Archive for the ‘Tube’ Category

Mu-Stage Preamp Tube

Sunday, September 21st, 2003

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!

Mu Stage Reference Document

I also take a FFT measurement as below: Output at 2Vrms 1kHz, filter 20 to 30kHz BW.

FFT measurement mu-stage preamp SE

300B Tube

Thursday, February 13th, 2003

Everyone should own a 300B amplifier once in a life!  I am one of them.  This is quite a big and costy project and I use all the good stuff that I can afford at the time – Lundahl transformers, choke, Jensen Cap, Elna caps, Multi-cap, Rifa cap, telfon wires and Full Music 300B tube etc…  Total spend on that is about US$1200!

Full music tube is lack of bass.  Recently I buy a Quiguang 4300B and the bass is much better and firm.  The 4300B cost about US$120 per pair.  I think 300B to drive mid and high frequency is one of the best sound amplifier!

Update: Oct 1st, 2010

The 300B was upgraded with Russian PIOs, see first picture.  FFT measurement is attached below:

FFT 300B final