Why is the B1-B2 dropping resistor so darn big?

[dehughes]

Sweet! I'd love to see those pics...

[lastwinj]

schematic is showing 395 on the OT node and 380 on the screen node with a 1k in between. assuming these voltages are right, then we are only dropping 15v or so across that 1k resistor. 25w is WAY overkill. 15mA and only .225w. granted this is at idle, but no way is draw going to ever see more than 5w of dissipation. i have been using 5w resistors in that place for years, for 6V6 6L6, and el34. NEVER a problem.

germ

[lastwinj]

schematic is showing 395 on the OT node and 380 on the screen node with a 1k in between. assuming these voltages are right, then we are only dropping 15v or so across that 1k resistor. 25w is WAY overkill. 15mA and only .225w. granted this is at idle, but no way is draw going to ever see more than 5w of dissipation. i have been using 5w resistors in that place for years, for 6V6 6L6, and el34. NEVER a problem.

germ

[paulruby]

schematic is showing 395 on the OT node and 380 on the screen node with a 1k in between. assuming these voltages are right, then we are only dropping 15v or so across that 1k resistor. 25w is WAY overkill. 15mA and only .225w. granted this is at idle, but no way is draw going to ever see more than 5w of dissipation. i have been using 5w resistors in that place for years, for 6V6 6L6, and el34. NEVER a problem.

germ

I'll take some measurements on my next build. On the last one, a 10W resistor blistered my power supply board and it was separated from the board by 1/8th inch space. It was VERY hot during playing (not idle). I did not take any voltage measurements becuase it was plainly obvious that it was dissipatting a ton of heat, so I swapped it to 15W (actually three 300ohm, 5W in series) with lots of air space. This was running KT77 at the time.