Alembic F2B tube version PCB

[rankot]

It is grounded because the pedal use 9V DC power supply, and datasheet for 12AU7 says that if I connect heaters in parallel so they can use 6.3V, then pin 9 must be connected to ground (which is also connected negative side of my supply). It is just normal 9V DC power supply.

When I put the tube in socket, voltage across R9 is 4.7V, and voltage on pins 4&5 is 4V.

[rankot]

OMG, I found out what is confusing me - my resistor is 5W 18 ohm, not 10! Digits are fuzzy, so I read 10, but when I calculated voltage drop, it became suspicious, so I measured resistance and it shown 18 ohm! I will put one more in parallel with this one, and I hope that voltage will be fine then. Thanks for trying to help me, and you actually did - I did some basic calculations and found out that the resistor is making problems.

Now, question for experienced DIYers: shall I leave this version with resistor, or make transistor+zener regulator, regarding power waste?

[PRR]

Stay with resistor. Regulation is silly, and more heat.