Consider Connectors

“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

Amplifiers on the bench

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

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

QUAD 33 restoration (Pt 1)

The Quad 33 preamplifier is 50 years old, now.

It was introduced by Quad Electroacoustics in 1967 (to partner the 303 power amp) and 120,000 units were reportedly manufactured over 15 years.

The Quad 33/303 was Quad’s first Solid State consumer preamp/power-amp set.

My Quad 33 is serial no.6184, which means probably late 60s-early 70s manufacture. 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