JE EL34 Build

[Richard]

Originally Posted by colin.hepburn

Hi Richard
Yes I found it odd as I had the 470k in on the last working rebuild I did I will recheck the value and correct placement should be after the cap to ground pleas correct me if wrong
thank
Col

Hi Col, Yes that looks fine. The -3dB roll off for that RC coupling as drawn is 3.4Hz so should give you full bass.

If your resistor is 47K though the coupling will be 10x higher at 34Hz and that would give lighter bass. If it was 470R the roll off would be 3400Hz so no bass.

If the cap value is wrong it will affect things in a similar way. If the cap is really 0.01uF the coupling would be at 34Hz etc etc.

Interesting though using just one of these components without the other into the almost infinite impedance of the grid will cause almost no loss of bass even if it's a wrong value by several times.

So I'd recheck the cap and resistor values or simply swap them out for new ones close to your drawing and see if bass returns