Briefly, hulda does not recommend a 1000hz zapper circuit for general zapping. Your slighly mistaken. You are referring to her circuit specs (the 1000hz) which is designed specifically for the application of "food zappicating" as well as "tooth zappicating."
Although she has said she likes the 2500hz auto-zap machine Arthur D. designs in Canada, she has still stuck with the 30,000hz frequency. In her most updated book, the 2003! Cure For All Hiv and Aids, she has UPDATED the zappers design just slightly to make certain that the waveform does not drop into negative territory at all. ALL of the info above can be read about in the book above. This book supercedes her Cure for All Diseases and even changes several aspects of her research.
You can get ALL the necessary componnents of her new design and even buy a video how to make it from...as well as the book I mentioned here:
Again, 1000hz is used for the food and tooth zappicator design.