Do I need to use back to back diodes on the B- rail as well as across the meter ?? I use one meter for both plate and grid current. See I told you it was a dumb question. Tnx Ed W3NR --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.443 / Virus Database: 248 - Release Date: 1/10/2003