Is this normal?

[shiznats]

The reason i got rid of my stock pup out of my Agile LP 2500 (les paul copy) is because it would feedback like crazy. I got an SH-5 custom and got it wired. it works fine but with my amp set at a practice setting volume (1/10 on my peavey bandit II amp) ... it feedbacks. the stock neck pickup doesnt do this and neither does my friends alnico pickup. is there a problem here? or is the output of the pickup high enough to be causing this?

thanks,

mike