Date: August 03, 2008 at 23:41:56 From: Schmidlin Subject: Re: will a PT designed for a 5Y3 be OK with 5AR4?
Surprisingly, the 5AR4 heater draws a little less heater current, so you should be OK. Make sure your B+ comes off pin 8, as the 5AR4 has a cathode. Also note you should have a little more B+, drawing more power tube current, but that all depends on your design.