Active filter design software

[astouffer]

Just out of curiosity could a transformer be used to mix the signals? Or maybe a tube?

I mixed 3 signals using a 6ML8 triple triode. Theres one common cathode so make it a follower with 3 separate inputs.

 

[lochness]

So could I use a 12av7 or 12ax7 with the cathodes tied together to do the same?
And would I tie the plates together? (if I did that it would kinda make it like a wunderlich tube)

 

[astouffer]

Hmmm, think I used seperate plate resistors but it shouldn't matter if your signal is coming from the cathode.

 

[lochness]

Ok here is what I have for the lowpass section (highpass and phono-preamp not shown). Sorry for the poor quality my scanner sucks and pencil doesn't scan well.The values for each low pass filter are the same. The tubes used will be 12av7. The schematic doesn't show it but it will use a transformer volume control at the output.

Does there need to be a plate resistor for the mixer? What should Rk be (40k like the rest of them?)?

 

[astouffer]

Does there need to be a plate resistor for the mixer? What should Rk be (40k like the rest of them?)?

If 40k is a good operating point for the rest of the followers it should be fine here.

 

[lochness]

Cool

Thank you for the help man!