an image to enlarge.
To say the last year and a half has been a
testing time with regards to hi-fi component reliability is an
understatement. When music is your sanctuary and your hi-fi components
are failing all around you, or music being played through your
system just does not sound right and you don’t know why,
life becomes much harder!
After suffering various documented panel failures
to my MartinLogan Scenario ESL speakers, it is only natural to
keep a suspicious finger pointed directly at these very sensitive
speakers. Instead of enjoying my record collection, I have spent
many months swapping various components, interconnects, mains
cables and even going all the way back to the electricity consumer
unit to test the dedicated hi-fi circuit breaker, desperately
trying to isolate the cause of sound degradation.
I can now confirm that issues such as distortion,
smearing, loss of dynamics have been caused by multiple failures
in the component chain. To make matters worse in respect of identifying
and isolating the issues, these multiple component failures were
slow to reveal themselves due to their intermittent nature. The
above issues have been caused by speaker panel failures at various
points (but now resolved with panel replacements) as well as a
slow and intermittent amplifier issues.
Cambridge Audio Edge W
Stereo Power Amplifier
The above confirmed diagnosis was finalised after
several months of head scratching (I am nearly bald now). After
receiving dozens of comments and suggestions on the back of existing
write-ups, it took a helpful brief comment from a particular member
of the Facebook MartinLogan Owner Experience Group which led me
to point a very tired finger back at my Musical Fidelity M8 500s
was fortunate to be able to swap out my Musical Fidelity M8
500s power amplifier with a loan Cambridge Audio Edge W power
amplifier (utilising my existing balanced XLR cables from
my Musical Fidelity M8PRE preamplifier). After doing so, all
sound quality issues mentioned above immediately disappeared!
My Musical Fidelity M8 500s amplifier is now
with the Audio Venue dealership in Ealing ready to be shipped
to Henley Audio (Musical Fidelity UK Distributor) for a final
fault diagnosis and fix.
Ironically, my M8 500s amplifier was returned
to Musical Fidelity (Hounslow London) a couple of years ago
after initial suspicions regarding reliability, annoyingly,
it was turned around with a ‘no fault found’ diagnosis.
A few months later I returned it to Audio
Venue in Ealing dealership, who again sent it back to me after
a two week in shop ‘no fault found’ diagnosis.
Though I was (and have been continuously) frustrated by the
lack of fault finding with this amplifier, I also respect
it was extremely difficult even for me to identify a marked
degradation in sound quality when using traditional cone speakers
for some unknown reason? Using two different models of MartinLogan
ESL (Scenario & brand new ES11a models) instantly highlighted
obvious sound degradation issues.
After using the Cambridge Audio Edge W power
amplifier for nearly two weeks (sporadically) I was eager
to box it up and return to its owner. Of course I was thankful
for the loan, however, though I found the Cambridge Audio
Edge W to be a solid punchy performer, it lacked the control,
grace and musical elegance of any Musical Fidelity power amplifier
I have ever owned or loaned (stand alone or integrated). The
Cambridge Audio Edge W also performed at its best at high
volume levels. I often have very late night – early
morning listening sessions, so need to be able to enjoy music
at low volume levels during these times. Unlike my Musical
Fidelity M8 500s (which delivers great musical performance
at all volume levels) the Cambridge Audio Edge W lacked detail
and soundstage precision at low volume levels, so I chose
to just watch television instead (a first for me)!
Musical Fidelity M6
PRX Stereo Power Amplifier (M6s PRX)*
was over the moon to be offered the Musical Fidelity M6 PRX as
a loan. As soon as it powered up and music began to flow, I found
myself being drawn into the open, warm and deeply musical landscape
offered by this extremely capable amplifier. (Again, I simply
utilised my existing balanced XLR cables from my Musical Fidelity
M8PRE preamplifier). The M6PRX definitely has a similar effortless
signature to the M8 500s and it did not sound or feel out of place
by any measure. Of course, to me there were obvious differences
in performance between the M6 PRX and M8 500s (which I would expect)
from amplifiers with a cost difference of around £1000 between
them. Slotted into my system I found highs delivered via the M6
PRX slightly softer, lower octaves to be deeper, and more rounded
(but slightly less defined). These noted differences are not a
criticism of the M6 PRX. If I owned the M6 PRX and did not have
previous experience with the M8 500s (or Musical Fidelity Nuvista
800) I would probably be dancing on the ceiling by now in complete
joy. (Perhaps not as that would mean I would be outside my MartinLogan
electrostatic speakers’ sweet spot)!
Of course my M6 PRX experience would change by
various degrees using different interconnects and speaker cables
etc. My system cable choice is set up around my M8 500s. I have
owned my M8 500s for five years+ and when it is on song, the precise
soundstage, depth, clarity and organic musical delivery offered
with both vinyl and CD playback is outstanding. The M8 500s and
other in-line components simply disappear from the mix. It is
extremely difficult not to consciously (or subconsciously) critically
judge all other power amplifiers (around this price bracket and
above) against such a high musical bench mark!
Again, none of the differences noted between the
M6 PRX and M8 500s are major criticisms due to the fact this amplifier
(as with all Musical Fidelity amplifiers) offer a musical performance
way above other hi-fi companies’ solid state offerings at
this price point.
I have absolutely no reservations in recommending
the M6 PRX.
All of the above listening tests were
conducted mainly using vinyl playback via my AMG Viella V12 turntable.
CD listening was minimal with similar results to vinyl playback.
small aesthetic observational note: As previously mentioned,
Musical Fidelity offer music lovers superb value for money with
a range of high quality amplifiers at various price points. Understandably,
decisions have to be made regarding manufacturing processes, build
materials and overall design ‘performance against aesthetics’,
to keep prices within a specific range. BUT how much extra cost
would be added to the retail price for Musical Fidelity to use
a top plate with countersunk holes to enable the use of flat headed
hex nuts (instead of round headed hex nuts)? I respect in many
set-ups, the top of the amplifier may be hidden and such a minute
aesthetic blip may not register. This design feature is still
not as bad as the infamous Musical Fidelity flimsy Christmas cracker
prize remote controls I guess!
Visit company websites for power amplifier full specifications:
*Musical Fidelity M6 PRX Stereo Power Amplifier (rebadged
M6s PRX in 2019) £2599
Power output: 230 Watts per channel
into 8 Ohms (24 dBW)
THD(+ noise): <0.007% typical
"Signal to Noise Ratio: >120dB
Frequency Response: +0, -1dB, 10Hz to 100kHz
Musical Fidelity M8 500s Stereo Power Amplifier
• Power output: 500 Watts per channel into 8 Ohms (27 dBW)
• THD(+ noise): <0.007% typical
• Signal to Noise Ratio: >120dB 'A' weighted
• Frequency Response: +0, –1dB, 10Hz to 80kHz
Edge W Stereo Power Amplifier £2499
CONTINUOUS POWER OUTPUT
100W RMS into 8 Ohms; 200W RMS into 4 Ohms
<0.002% 1kHz at rated power (8 Ohms); <0.02% 20Hz –
20kHz at rated power (8 Ohms)
<3Hz – >80kHz +/-1dB
S/N RATIO (REF 1W INTO 8 OHM)
CROSSTALK @ 1KHZ
S/N RATIO (REF FULL POWER)
Input A1-A2 (unbalanced) 1.09V RMS
Input A3 (balanced) 47k Ohm; Input A1-A2 (unbalanced) 47k Ohm
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 Kimber Hero & Kimber select KS-1116
XLR interconnect cables.
Musical Fidelity A3 CD player (internally upgraded). Van Den Hul
The Second Analogue Interconnect cables.
Musical Fidelity M8-500S power amplifier & M6 PRX power amplifier
with Musical Fidelity M8PRE preamplifier
Luminist Revision Poseidon XLR balanced cables.
MartinLogan Scenario hybrid electrostatic speakers
Russ Andrews 12TC speaker cable & Chord Legend speaker cable.
REL S3 SHO subwoofer (experience review conducted with & without
Quadraspire Q4 EVO turntable wall bracket. Quadraspire Q4 EVO
4 tier shelf.
Power & mains cables
Russ Andrews BMU 3000, Michael Valentine Studio Silver Gold Special
Edition BMU for Rel S3 SHO subwoofer,
Powerkord 300 mains cables for BMU, amplifier, preamplifier &
© Michael Valentine Studio
May – June 2020
Use the links below to read the Henley Audio & Musical Fidelity
M8 500s power amplifier test conculsion, July 2020,
Owner Experience 2,
or The System Upgrade 2015...