Installed bulk foil resistors in phono amp

But how high can you go? You can’t keep increasing the value hoping for more and more rejection! Maybe the designer deemed 1k enough.

@noromance 

That's right. With a 12AX7 10K still gives you plenty of bandwidth. In guitar amps that value is a lot higher, as the intent is to roll off the input considerably more.


LEDs can work quite well to set up the bias.

It won’t attenuate the signal at all. Its not a matter of input resistance as it is input capacitance. This is also known as ’Miller effect’. The input stopping resistor does two things- it attenuates RFI by acting as a simple high frequency filter in conjunction with the input capacitance of the tube, and it prevents reflections from the signal coming in the grid and then ’bouncing back (’reflected’) to the input circuit. The latter can cause oscillation and instability, which can cause ticks and pops in a phono preamp. By increasing the stopping resistor value this latter issue is addressed.

Yes, I've heard good things about that tube.
A 10K grid stop resistor will give you considerably more RFI protection.

Good. What's the input tube?

Any stopping resistors at the input of that preamp?