It all started in 1999.
47 Laboratory (Junji Kimura) introduced the 4706 Gaincard amplifier, which produced 25 Watts per channel from a single IC chip amplifier per channel.
The special features of this amplifier design were:
A ‘high-end’ dual-mono amplifier designed around a single power IC (per channel) The world’s smallest number of parts in an amplifier (9 per channel) The world’s shortest signal path length (32mm including parts lengths) The world’s shortest negative feedback loop (9mm) Smallest possible Power Supply filter capacitance (1,000uF) combined with a high capacity power transformer Continue reading
The Sennheiser HD 650 is a great headphone with a little bit of sonic ‘magic’ appeal. The attractively priced
MassDrop HD 6XX version is a special bargain.
A popular and nice match for the Sennheiser HD 650 / HD 6XX is a vacuum tube headphone amplifier.
The project here was built by Jeremy Young. It was inspired by the Bottlehead OTL headphone amp, but circuit ‘operating points’ were determined to suit a locally made power transformer.
Marc Czerwinski has a nice music system in the attic space of his home in England.
The room is a 5.5m wide x 14.5m long x 2.75m high loft-attic, with 1.2m high side walls.
The loudspeakers are 2.45m spaced apart and the listening position is 4.6m away.
With Marc’s kind permission, here are some pics of his highly-tuned music system and equipment, including:
“God is in the detail” – Ludwig Mies van der Rohe (et al)
Sometimes it’s necessary to re-examine the little things, the forgotten details. Try to dig out the last 10% improvement.
Consider amplifier and loudspeaker connectors.
We know that music signals are alternating current, AC not DC – swinging positive/negative. We know also that “current in a conductor resides at the surface at high frequency” (Prof. Malcolm Hawksford,
HFNRR Aug 1985): Continue reading
After purchasing a (Tonghui) dB-Millivolt meter, I am able to more easily (and more accurately) undertake frequency response measurements of my Preamp and Power amp.
This enables me to directly read relative dB signal voltage output from my amplifier (or preamp) without laborious 20Log Vout/Vin calculations. (Thanks to advice from my pal Clarry.)
I will check out my recently built
WOT Preamp and my usual 2A3 Push-pull amplifier. Continue reading
This ‘integrated’ single-ended 300B kit amp was introduced by Audio Note UK in the mid 1990s. This example was built by me in 1997.
The standard Kit One looks plain and unattractive, so I dressed it up with some Kondo-copper aesthetic!
Not inexpensive (around GBP799 in 1997), this was however a quite good sounding 300B SE amp.
A Directly Heated Triode PP amp can combine the harmonic naturalness of triode amplification, with the lower output impedance and good LF control of Push-Pull amplification.