Are you running Line-In or Mic-In?
If I remember correctly, using that Sony mic with only the AA battery gave me enough signal to run line-in on my pcm-m1 (without any hissing noise noticed AND without using transformers).
May be an issue with how you're running the JB3.
I second the recommendation for using the line transformers to get more gain.
That mic doesn't warrant the purchase of a UA-5, IMO.