Adrian

4 ohm speakers and effect on power delivery.

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I often get asked about this and some speaker manufacturers like to avoid stating average impedance when they quote speaker sensitivity…

In 2002, Paul Messenger described beautifully the paradox of 4 Ohm speakers.

‘Over the years, speaker makers have tended to evolve their designs to suit the typical transistor amplifier which is essentially a voltage source with a low source impedance.

Halve the speaker’s impedance from 8 to 4 Ohms and the speaker draws twice the current and power from the amplifier. This extra power gives an increase in apparent (though mythical) sensitivity. Once one manufacturer adopts the strategy, others feel obliged to follow.’

A 4 ohm speaker actually draws 2W when provided the voltage required to provide 1W into an 8 ohm speaker so a 93db 4 ohm speaker is no easier to drive than a 90db 8 ohm one!

Mild steel support brackets. £150

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PAIR OF MILD STEEL SUPPORT BRACKETS. 6MM WALL MOUNTING  PLATES DRILLED FOR ANCHORING TO WALL (CHECK BEARING CAPACITY OF WALL PRIOR TO INSTALLATION AND FIXING TYPE) 50MM X 50MM X5MM MS ANGLES WELDED TO PLATES TO PROVIDE SUPPORT. UPPERMOST BRACKET ARMS WITH THREADED BOLT ADJUSTERS FROM BELOW TO ALLOW LEVELLING (SUPPLIED). (LOWER BRACKETS NO ADJUSTMENT- USE SHIMS / SIMILAR (NOT SUPPLIED) IF ADJUSTMENT IS REQUIRED) BRACKETS ARE DESIGNED TO BE FINISHED WITH SAME PAINT AS WALL PLANE TO BLEND IN, AND AS SUCH, WILL COME WITH RAL 9010 MATT DULUX PAINT COLOUR PICTURED.

Gold Note CD-7 with top of the range Favard upgrades. £1200

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The compact CD-7 was always very musical.

This is a custom-built one-off Gold Note supplied to me with upgrades from the top of the range Favard including its Burr Brown PCM 1792A DAC, components of its power supply including the power regulator and OP as well as the Clock.

The idea being to have a really compact CD player of superior quality.

DIMENSIONS: Width 200mm  x Height 80mm  x Depth 260mm

Superb and at my cost price.

‘SME’ RCA plugs.

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Many years ago I used to curse the overly complex 4-5 piece RCA plugs which were often referred to as ‘SME’ plugs.

I don’t know if SME made them but they were dreadful.

Often attached to arm leads the wires would shear, come loose and cause all sorts of intermittent problems.

The screen wires were trapped by a threaded portion which would soon enough break off the filaments or develop a loose connection.

To my surprise, some Chord cables use a similar design of RCA plug with a plastic outer casing.

My Chord iChord lead has been very unreliable with the centre pins sometimes sticking in the socket and the plastic body sliding off the plug (hence the ugly glue fix) and the same issues with the screen- pinching piece needing tightening and the screen coming detached.

Now, the last straw, the earth has sheared causing a rare drive-unit to be blown…

 

Peerless 100-20 co-ax drivers – offers

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Rare 9 inch drivers with tweeter on frame in front of bass-driver dust cap.

Alnico magnets.

Not the first time I find a good co-axial driver outperforms a good full ranger. E.g. Visaton B200, Fostex etc.

Peerless did not bother replying regarding driver parameters but sensitivity seems very high.

Original Jensen caps (which measure fine) supplied but have replaced them just in case. – see image.

Audioflair

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There has been some confusion about our status. We never traded as Audioflair Ltd. We applied to be a Ltd Co to protect the Audioflair name but it remained dormant until it was voluntarily dissolved by us in 2016.  I have always been a sole trader and still am.