Adding negative feedback control?

[ylelevier77]

I’m looking to convert the 27k resistor used for NFB in my SF vibro champ to a 25k linear pot. Figured I’d pull the 27k resistor and go from the speaker into the pot and then back into the circuit at the 47ohm resistor. I’m going into lug 1 and out of lug 2 back to the 47ohm and grounding lug 3. But it’s not really working. The taper ramps up quickly and then plateaus if that makes sense. What’s the proper wiring? Feeling like a total noob here. 

[pdf64]

You may find that an audio taper control is more to your liking.
However, having the series feedback resistor adjustable down to 0 seems like asking for malfunction when set very low.

[sluckey]

First off, it's not a 27K resistor. It's a 2.7K resistor. I would experiment with a 10K pot on series with a 1K resistor.

[thetragichero]

a no load pot might be put to good use for this too, no? that way not only do you have an adjustable nfb resistor but also the option for no nfb (although i suppose this would make any presence pot not very useful)

[PRR]

You want zero to 100%. This is a job for a pot.