing in a better antenna.
>> Make sure your antenna is pointed at compass heading 310ยบ. You should be able to pick up all the stations down into the "yellow" zone on your list. There are more channels available in other directions, but you probably won't get them unless you install a larger antenna and an antenna rotator.
Good luck