Monday, December 3, 2012

300B monoblock with interstage


This is my humble 300B with interstage transformer, made by me with a lot of helps from my shifu, the circuit very simple, WE437A as driver-interstage (5k-5k. 1:1) then 300B in cathode bias then OT  (3.5k:8 Ohm)
WE 437A is a single triode by Western Electric, old tubes, hi gain, long life, the best one for interstage amplifier.

Power supply provided by GZ 34 as rectifier - ASC x386S - Choke - Mundorf M-Lytic.
Transformer provided by local transformer factory, bifiliar and also interleaves winding.
IEC Socket, power switch, industrial standard, a gift from my friend, who's have an electronic shop in our city, Surabaya.
Resistor by Takman, will try another brands later.
Humpot by Violet (100 Ohm) will changes later with resistor in series formation, because my humpot position exactly in center position.
300b Cathode R by Dale, and can't wait for Caddock came from ebay
300b Cathode bypass by Rubycon BlackGate 100uF
437a cathode bypass by Elna Cerafine 470 uF
Binding post, female chassis RCA by CMC, this is the best for me (for my pocket actually)
Chassis using 5 mm aluminum sheet for top plate, insert plate (below the 5 mm) is 3 mm aluminum sheet.
Wood chassis material is Rosewood, 25 mm thick, a gift from my friend.
The craftman by my Shifu's assistant. The result is very good isn't it??
The result is total weight more or less 20kg each monoblock!

Sound? Very good for me, vocal and hi very extended, bass is tight because of the Full Music 300B/c Carbon Plate, My humble opinion for this tube is aristocrat sound, very polite with extended vocal and hi, maybe this Full Music 300B/c for somebody with audiophile's ears. Will change later with Full Music 300B/n Mesh Plate, because of my Shifu's influences, I'm now looking for extended bass that I can feel with my chest, not just my ears, and more musical.

Please minds, this is my personal opinion.
Bass head with tubes? yes, maybe...