The gain pot is an unusual value of 370K. I made certain this value is correct. When I breadboarded the circuit, I tried a 250K and a 500K. I noticed the 250K sounded identical to the BJFE, whereas the 500K increased in gain too quickly, and became muddy. This may partially explain why the MP version sounds so different. If you truly want to emulate the 370K pot (I couldn't find this actual value pot anywhere), you can use a 2M pot (smallbear) in parallel with a 470K resistor. The upper range of the gain pot does not give much of a difference in sound, and the 250K is just fine IMO.The gain pot is an unusual value of 370K. I made certain this value is correct. When I breadboarded the circuit, I tried a 250K and a 500K. I noticed the 250K sounded identical to the BJFE, whereas the 500K increased in gain too quickly, and became muddy. This may partially explain why the MP version sounds so different. If you truly want to emulate the 370K pot (I couldn't find this actual value pot anywhere), you can use a 2M pot (smallbear) in parallel with a 470K resistor. The upper range of the gain pot does not give much of a difference in sound, and the 250K is just fine IMO.