WOT tube line-stage redux

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

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AUDIO NOTE Kit One amplifier – upgrades

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. Continue reading

SUN AUDIO SV-2A3 amplifier

This Japanese single-ended, vacuum tube amplifier can be purchased in ‘kit’ form or fully assembled.

Power output is 3.5 watts/channel.   Supplied with Russian Sovtek tubes – 2A3 (2), 6SN7 (2), 5U4G (1).   Amplifier weight is 16 kgs.

Input Sensitivity is high (150mV), so with the in-built volume controls, this amplifier will accept Line level sources easily. Continue reading

‘Adagio’ TDA1541A non-oversampling DAC

When I first listened to DACs, I concluded quite quickly that ‘multi-bit’ DACs sounded more like music to me, than ‘bitstream’ DACs – more dynamic & ‘alive’.

The TDA1541 was originally developed by Philips (in 1985) as a high performance stereo DAC.  The ‘A’ version was manufactured between 1989-1995.  It was (is still?) regarded as one of the best sounding DACs ever made.  This chip was used in almost 100 different CD players Continue reading

2A3PP amplifier – Upgrades

This 2A3 Push-pull amplifier, built in 2009, has proven itself to be an excellent performer.  Compared with Single-Ended amps,  I am happy about the additional watts and improved bass control.

The design of an amplifier is more important than parts quality – don’t waste $$ on expensive parts in a poor design.

However, I think it is worthwhile to spend some more time and $$ on this amp. Continue reading

Magic and microphony

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