Vacuum tube Headphone Amp-DAC

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.

Continue reading

WOT tube Line-stage redux – Pt 1

A Line-stage With Output Transformer (WOT) was built back in 1998, a single 5687 tube per channel with output transformer (OPT).

However I failed to get rid of noise (EM pick-up and attenuator switching noise).  I lacked the expertise to optimise Grounding and to shield and/or orientate the output transformers (OPTs) properly.

Now, I have been fortunate to acquire a pair of Tango NP-126 Line Output transformers. So, I must re-visit the WOT Line-stage. Continue reading

Magic and Microphony (Pt 1)

Real music has dynamics.  Macro-dynamics – with unrestricted headroom in crescendoes.  Micro-dynamics – with subtle low-level information.

Music should be reproduced also with a ‘time’ dimension.  Not just tempo, but each sound accompanied by an harmonic ‘envelope’, where overtones are produced and decay naturally – providing a sense of ambience, dimension and space. Continue reading