sluckey wrote:Neither end of the grid stopper resistors will connect to ground. Unsolder the wire connected to pin 5. Connect one end of the resistor directly to pin 5. Connect the other end of the resistor to the dangling wire you just unsoldered. Repeat for other tube.Do I ground them to the same point the bias resistors are grounded to by adding a length of wire?
Either method will work just fine, but just to be perfectly clear... It's fine to connect the 1Ω resistor between pin 1 and 8, but you must connect pin 1 (not pin 8 ) to ground. The important thing here is that the resistor must be between pin 8 and ground, regardless of how the resistor is physically mounted. Pin 1 is not used by the KT66 so it's simply being used as a convenient tie point, similar to the way you used pin 6 as a convenient tie point to mount the screen resistors.does it make any difference having the bias resistor across pins 1 and 8 then to ground or going to ground after bridging the pins?
Either method will also work if you ever plan to use EL34s.
Those voltages look fine. Be aware that the voltage on grid pins 2 and 7 cannot be accurately measured due to the very high impedance of the LTP bootstrapped grid circuit. The actual voltage on the grid will be slightly less than the voltage on the cathode pins 3 and 8. I find it more useful to measure the voltage at the common node rather than the voltage on the actual grid.Anyway before proceeding with that here are my V3 PI values:
Thanks for that, that could have been embarrassing
Ok, so at the moment all my voltages seem fine for all my valves at all points.
is it possible I've just got a crap valve?
I put the Kt66's in my bandmaster and they seemed to work however, it's just weird that when I swap them round I get the terrible squeal.
Right I'll post back when I've properly installed the grid stoppers.
Marcus