speaking of fancy volume pot ... after a long time of searching i finally bought and got this potentiometer for my highend tu-05 build:
This is a 48 step 50 kOhm Shunt Stereo Potentiometer from Khozmo Acoustic http://www.khozmo.com .
The build quality is amazing, the red housing is full aluminium, the rotation axis is supported by ball bearings, you can adjust the torque, high quality resistors, both channels separated and seperately shielded, only two resistors in the signal path per channel. In the "Full volume" position it is just like a wire, no resistors in the signal path, just like a bypass. i will use it together with the two Sowter 10K : 10K input transformers. so no problem with a too low imput impedance.
And in comparison to other high end potentiometers it is really affordable (179 Euros).
Also i ordered but have not received yet (should arrive next week) two of this special Sowter 9351 Headphone transformers (40/150/300/600 Ohm Output Impedance):
Together with my TANGO HS5 output transformers my high end tu-05 build will have secondary tabs with 4 / 8 / 16 / 32 / 40 / 150 / 300 / 600 ohm output Impedance so i am sure never again to have any impedance range problem connecting any headphone i can think of.
in the meantime i also have selected and ordered the resistors (Vishay Dale CMF RN60), have started to build the final power supply modules (and just ordered a lot of additional filter parts and inductances to build additional AC filter stages), and lots of MKP 100µF foil capacitors and air-cored coils / inductances, so with the exception of the primary power filter modules the complete amp from LC filters to output stage is "electrolyte capacitor free" built only with MKP foil capacitors even for anode and filament voltage filtering and stabilization.
so things really come together, the only major parts i have not ordered up to now are the 50 18650 Li-Ion batteries.
Edited by GermanGuy - 4/19/14 at 3:25pm