REPRODUCED FROM HI-FI+ ISSUE 30

Dynavector P75 Phono-stage
by Jason Hector
In issue 24 I attempted the job of testing
four phono-stage solutions at the lower
price end of the spectrum. It turned out
to be very instructive and demonstrated
that a few pounds can make all thedifference, as can the specific aims ofthe designer. My personal favourite
turned out to be the MM only Graham
Slee Era Gold at £400, give or take apenny. Mind you I didn’t remotely hear
all of the options in a wide open field,with devices like the Tom Evans Microgroove an obvious contender. At aprice of £450 the subject of this review,the Dynavector P75, is entering asurprisingly competitive market placeconsidering we are talking about aniche product in a niche market.
A cursory examination reveals
that the Dynavector follows similarlines to the stages I looked at
before; a small unpretentious box
for the stage itself and a separate
power supply. A "wall wart" type inthis case, which supplies a basic DC
voltage to the phono-stage. At thispoint the similarities start to end as theDynavector designer, Jonathon Davies,
has gone in a very unexpected direction
with the rest of the power supply.
Most audio electronics make useof standard power supplies, usuallyconsisting of a big transformer to step
the mains down, followed by a rectifier(achieving AC to DC). Then some sort ofsmoothing (usually through capacitive
storage of charge) and if you’re lucky alinear regulator to remove as much of
the rest of the ripple on the ideally DC
lines as possible. The other common
type of power supply that seems to be
spreading through audio, albeit withmixed results, is the switch mode
supply. Switch mode supplies offersome very obvious technical benefits
but commonly these have always beenused to make cheaper, smaller, lighter

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and more efficient products for mass
market applications (PC power supplies
are the most obvious). In operation,
switch mode supplies chop up (orswitch) the incoming power lines at ahigh frequency making an AC signal
which can then be rectified and filteredto DC. Because switch mode supplies
operate at this very high frequency(100’s of kHz is normal) they do notrequire such large components, orexpensive linear regulators, to achievesmoothing and regulation of thegenerated supply rails. To put it anotherway, to achieve a given power supply
specification smaller, lower specification(and hence cheaper) components canbe used and this is the attraction to theconsumer electronics companies thatuse them. In audio applications a better
regulated (lower rail noise and faster)
power supply can theoretically be madefor the same money than the equivalent
traditional supply: same benefit,different emphasis. The Achilles heel ofthe switch mode supply is the switchingitself. If the supply is not adequately
designed you run the risk of generating
noise into the circuits being powered.
Dynavector believe so strongly thatthey have solved the noise issues with
their implementation that they havedecided to include the switch mode partof the power supply inside this phonostage right up close and personal to theamplifying electronics. Considering aphono-stage is designed to handle thesmallest signals in audio (MC cartridgeoutputs) any noise from the power
supply would be a disaster. So the P75
power supply really comes in twohalves. The raw mains AC is stepped
down and rectified to DC in the wallwart supply already mentioned andthen this DC supply feeds the switching
DC to DC converter and regulator.
Because of this stacking of the two
supplies Dynavector claim that thequality of the wall wart supply and the mains itself will have no
impact on the performance of thephono-stage: big claims indeed.
Looking at the circuitry inside thephono-stage it is apparent that thesupply is well thought out using a novel
input PCB transformer, made possible
because of the 250kHz operating speedof the supply. Placing the supply thisclose to the amplifying circuits reduces
the impedance between them, always
a good thing.
All of the loading and gain settings
are programmed inside the P75 byshifting jumpers around. A word of
warning is needed at this point,
especially if you are of the ham-fisted
tendency, the jumpers are small andtightly packed in amongst the rest of thecircuit components. Adjustment almost
mandates the use of haemostats and isa job ideally suited to your dealer whoshould have the necessary tools and willknow the best settings for your cartridge.
The P-75 offers settings for both MM(also for MI and high output MC) andlow output MC cartridges. The gain
setting for MCs is either 60 or 63 dB

REPRODUCED FROM HI-FI+ ISSUE 30

which makes them suitable for cartridges
with outputs of 0.2mV or 0.15mV
respectively. The loading can also beswitched between 30, 100 and 470 Ohms
in low output MC mode. The MM mode
offers 40dB of gain (suitable forcartridges with 2mV output) and offers
the usual 47kOhm loading. Capacitiveloading is not adjustable in either gain
regime.

I’ll start thediscussion ofsound quality byrecording my initial
reaction when it entered
my system: Dynavector TeKaitora in a
Well Tempered Reference which at thetime fed a Dynavector amplification
chain (consisting of a P100, L100 andHX75) all terminated with a pair of
Shahinian Obelisks. Home territory for
the Dynavector, but you can expect anaway match in a forthcoming issue.
The diminutive P75 simply replaced
the P100 and, initially, I used its outof the box settings (63dB gain and
100 Ohm loading). On to the deck
went the excellent Diverse pressingof Richard Thompson - Old Kit Bag.
Initial observations were that the P75
was something a little bit special.
Immediately obvious was the detail it
was allowing through and the sheer
dynamic power the P75 could bring tothe proceedings was very impressive
indeed, maybe a little too impressive.
Playing more records revealed a slighthardness and a lack of the organic
nature possessed by the P100, mostobvious in the mid-range. Fortunately

this negative aspect to the sound was
relatively short lived and over the next
few hours (into the early hours of thenext morning) the stage settled down toa much more even sound. The powerful,
dynamic attributes were retained but thehardness was replaced by a relaxed but
accurate presentation, never fatiguing
but still full of detail. The P75 continued
to improve over the next 24 hours but
after that it seemed to stabilise quickly.
However, it always seems to need a fullday to return to its maximum
performance after
being switched
off for any
lengthy period.
So once the P75
was settled in andconnected up using
my preferred bullet
plugged microphone
cable I settled down withit to just listen to music. Since
the P75 was in my system during arather hectic period for me, this review
has been delayed a few times
which has been quite
pleasant because I have had
the opportunity to listen to
it in great depth and inanother, albeit similar(Well Tempered andDynavector) system.
The P75 is best
characterised bywhat it lacks …
Firstly it lacks
noise: background noise isimpressive by its commendably low
value, especially when the amount ofgain available is considered. Instruments
materialising on a low-noise backgroundstrike you as more realistic even if thegenuine recorded ambient noise is high.
Secondly it lacks a constrained
dynamic range: from large transients(just listen to a well recorded drum kit
like the one on the Kings of Leon –Youth And Young Manhood) to thegentle caress of a whispered voice,the range, contrast and speed of attack

are exemplary.
Thirdly it lacks mechanical timing:by which I mean that the P75 fails toimpart or impose any false sense oftiming on the music and this meansa wider gamut of emotions arepresented to you irrespective of genre.
The construction of the P75 is simple
and innovative (why waste pounds on
expensive cast or machined and printed
front and back plates when PCBs can dothe same job very cheaply?) and a little,
well, basic. In this area the Lehmann
I looked at before leaves it and the restof the competition wanting. The restof the case is steel which the designer
prefers because it gives improved
shielding, both of the super sensitive
circuitry inside and to stop any of thatswitching noise escaping the box with
unpredictable results. Round the backthe inputs and outputs are all phono
sockets. A small (and difficult to usewith bare wire) earth binding post isprovided. This may or may not beneeded and if used you need to ensure
there is a path to ground from the P75
since it floats in normal
operation.

In my system
and location I didn’t need it
but in another location the binding post,connected to ground, was necessary to
avoid some hummmmmmm.
This Dynavector stage has a further
trick up its sleeve. Not content withoffering the traditional gain and resistor
loading the P75 includes a mode called
Phono Enhancer which is a reworking ofa technique invented by Dr. Tominari ofDynavector Japan. This mode gets

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REPRODUCED FROM HI-FI+ ISSUE 30

rid of the input resistor, found in almost
all other phono-stages, and configures
the P75 to act as a current amplifier. The
result is that the coils of the cartridge seean effective short circuit as load, theideal condition. Within the Phono
Enhancer mode there are three gain
settings but the actual gain level
achieved in this mode is dependent on
the output impedance of the cartridge.
The Phono Enhancer mode is only reallysuitable for cartridges with low output
impedance. Unsurprisingly, Dynavector
Japan’s cartridges from the 17D2 upward
have the necessary low impedance.
After familiarising myself with thestandard MC settings I switched the P75
over to Phono Enhancer mode. Cripes,
what a difference! I was obviously
expecting a different sound and in thisassumption I was partly wrong andpartly underestimating the differences.
Phono Enhancer or Dr. T. mode lifts thisstage’s sound quality to new levels andprice brackets (but remember, this is in
the context of my Dynavector TeKaitora).
The sound produced is still characterised by the great dynamics, neutral
rendition and ease of listening shown in
the other modes. In other words it’s still
the same phono-stage, but it is simply
a better version. You can dissect thechanges wrought by moving a few
jumpers; more bass with even better
control, more detail - but it’s the way
these things are incorporated into thewhole picture that so impresses me inthe standard gain modes. Phono

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Enhancer does an even better job.
Listening to Suzanne Vega - 99.9F
Degrees or Holly Golightly – Truly She Is
None Other in Phono Enhancer mode
and we are more aware of their vocal
intonation. In both cases the frequently
complex backing instrumentation mademore sense because of the ability toresolve and integrate the music into awhole. If you aren’t resolving all of thedetail then you aren’t hearing all of themusic in the grooves. But its not that
simple, and conversely if a systemdoesn’t keep everything together in timethen all the extra information is wasted
and it can even distract from themessage the performer is trying to getacross; No such concerns with the P75.
Instrumental tonality was up there with
my P100 (and the Lehmann) and that is
impressive. There is no greying out of
the richness of acoustic instruments,
and the differences between guitar
amps, for example, are plain to hear.
Playing an old favourite is always
instructive because you really knowwhat is in the grooves, or at least you
think you do. Amongst many others(including a new pressing of REM –Automatic For The People which sounds
great, and numerous returns to the J. J.
Cale and Steely Dan back catalogue)
I cued up Lloyd Cole – Mainstream andsettled back. The result? Effortlessemotional involvement from a soundthat just flows into the room. This reallyhighlights what the Dynavector P75 is
all about - musical neutrality.

I have really enjoyed owning andusing the Dynavector P100 stage but
the P75 has equalled (and surpassed
in some areas) its predecessor’s
performance for a third the price, agreat achievement. I think there is avery real risk that the P75 will beoverlooked on grounds of price; it’s
simply too cheap to appeal to somebig-spending audiophiles. But thatwould be a huge mistake. Buy one ofthese little beauties and I can guaranteethat the CD player will be seeing a lot
less action from then on.
T E C H NI C AL S P E C I F I C AT I O NS
Low output MC – Standard:
Input Sensitivity:

0.2mV or 0.15mV

Gain:

60 & 63dB

Loading:30, 100, 470 Ohms

Low output MC - Phono Enhancer
Input Sensitivity:

As aboveGain:As above

Loading:Zero Ohms

High output MC, MM and MI
Input Sensitivity:

2mV

Gain:

40dB

Loading:

47kOhms

Dimensions (WxHxD):
Price:£475

UK Distributor:
Pear Audio
Tel. (44)(0) 1665 835862
E-mail. john@pearaudio.com