Hi,
I've designed and breadborded a simple 12AX7 Overdrive pedal with an lm386 as a Preamp to kick the signal into the tube.
here's a scematic of the preamp section:
http://imageshack.com/a/img901/9926/yjW03e.jpgC1 = 10µF, 25V, Electrolytic
C2 = 10nF Ceramic
C3 = 10nF Ceramic
R1 = 100K Pot

Pin 2 is not grounded, because its internally grounded through a 50K resistor.

The output goes into a 500K pot which biases the tube and brings the signal in.
The problem is, that the lower frequencies are very distorted, so the lower notes sound horrible when they're palm muted.
I have tried to change the capacitors and got a better sound when i changed C3 from 10nF to 100pF (Ceramic), i could only hear the highs. that was better, but it was not as powerful and it had no bass at all. Have i configured the LM386 wrong? do i need Film caps?

The Valve works and sounds perfect, i bypassed the lm386 and i got a wonderful sound which of course had nearly no distortion/overdrive.
So here's the big question: How do i get the LM386 to sound good?