Note: This page is originally derived from Derek Walton's parts page as well as Angela.com's 300b parts page and serves as a reference for exploring alternatives parts and corresponding prices for building a similar (if not identical) 300B Monoblock amp.
Quantities are for dual mono construction - i.e. two amps.
Angela Capacitors are manufactured in Denmark by Jensen, as indeed AudioNote are and weather they are marked Audionote, Angela or Jensen they are identical except for the label thereon. They are an paper in oil, aluminium foil type, but I have used the paper in oil,copper foil one for the siganl bypass section. For the power supply section I have used Angela Polypropylene and oil which is manufacturered for Angela by the same company - ASC - that supplies the like of Conrad-Johnson and are highly regarded in the Japaneese audiophile ranks.
Jensen Tobias Jensen Ltd. was established in 1917,... thats 84 years ago, in the same year the Great October Revolution laid the foundation of the Soviet Union. Today the USS don't exist anymore, but Jensen are still manufacturing electronic capacitors, which have been developed through the decades of the electronic age. Over the years, good quality, high reliability and long life expectancy have become the central part of the company philosophy. Many years of experience, a staff of qualified experts, an advanced production equipment supported by an extensive control system (ISO 9001) guarantee a high level of quality.
Output Transformer Oh dear.....there was a lot of thought into this one. There are so many opinions out there that it can be a minefield to the inexperienced like myself. I spent so long debating it that it held me up for months as my initial feeling was to go for one of the more expensive, more upmarket makers, assuming that they real good ones are more expensive. But it just kept me from ordering and it was getting silly , so instead I opted for a sensible choice in the form of the Hammond 1627SE, which has air gapped laminations and weights 11lbs. The use of interleaved windings helps to maximise the high frequency responce and have an excellent bass responce.
Hammond traces its roots back to 1917 - some 84 years ago, co-incidentially the same as Jensen above - and was incorporated as Hammond manufacturing in 1927 and currently has a turnover of $166million and employs 1,200 people. In the 1930's, Hammonds previous years experience was to put them in the forefront of the manufacture of magnetic components during World War II for communication transmitters and very specialized transformers and the beginning of the Cold War in the 50's thrust upon the Company significant volumes of military transformers, especially as a result of the construction of extensive early warning radar systems across Alaska, Canada and Greenland.
Their ratings are for full power at the rated plate current and their specs are +/ -1dB rolloff points - 20-20KHz , again at full power, as well as having a tested HV rating of 2000VAC. These models use a "distributed air gap" to eliminate core saturation and high quality M6 grain oriented silicon steel laminations.The multiple interleaved secondaries allow 4, 8 or 16 ohm load impedances .
Power Tube The 300B....First developed by Western Electric as an audio device in 1935 is still one of the most linear audio tube ever made - need I say more. For the first 6 mths I used the JJ Tesla but have replaced it with Western Electric...beyond belief and worth every penny.
Signal Tube General Electric 6SN7GB.....Good alround tube, though somewhat lacking in the lower octaves and is a little forward and somewhat "in your face"
RCA Red Base 5692.....a sweet alternative to the 6SN7GB and one that some will say is the very best of its type. Absolutely superb and my best recomendation for this amp. Though very expensive, it has a wonderful midrange and better bass tonal definition.
RCA Black Base 6SN7 GT ....they all have their own benifits and while this is a sweet tube with a good extended top, it is no match for the Red Base
Rectifier I have used the 5U4GB General Electric tube for this amp but have also tried a Mullard GZ34 and found that there are some benifits brought with it in terms of bass definition and an increase in the top end , presumably because of the increased B+ due to the lower voltage drop across it of around 20v - I finally setttled on the 5U4GB for better sonics and what seems like better drive overall. The 5U4 GB has a voltage drop of 44v across it and is 1970s vintage.