Implementing potentiometer into my Phono Preamp

[oRIDDLERo]

Hello everyone! I'm hoping to get some direction here, thanks for any constructive advise!

My Current Setup:
LP>Tube Phono Pre-Amp>Tube Amp(no line level outputs)> Stereo Speakers

Goal:
Stop stressing out the tube amp with lower frequencies (less than ~100HZ) and send them to a self-powered subwoofer letting the tubes focus on mids and highs.

My First Stupid Plan:
Split the signal from the phono preamp, install two 100hz FMODS on one side of the split to stop the bass from getting to the amp, the other side of the split gets sent to the sub. Why was it stupid? No synchronized volume control between the sub and the main speakers... fail.

My New Plan:
Either implement a miniDSP 2x4 HD or attempt original split/FMOD approach while adding a potentiometer to the phono-preamp stage to act as a master volume control. (the main power amp volume will be set static to ~75 of max volume)

So on to the questions!

• What do you think of my new plan? If you have a better idea i'm all ears.

• If you think my plan seems like a decent one, I need some direction as to modal and resistance range potentiometer recommendations. The Preamp is a YAQIN MS23B, and outputs .5v Thanks Again!

Some Pics of the setup:

 

[mjf]

hello,
........perhaps a "buffered volume control" like the pass b1 buffer......

 

[oRIDDLERo]

hello,
........perhaps a "buffered volume control" like the pass b1 buffer......

Interesting, I've not heard of these, looking into it now! Maybe something like this (between the phono preamp and the Split to FMODS or miniDSP? : HiFi 12AU7/6N11 Valve Tube Preamp Stereo Audio Buffer Ref Musical Fidelity X10-D 977388147897 | eBay

 

[dangus]

Sounds like the right thing would be an active crossover made with tubes, perhaps the Marchand XM-26:
XM26 Vacuum Tube Electronic Crossover Network
But it might be sensible to try a solid-state crossover first, to test out crossover slopes and frequencies and orders before spending real money. You should be able to rent a DSP speaker management processor from a music store, like the Behringer DCX2496.

 

[adason]

Active crossover inserted after the phono preamp would work, but it introduces more electronics in signal, which may or may not be beneficial.
Minidsp is just ok, not the best sonics.
B1 buffer with original transistors, modified with two outputs, one for active sub, one for power amp with high pass would be almost transparent. You can get board and original transistors from np.