5F1 output tube

[martin manning]

Ok, so you are ~11% low in heater voltage. That will cause some reduction in emission, but it's not likely to account for what you are seeing. You could connect the AC voltage and see what difference that makes, but I'd get a known good tube in there. Also, I would rectify just the LED power and leave the high current heaters on AC.

[jcool666]

The 7806 should keep the supply at 6v, I think its low because the total load is about 70 -80mA over the 1A rating of the regulator. But I'm only using the circuit to test the 7189s. Once I rewire the socket for the 6CM6 itll draw 300mA less.

[jcool666]

Turns out all 4 of the 7189s are bad. Once I rewired the socket for the 6CM6 I ended up with 41mA @340 volts for a plate dissipation of 14 watts. Havent played it yet but I was getting some hum from the 7189s and it's dead quiet now. In the future I may buy an el84, just to compare the 2 tubes, but for now I'm going to keep it as is.