This is a tube pre-amp using Mu-Stage. It use 6DJ8 + 12BY7 mu-stage and 5Z3P rectifier tubes. I use lot of chokes inside also and good Jenson capacitors. The casing is 100% aluminium and is self make one.
Update Sep 22, 2010:
I have upgraded the internal capacitor using some Russian PIO capacitors like KBG-I 0.01u, K40Y-9 0.22u and MBGO 0.25u. The sound become more transparent! Now this preamp is a good match for the OCL PCM1794A DAC! It introduces all the taste of tube on the sound.
See last two pictures above.
I also attached the reference document for this Mu-Stage pre-amp. I use the circuit in the last figure on page 9. Enjoy!
I also take a FFT measurement as below: Output at 2Vrms 1kHz, filter 20 to 30kHz BW.
FFT measurement mu-stage preamp SE