an image to enlarge.
Balanced mains units:
Nene Valley Audio (NVA) BMU 1000
Russ Andrews BMU 3000 MKII
IsoTek Aquarius EVO3 & Sigmas EVO3
During a recent vinyl exploration session at my
home I asked a learned friend to describe his musical experience
in just two words? He responded quickly…“Organic and
After many years of listening, trial and error,
I am happy with all areas related to my hi fi components, cables
and much later room treatment. I even had a radial circuit with
a double socket fitted specifically for my hi fi components when
I moved into my home twenty years ago. The challenge now is to possibly
get MORE from my components whilst maintaining the organic and engaging
Balanced mains units (BMU’S), Mains conditioners,
purifiers, regenerators, silencers… Like many components and
accessories reportedly linked to improving your musical experience,
mention any of the above to hi-fi & music enthusiasts and you
will receive varying comments, advice, opinions and facial expressions.
I was advised by many respected hi-fi enthusiasts “not to
bother, or stay clear of A, B or C”. However, if I have learned
just one thing over the last half century and a bit of my life,
I have learned what works for one, may not work for another. It
is a rare that a component (or scenario) is a one size fits all
solution. I will invariably do the opposite of what I am advised
(in the hi-fi world) and try for myself before making a decision
and handing over my hard earned cash. BUT, if my findings are similar
to those who advised me, I will always acknowledge their findings!
Companies such as IsoTek, Russ Andrews, PS Audio
and Belkin have been championing mains conditioners and various
filters for many years, however, only a few companies have extended
their range to include balanced mains conditioners (BMU’S)
There is definitely a growing Balanced Mains Movement
in the world of home hi fi which has been gathering pace in the
last few years. Mains conditioners have also grown in popularity,
however, the latter does appear to have as many fans ‘as well
‘Supplying your system with balanced mains
offers an unrivalled way to dramatically reduce mains noise and
improve the sound quality from your system – that’s
why balanced mains are common features in recording studios…’
‘…The mains supply is distorted
by numerous factors as it travels from power stations to be distributed
throughout our homes, eroding the performance of high-quality audio
and AV systems. As the electronic devices we use proliferate and
the demand for electrical power intensifies, the quality of the
electricity we feed our systems continues to slide…’
I initially contacted Airlink Transformers, Richard
Dunn (NVA), Russ Andrews, Signature Audio Systems (PS Audio’s
UK distributor) and Nick Poulson (Isol-8) and advised each of my
existing component list. I also advised I had an open mind regarding
Thank you to Airlink Transformers and Richard Dunn
(NVA). A huge thank you to Stephen Oakes (IsoTek), Russ Andrews
& HI FI Pig’s Dan Worth for your continued patience and
Airlink Transformers assured me their units were
being used successfully by many professional recording studios and
they supply toroidal transformers to ‘other’ companies
who sell BMU’S. However, they could not offer a trial of any
unit as they make units to order. So, after much thought and further
research, I decided continue my search elsewhere.
Nene Valley Audio
(NVA) BMU 1000
My first experience of a balanced mains unit (BMU) came via the
NVA 4 socket 240 volt, 1000 watt BMU. Richard Dunn form NVA was
confident his 1000 watt unit was all I needed to power my set-up.
Considering my Musical Fidelity M8 power amplifier is 500 watt per
channel (2000 watt total power output) alone, I was cynical. This
simple, but aesthetically pleasing unit collected by myself direct
from NVA’s headquarters in Kent has its own built in standard
cable and plug with four UK sockets ready for use. I initially utilised
all four sockets on the BMU plugging in my M8 power amplifier, M8
pre-amplifier, phono stage and turntable power supply. As I had
recently enjoyed John Coltrane’s commanding and spiritual
tenor from the album “Crescent” (John Coltrane Quartet)
on vinyl without the BMU in place, I felt this would be a great
way to test and hopefully immerse myself even further within the
Quartet’s message. Unfortunately this was not to be. Coltrane’s
commanding tenor was almost reduced to a humble squeak and McCoy
Tyner’s normally precise piano was now as vague as a politician’s
promise. The overall result - a compressed lacklustre musical presentation!
Further experimentation and trial of various component
combinations with the NVA BMU revealed that it worked wonders with
my amplifier, preamplifier and internally upgraded Musical Fidelity
A3 CD player. In fact, CD reproduction was on a level I had never
heard before in my home (or most other homes or hi fi shows). Resolution,
textures and depth were described by another music lover as “non-cd
like!” Unfortunately, as CD is not my main source, it was
obvious this BMU would not work for me as a final choice. However,
I suspect this NVA 1000 watt BMU could possibly work its magic if
your set-up total wattage output is within a specific range AND
with a retail price of just £500, this BMU is without doubt
superb value, so a 30 day trial is recommended!
Russ Andrews BMU 3000 MkII
I initially set my eyes (and wallet) firmly on the Russ Andrews
BMU 1500 MkII. At £2550, this was still dramatically more
costly than the NVA 1000 watt BMU, but still cheaper than the Russ
Andrews BMU 3000 MkII (£3950). After my earlier experience
and further discussion with the Russ Andrews team regarding my components,
I was advised to try the BMU 3000 MkII!
Prior to delivery, the BMU 3000 voltage will be
factory-adjusted to your domestic mains voltage for optimum efficiency.
Russ Andrews send a voltage meter to enable 48 hour monitoring of
the mains within your property. Once an average reading is obtained,
the BMU is calibrated. ‘This is not user-adjustable but
can be adjusted free of chargeback at the factory if the need arises
– for example, if you move house.’ Russ
First impressions after delivery of this unit...
“No need for me to visit the gym today, I have just completed
a lower back workout carrying this unit from the front door to the
living room.” This dual transformer BMU is presented
within its own heavy duty hardened plastic flight case and weighs
in at a sturdy 22kg! As the BMU 3000 does not have a built in mains
cable to connect to the wall, I requested the use of Russ Andrews’
Powerkord 300 (a previous experience review winner). This is supplied
at an additional cost.
This BMU has five UK sockets available. For
consistency I initially utilised four sockets with the same combination
as before (M8 power amplifier, M8 pre-amplifier, phono stage and
turntable power supply). Once this BMU had run-in, I was able to
hear (and feel) the transformation in the musical presentation overall.
What started out as a brittle, harsh and tiring assault on the senses,
slowly metamorphosed into the most articulate, smoothly detailed
and deeply emotional connection to music of all genres. AND all
this from my preferred source ‘vinyl’!
It was important to ensure I was actually falling
in love with the improvement in the musical presentation and not
just subconsciously relieved to hear music minus the harshness during
the run-in process (or compression from the previous NVA BMU during
vinyl playback). I had not listened to music through my system connected
to the ‘standard mains’ for some time, so a quick A-B
switch was carried out at this point. As stated at the start of
this journey, a friend described his recent listening experience
as “organic and engaging!” I agree with his description
100%. Listening to music through my system connected directly to
the standard mains was still very enjoyable, however, now it was
easy to spot the missing layers and missing extra depth, especialy
with the lower octaves. I was still enjoying the music without the
BMU 3000 in place, but I enjoyed it a whole lot more as well as
discovering more about each individual recording with the BMU 3000
in place. The BIG question is;
“Could I live without the Russ
Andrews BMU 3000?”
With the Russ Andrews BMU 3000 now back in place,
I continued to revisit my vinyl collection. Donny Hathaway’s
“In performance” is not the greatest recording or pressing
by any measure, but Hathaway’s soulful gospel yearnings transcend
such technical challenges and reaches out to all at the Troubador
in Los Angeles California (and beyond). I have always been able
to completely immerse myself within the joyful participating audience,
or ‘zone in’ to be with the man himself and wish for
a “Sack full of Dreams.” (Final and favourite track
on side two). With the Russ Andrews BMU 3000 in place, I get a greater
sense of Mr Hathaway’s positioning and presence within the
auditorium, as well as feeling just a few spiritual steps closer
to the man (and his fellow musicians). With eyes closed, toes tapping,
I feel even more involved in this momentous performance than ever
I continued to explore other vinyl favourites, such
as Rachmaninov’s “The Four Piano Concertos / Rhapsody”
Vladimir Askkenazy – piano, London Symphony Orchestra conducted
by André Previn (Decca). Again, I was struck by the greater
depth as well as greater orchestral space. Askkenazy’s piano
position and key strikes were also clearer and more precise with
the BMU 3000 in place.
For many years CD has just been a ‘convenience
source’ for me. I have attempted to sit in my listening chair
for longer than ten minutes with any CD playing, but often failed.
I have listened to various CD players in various environments over
the years with multiple price tags, but always walked away feeling
cold. After my positive experience with the NVA BMU, I was eager
to hear what would happen to CD reproduction with the BMU 3000 in
I was not disappointed. Kurt Elling’s rich
baritone from the album “nightmoves” combined with beguiling
bass interplay with past collaborator Rob Amster on “The Waking”
was nothing short of magical! Depth, detail, vocal textures and
realistic individual instrument separation, combined with that
‘non-cd like’ presentation from a cd player I had
almost given away a few months ago. The big test is if I felt impelled
stay in my listening chair for longer than ten minutes? Well, I
can confirm, six CD’s later… I only actually moved to
change CD’s. I have become so involved with my CD collection,
I probably would not get up to answer my front door if Jenifer Lopez
rung my doorbell…
‘well actually, the last bit is
not quite true..!’
I have to confess - I read two reviews on
the Russ Andrews BMU 3000, as well as reading the info provided
by the Russ Andrews newsletters prior to taking delivery. I shrugged
my shoulders at the reports of various improvements to reviewers’
listening experiences and I winced at the price tag.
I live without the Russ Andrews BMU 3000? At this point, the answer
is an emphatic “NO!”
IsoTek Aquarius EVO3 &
IsoTek Sigmas EVO3 mains conditioners
(These units have also been described as mains
filters or / and mains purifiers).
The Aquarius EVO3 is IsoTek’s best-selling unit with a retail
cost of around £1500. The Sigmas retail price is approximately
Before listening to my system with the Aquarius
EVO3 or Sigmas EVO3 units in place I went back to basics. I reluctantly
removed the Russ Andrews BMU 3000 and returned to standard mains
for some time. This would help to insure I was comparing the musical
presentation to standard mains only (for now)!
Both Aquarius and Sigmas have six sockets
each available for use. Two sockets (16 amp) in the red coloured
panel area for high powered components (amplifiers). Four sockets
(10 amp) in the black panel area for other components such as pre-amplifier,
CD player or DAC. Power switches for each unit are placed underneath
the bottom panels which help to keep each unit aesthetically pleasing
to the eye.
The Sigmas EVO3 front panel houses a digital
display highlighting either the incoming voltage to your home, or
the (THD) total harmonic distortion on your mains (before filtering).
The display data can be switched via small black buttons on the
lower front panel (one switching the display off).
Both power conditioners took just over a week to run-in, settling
down and getting past the brittle and harsh presentation.
Utilising four sockets with the same combination
as before (power amplifier, pre-amplifier, phono stage and turntable
power supply) I found the Aquarius had little impact on my musical
experience. After trying various combinations (disconnecting amplifier,
connecting CD player and / or phono stage etc) without much impact,
I decided to concentrate on the Sigmas EVO3.
It was intriguing (for a while) to watch
the varying voltage changes throughout the day on the Sigmas digital
display. The voltage entering my home varies from 239V – 249V.
The THD (total harmonic distortion) also varies depending on time
of day (less in the morning) increasing when more electronic items
are switched on around the house (and my neighbour’s house).
The THD also increases depending which source I am using. Using
my CD player seems to increase harmonic distortion into the mains
supply. I tried to search for more information regarding THD and
what figure relates to high distortion. IsoTek do not provide any
information or documentation and I was unable to find anything more
on the net. Time to listen to music…
With the Sigmas EVO3 in place, I could definitely
hear a ‘difference’ in the presentation. However, it
was not immediately clear if the difference was as an improvement!
Just as with cables, interconnects or any other
addition to your system, you not only need to decipher what the
addition has added to the musical presentation and listening experience,
but just as importantly, what the addition has taken away!
For many years I have received positive feedback
from viewers and friends who either own IsoTek conditioners, or
have experienced IsoTek’s conditioners at various hi fi shows.
One viewer commented “… the Aquarius is the most
significant non hi fi component upgrade he has made to his system
to date!” In fact, it was this above comment that encouraged
me to start this ‘mains experience’ journey.
I continued listening to various recordings on
vinyl with the Sigmas in place and noticed the musical presentation
was less forward with a slightly wider soundstage than what I was
used to when my system was directly connected to the mains supply.
The same occurred when listening to CD. This experience was neither
negative, nor positive at first, though I found my attention and
focus began to wonder as time passed. I began to experiment with
various combinations (as before). I even attempted to use the IsoTek
Sigmas EVO3 in conjunction with the Russ Andrews BMU 3000 (Connecting
amplifier/ pre-amplifier and source components across both units).
This did not produce a tangible difference, or any favourable listening
experience benefits. The best and most pleasing result came when
I used the Sigmas with a small pair of ‘very cheap’
bookshelf stand mounted speakers for a short period (instead of
my MartinLogan Scenario ESL’s). For some reason the soundstage
widened substantially as well as an overall improvement in clarity,
focus and note decay.
Once my MartinLogan Scenario ESL’s
were back in place, I decided the Sigmas EVO3 was not for me!
As you may already know, hi-fi, components
are not a ‘one size fits all’ situation…
The Sigmas EVO3 is by no means IsoTek’s most
elaborate mains conditioner. IsoTek have a variety of even more
sophisticated units, not to mention power cords and audiophile-grade
connectors. Results and listening experiences will always vary.
Perhaps I will have the opportunity to try another IsoTek power
conditioner (though I suspect my bank manager would warn against
I purchased the Russ Andrews BMU 3000 (with Russ Andrews’
Powerkord 300) and placed the unit on a specifically designed shelf
at the side of my system for ideal mains cable access.
I continued my BMU exploration
and was able to acquire another specially designed 2500 watt bespoke
unit with a private designer. This Special Edition BMU with my personal
logo now powers my Rel T5I subwoofer and has further fine-tuned
both lower (and surprisingly) top end frequencies. Bass is even
tighter and more articulate (especially double bass). Though some
may see this improvement as subtle, my ears, soul and wider smile
believe this addition is worth it. My listening experience has improved
The overall improvements gained: Greater clarity
to all areas of the musical spectrum. The human voice sounds free,
less choked. (Excuse the pun). Greater depth to lower frequencies
(deeper bass). Improved musical timing overall. More cohesive soundstage.
Greater space and air between notes and individual instruments.
Without doubt this is the most difficult experience
review to date. The cardinal rule of not making too many changes
at one time was broken on several occasions while testing various
BMU’S and power conditioners. Above is just a selection of
the many units tested! Some changes were forced upon me (turntable
breakdown & MartinLogan ESL breakdown forcing me to use the
cheap bookshelf stand mounted speakers for a short time). Other
changes were self-inflicted, such as changing circuit breakers from
16 to 20 amp at the consumer unit. All repairs, adjustments and
changes took time to settle (run-in) before I could reasonably continue
testing. One thing for sure, I have has used more combinations in
the last few months than the Enigma machine code breakers during
World War II, AND more power combinations than Tesla!
Complete system details:
AMG Viella V12 turntable with AMG Teatro MC & AMG reference
Phono stage & interconnect cables. Whest PS.40RDT Special Edition
phono stage with Cambridge AudioAzur XLR cable.
Musical Fidelity A3 CD player (internally upgraded). Van Den Hul
The Second Analogue Interconnect cables.
Musical Fidelity M8-500S power amplifier with Musical Fidelity M8PRE
Luminist Revision Poseidon XLR balanced cables.
Martin Logan Scenario hybrid electrostatic speakers. Chord Legend
REL T5i subwoofer.
Quadraspire Q4 EVO turntable wall bracket. Quadraspire Q4 EVO 4
© Michael Valentine Studio
April - May 2019