Mile High Effects
Member
- Joined
- Sep 14, 2023
- Messages
- 11
- Reaction score
- 4
I believe I’ve compiled a fairly accurate chart indicating approximate idle dissipation, idle current, and associated Mesa Color coding at ~475v Plate Voltage. This chart does not apply to Simul Class amplifiers, btw.
On my 90’s Dual Rec, I installed an external bias control to more-closely dial in the tone and response I like best; and which Mesa Color Code would reflect those numbers.
I believe the it was the designers intent of the idle plate dissipation to lie between Green & Gray although Mesa typically ships new amps and repairs with Red or Yellow coded tubes so they’ll run cooler and last a bit longer. White color coding was dropped, from running too hot for these amps, I presume?
This is taken at a plate voltage of about 475v with 124VAC coming from the wall with Silicon Diodes and Bold settings.
25w
EL34, 6CA7, KT77
6L6WGC, 6L6GCR, 5881WXT, 6Π3C-E
25% 13mA Red
30% 16mA Yellow
35% 19mA Green
40% 21mA Gray
45% 24mA Blue
50% 27mA White (dropped)
30w
6L6GC
25% 16mA Red
30% 19mA Yellow
35% 22mA Green
40% 25mA Gray
45% 28mA Blue
50% 32mA White (dropped)
Maybe @Boogiebabies and @electric mayhem can help me tweak this chart a bit if it’s a bit off? I’ve read some of the best info that was shared from their experience regarding dissipation/Mesa color coding on this forum. So thank you.
On my 90’s Dual Rec, I installed an external bias control to more-closely dial in the tone and response I like best; and which Mesa Color Code would reflect those numbers.
I believe the it was the designers intent of the idle plate dissipation to lie between Green & Gray although Mesa typically ships new amps and repairs with Red or Yellow coded tubes so they’ll run cooler and last a bit longer. White color coding was dropped, from running too hot for these amps, I presume?
This is taken at a plate voltage of about 475v with 124VAC coming from the wall with Silicon Diodes and Bold settings.
25w
EL34, 6CA7, KT77
6L6WGC, 6L6GCR, 5881WXT, 6Π3C-E
25% 13mA Red
30% 16mA Yellow
35% 19mA Green
40% 21mA Gray
45% 24mA Blue
50% 27mA White (dropped)
30w
6L6GC
25% 16mA Red
30% 19mA Yellow
35% 22mA Green
40% 25mA Gray
45% 28mA Blue
50% 32mA White (dropped)
Maybe @Boogiebabies and @electric mayhem can help me tweak this chart a bit if it’s a bit off? I’ve read some of the best info that was shared from their experience regarding dissipation/Mesa color coding on this forum. So thank you.