Specifications

truly revolutionary in its concept and execution. We
have described how the input selector works and why
we have chosen FET switches (properly implemented) to
achieve the most transparent input selection short of the
Shallco rotary switches but managed to save thousands
of dollars o the retail price by making only a *very, very*
small sacrice in the sound quality.
It's the little things
that make all the dierence
At Ayre, we have always used front panel displays that
don’t generate ANY electrical noise. Instead, they are
typically either single LED’s or segmented LED’s that are
always on. The exception is the display in the KX-R which
is a special dot-matrix display that is capable of creating
Japanese Kanji characters, or even simple graphical icons.
Typically these work by addressing the pixel via a row by
column address. In order to keep an entire row or column
from lighting up, the pixels are lit in a sequential fashion,
turning on and o very rapidly - so rapidly that to the eye
they appear to be continuously illuminated.
However they cause a subliminal fatigue, and even
worse they generate a large amount of high-frequency
switching noise in the audio band. When a touchscreen is
added to this the position sensors work in the same way,
and they typically generate at least double the amount of
electrical interference. We have a computer monitor like
this at the factory that we bought to use with computer
audio systems. It is pretty much a disaster as it degrades
the sound quality signicantly to have it even turned on
in the same room.
Special dot matrix display
The Ayre KX-R uses a special form of a dot matrix display
where the illuminating phosphors are deposited directly
on top of small transistor switches with one switch
for each dot. With this mechanism, the dots are lit
continuously and the only time that they switch on or o
is when the display is changed (eg, when changing the
volume setting). Of course everything is a trade o and
the trade o here is cost. What would be a simple $10
part in the standard multiplexed conguration suddenly
becomes a $200 part to achieve noise-free operation.
That is why that is reserved for the ‘R series’ products,
which cost considerably more than the more mainstream
5 series products. Here we use 7-segment LED’s to
indicate the numerical volume control and 14-segment
LED’s to indicate the alpha-numeric characters that
display the input names.
The only Ayre products that use the electrically noisy
multiplexed displays are the products based on DVD
players, including the C-5xeMP universal audio player.
But on these products there is always a button on the
remote control that allows the users to turn the display
completely o for critical listening, and it automatically
turns back on for a few seconds when it receives any
command, whether from the front panel controls, the
remote handset, or the AyreLink communication system.
Sleep mode
And of course the same degree of care is taken with
the microprocessors that control the advanced features
that are expected on modern products. The control
processors are always in “sleep” mode, whereby the
master oscillator is completely turned o. When a
command is received, it is detected, and this “wakes
up” the µP, turning on its clock (which is essential for its
operation as it carries out its instructions step-by-step. As
soon as the command has been executed, the processor
returns to “sleep” mode and the oscillator is turned o
once more.
" As more and more manufacturers have
followed Ayre’s lead of making balanced
components, four of the six inputs on the
AX-5 are balanced. "
If a customer requires additional single-ended inputs,
Ayre sells high-quality single-ended to balanced
adapters. But the converse can only be made with
expensive and imperfect transformer coupling. So we
have chosen to include a full complement of balanced
inputs.
t: 01727 865488 e: [e-mail] w: www.symmetry-systems.co.uk
Symmetry, Suite 5, 17 Holywell Hill, St Albans, Hertfordshire AL1 1DT
Page 13
The AX-5 Story
from Ayre Acoustics March 2014