Try it like Bryan says, with the physical resistor for R2. That should give nominal 50kOhm load to the filter. Then try it without R2. It should sound louder, but check the filter knee freq with SPL meter to make sure it's still ~65Hz.
Here's some links to good parts from mouser to verify the design:
C2C1R1R2You might wanna buy some extra caps for tweaking the Frequency, these parts are cheap and MKT1813 caps sound good enough to hear what's really happening. Shipping is the big cost if you have to order again.
If it works out the way you hope you can get copper V-Caps to match your output coupling caps.
Don't forget the pics!