Musical Fidelity MX HPA User Manual

HEADPHONE PREAMP

REPRODUCED FROM HI-FI NEWS | www.hifi news.co.uk

A

nyone who listens seriously
on headphones at home must
eventually discover the limitations
of a computer headphone output,

or, if they are still using one, an old-style

hi-fi integrated with headphone amp built
in. So the boom in headphone listening
has brought a big wave of dedicated
headphone amplifi ers. Musical Fidelity

has already come up with more than one

solution in this fi eld, but its most ambitious
model yet is the still-affordable £599
MX-HPA reviewed here.

In fact the MX-HPA is the fi rst model in
a new series. MF’s slogan for the MX range
is ‘High-end in sound, small footprint’, and
the MX-HPA is certainly a lot smaller and
slimmer than the well-known M1-HPA or its
recent successor, the M1-HPAP.

At the same time, this ‘ultra
performance headphone amp’ naturally
aims a lot higher than the budget V90-HPA
[HFN Jan ’14]. According to Musical
Fidelity, the MX-HPA is signifi cantly more
powerful than its budget sibling even
though its ‘1.8W/8ohm’ specifi cation is
not directly comparable with the 32ohm
rating often quoted by competitors.

FULLY BALANCED OPERATION

Power is only a small part of the story, of
course, but even though the little V90­HPA’s output will be more than enough in

practice, experience suggests that more

power capability does make for better
sound. But now we come to the MX-HPA’s

main special feature, which is fully-

balanced operation.

Most domestic audio equipment uses
unbalanced or ‘single-ended’ connections
between units, typically using RCA phonos,

which mean that one of the two
conductors carrying the audio signal is

connected to the chassis or ‘ground’.

In balanced working, the two signal
connections are both independent

of the chassis ground. Using a three­pin connector for each channel allows
for a separate screen around the two

conductors in the cable, and this is

connected to ground.

Balanced operation was long-

established in the pro world before it was
taken up in high-end audio, because it
allows the use of very long cables without

interference or loss. Balanced pre- and

power amplifi ers have been commonplace
for decades now, but more recently there
have been moves to adopt a balanced

connection for domestic headphones.

It seems that from a technical point

of view, the benefi ts may not be clear­cut, as KH explained in his review of the
Auralic Taurus MkII [HFN Jan ’15]. But
characteristically, Musical Fidelity has

spotted the trend and fearlessly acted upon

it. Unfortunately, perhaps, the twin-XLR
option provided by the MX-HPA isn’t the
only way of doing it [see boxout].

However, Musical Fidelity boss Antony
Michaelson has mentioned that there may
be another product soon featuring the
alternative 4-pin balanced connection.
(While Musical Fidelity will soon be
releasing its own balanced headphones,
the new MF200s are not equipped with
balanced cables.)

MX’S CLEAN STYLING

You can’t fault the fi t and fi nish of fi nish of
the MX-HPA, as it gives every appearance
of solid build and high-quality construction.
That eye-catching crystalline-textured
silver-satin fi nish looks clean and smart

RIGHT: Driven via a compact, low-noise

switchmode PSU, the heart of the MX-HPA

is a fully balanced Class A preamplifi er offering
an overall gain of x8 or x15

Claiming ‘ultimate’ performance, Musical Fidelity joins the balanced brigade with this

slick and compact headphone amplifi er – the fi rst model in a new ‘MX’ range

Review: Steve Harris Lab: Paul Miller

Musical Fidelity MX-HPA

Balanced headphone preamp

Made by: Musical Fidelity Ltd, London

Supplied by: Musical Fidelity Ltd

Telephone: [phone]

Web: www.musicalfi delity.com

Price: £599

www.hifi news.co.uk | REPRODUCED FROM HI-FI NEWS

A BALANCED MARKET?

and doesn’t seem susceptible to fi nger­marking. As a styling feature, a sort of
double facet in the front panel emphasises
the large volume knob.

Even so, the fascia is dominated as much

by the two headphone output sockets,
bigger than the usual ¼in (6.35mm)
headphone jack. These two sockets have
a dual functionality because each of them
can accept either a standard ¼in jack plug,
or a 3-pin XLR.

For balanced

operation, if you have
a pair of headphones
equipped with separate

3-pin XLR connectors

for the left and right
channel, you will use

both sockets for one pair
of headphones. More

usually, though, when using the ordinary

(unbalanced) ¼in connection, these same

two sockets provide stereo outputs for two
pairs of headphones.

There’s no need to switch between

balanced and unbalanced output

operation, as the sockets will make the
appropriate connection depending on
which plug you insert.

Next to those big sockets are three neat

little toggle switches. One of these is a

gain setting switch, providing a gain boost

if required when using higher-impedance

headphones. This operates on both output
sockets, so although the MX-HPA will cater
for two listeners at once, it doesn’t provide

independent control of gain setting.

As the MX-HPA caters for balanced
inputs too, the back panel carries a pair
of three-pin XLR sockets for L/R channels,
as well as the usual RCA phono sockets
for unbalanced sources. Another of the

small toggle switches on the front selects

balanced or unbalanced

input mode.

For this review

Musical Fidelity kindly

loaned a pair of its

MF-100 headphones,

and while I feel these
are great value for
money, I did most of my

listening with the truly excellent Sennheiser

HD 650s. These have been on the market
unchanged for many years now, but they

are still a reference in their price category.

ORGANIC PRESENTATION

With the HD 650s, the sound via the
MX-HPA was enveloping and also full of
textured detail. On a well-produced album,

you would hear instruments and voices

growing organically out of the ambience.
For me, it was this aspect that really set the

ABOVE: A reassuringly ‘analogue’ volume

control governs the output from two ‘combo’
XLR/6.35mm headphone sockets. Gain and
RCA/XLR inputs are switched via toggles

If you’ve yet to hear a pair of headphones using balanced wiring, don’t worry as
you’re in the majority. Almost all headphones still use the standard (unbalanced)
¼in stereo jack connector, with an adapter to fi t the mini-jack socket on most

computer and portable devices. But since the US specialist company Headroom

launched its Blockhead balanced headphone amplifi er back in 2001, other
specialists have followed suit, also offering to rewire existing ’phones with

two three-pin XLR connectors. But despite their enthusiasm, there are few

commercially-available headphones using this connection format. You can buy a
balanced headphone amplifi er and headphones from Oppo, for example, but this
uses the simpler option of a single 4-pin Neutrik connector to give the necessary
separated conductors for the left and right channels. Sennheiser also went for a
4-pin balanced connector on its HDVD 800 headphone amplifi er, and has offered
suitable balanced cables for its upper-range models. Essentially, there’s still no

industry standard for balanced headphone connections.

MX-HPA such a big cut above the couple of
lower-cost headphone amplifi ers I initially

compared it with. I also felt that with the

MX-HPA the Sennheisers gave a feeling of
effortless bass power when the recording
called for it, and offered more sheer bass

extension than I would have expected.

If you wanted to relax with lush

orchestration and romantic vocals, the

MX-HPA could really deliver. When I put on
‘Say It Over And Over Again’ from Diane
Panton’s Red [Inakustik INAK 9129 CD], the
whole package was put over beautifully.
The singer was close-up and intimate,

complete with her delicate Stacey Kent-like

vibrato and endearingly nasal nuances.

Patricia Barber’s The Cole Porter Mix
[Blue Note 50999 5 01468 2 6] includes
one of the songs covered by Panton:
‘You’re The Top’, although her version
could hardly be more different. On Barber’s
own song ‘Snow’, which starts just with

voice and piano, her voice is presented

naked and free of any artifi ce, and I could
only marvel at the subtlety and mastery of

harmony and dynamics in her deceptively

simple piano accompaniment. Listening
to the whole album with the MX-HPA
brought a fresh appreciation of Barber’s

individuality and the rapport she has with
her tight-knit group.

With a beautifully-produced album like
Eric Bibb’s Get Onboard [Telarc CD-83675],
the MX-HPA could give a truly natural,

satisfying sound, with a deep and richly-

populated soundstage around the head. As
usual, Bibb creates different instrumental

colours for each song, starting with the

combination of spooky gospel choir and
grungy guitar on ‘Spirit I Am.’ On every

track you would appreciate the little extras
that help tell the story in an appealing way,

from the distant slide guitar on ‘Promised
Land’ to the muted harmonica, electric
piano, clarinet and banjo that sneak in

‘There’s a sense of

ease which makes

the music totally

absorbing’