express and master volume

[riscado]

So I tried adding a master volume for an express circuit I built, and decided to look in Ken's trainwreck pages, I used the circuit with the single 1Meg pot, due to the lack of 500k dual pots in my stash. When I tried it, the pot doesn't seem to attenuate a lot it's either full output, or almost completely cut. I though I'd change the taper, still no luck, I don't want to use a lower value like 250k as that will mean there will always be some attenuation unless I remove the pot from the circuit, any ideas?

thanks