Hi-Fi World – September 2019

LETTERS & EMAILS

22 HI-FI WORLD SEPTEMBER 2019 http://www.hi-fiworld.co.uk

In the July 2019 issue your

impedance plot published on page 31

for Wharfedale Denton 85th Anniversary

Edition is identical to the impedance plot

published on page 43 for Piega Premium

701, thus which loudspeaker is that

impedance plot from please? Can we

have the impedance plot published for

the other loudspeaker?

Thank you for continuing to publish

an interesting magazine.

Yours sincerely

Chris Taylor

Hi Chris. Please accept my apologies

for the duplication of impedance

traces in our July 2019 issue. The

Wharfedale Denton 85th Anniversary

Edition impedance trace (p31) was

wrong so we provide the correct

version below, together with that of

the 80th Anniversary Edition from

our archives, for comparison.

As noted in the review text

(Measured Performance) the port

frequency moves from 52Hz down

to 40Hz due to the use of a slightly

larger cabinet with more volume,

and a larger bass unit, giving stronger

bass. Port frequency lies at the centre

of the dip at left, between the sharp

peaks at either side. It was Gilbert

Briggs of Wharfedale who noted that

the impedance curve says a lot about

a loudspeaker, if correctly interpreted.

He would certainly have recognised

these classic curves, nowadays

collected in an instant by our Clio

(Audiomatica, Italy) computer based

loudspeaker measurement system.

LPs do need to be well centred

to minimise low rate wow, as you say

• a major effect. If an arm is swinging
  in-and-out visibly, once per revolution
  whilst playing, this produces vagueness
  of pitch, giving a soft focus effect. It’s
  pleasant enough, which is why belt
  drives survive, but Technics Direct
  Drive decks offer harder temporal
  focus that is more correct.
  Technics’ new SL-1200GR, able
  to accept an SME or Rega arm, and
  fully loaded with stroboscope and
  cueing light is the one to go for. Look
  at Timestep tuned versions I suggest,
  as they have knowledge of Technics
  tech and can offer a GR with arm of
  choice. NK

FM ON THE MOVE

I presume Ray Spink’s FM reception

problem in your August 2019 issue is

confined to his car, and the reception is

fine on the kitchen portable? There is

this page at https://www.radioandtvhelp.

co.uk/interference/rtis_radio has a

transmitter checker, which is useful. It

may help him and others to make sense

of reception problems.

Regards

Mike Bickley.

FUSES

I often read about the importance of

mains cables and connectors, and their

effects on sound quality. I may disagree

with a lot of it, having tried various

experiments over the past decades. But,

while we do read reviews extolling the

virtues of esoteric cables, there is seldom

any mention of that humble component,

the fuse. Every item of hi-fi equipment

comes with a mains lead terminated

with a 13amp plug (in the UK) and

every plug has a fuse rated at a few

amps. Break open such a fuse and inside

there is a thin bit of wire which melts

when too high a current is drawn.

The question I have is this. How

does such a thin piece of meltable wire

stand in the great cable debate? Even

the most powerful of amplifiers uses

power which passes through a fuse, in

fact through two or three in the average

hi-fi system if one uses socket blocks/

mains conditioner etc. And this after the

power has passed through the consumer

unit contact breakers along the path

from the power station. I have never

read any explanation of the use of fuses

in a hi-fi system.

Many thanks.

Cliff Millward.

Tipton,

West Midlands

Hi Cliff. Yes, it is all very complicated,

difficult to pin down and contentious

as a result. As you and so many

others note the path from power

station to home is a long one – or it

may not be! Some live at the end of

long power lines loaded by industrial

and agricultural equipment, others

may live close to a power station

where the feed is cleaner.

A mains regenerator such as the

Power Inspired AG-1500 reviewed

in our September 2018 issue or the

Istotek Evo 3 Mosaic Genesis we

use act as a buffer to distortion and

noise, from all lines – long ones with

potentially poor regulation and high

noise, and short ones that appear

better, but still suffer distortion from

voltage regulation – typically 3% our

measurements show. Fuses are just a

part of this complex picture. NK

The 'radioandtvhelp' website (www.radioandtvhelp.co.uk) has a

useful transmitter checker that can explain UK reception problems.

Wharfedale Denton 85th Anniversary Edition

impedance.

Wharfedale Denton 80th Anniversary Edition

impedance.