These are placed on power cords in the system and also at strategic places throughout the house. Most important places - TV sets, computers, burglar alarm system, refrigerator.

Recommended: Large toroidal cores made by Amidon Associates, Santa Ana, CA. Types F-240-43 (ferrite) and T-300-2 (iron powder material).

These are available in electronic parts stores. An alternate mail order and international source is Surplus Sales of Nebraska

E-mail: grinnell@surplussales.com or URL: www.surplussales.com.

Catalog part numbers: iron cores (ICH) MM-T157-2 (page 57); ferrite cores (ICH) 57-1465 (page 55).

The toroidal cores are partially effective just leaning on a power cord and can be evaluated for system improvement this way. This tweak must be carefully adjusted and evaluated by ear. Just one core too many can tip the balance from smoother with reduced “grundge” to hard and edgy.