Please, can someone describe the need for JFETs to be thermally coupled (seen done with a zip tie) on projects such as the DIY Audio F6, where when I look at the Pass F6 (6moons.com) board, they are not thermally coupled. Many thanks.
Fets change there parameters with temperature. If they need tobe matched ( which depends on the circuit) they should be the same temperature. if they arent using much power ( they dont warm up) they will be close ( both around room temp) and if they burn exactly the same power and are close together they will be close, But to ensure the same temp they are coupled, or you buy matched pairs on the same die ( same IC).