| Acoustic Revive: RTP-4 Power
Conditioner |
| An Acoustic Revival Indeed |
| |
|
November
2008 |

I suppose if I had been told there were
sophisticated proprietary electronics inside
the RTP-4 Ultimate, virtually lossless
inductors made of pure silver foil,
capacitors manufactured of rare earth
minerals and super conductive alloys,
resistors made of carbon so pure it was
close to diamond, designed and manufactured
along lines derived from radically original
computer algorithms created by a reclusive
genius who is also a classical musician, I
might find the audible results more
plausible. None of that applies, though. The
male IEC connector (the RTP-4 requires a
separate power cord) is wired directly to
the AC receptacles. Electrically that's it,
completely passive. The RTP Ultimate series
start with an ingot of 2017 alloy dualumin.
What happens to that ingot in creating the
final product is a paean to both a
particular approach to power conditioning,
and to an obsession with quality. It's a
mighty interesting story, but if you already
know it, you may skip the next several
paragraphs.

How
it's made. The RTP-4 begins life as an
8.8 pound ingot of age-hardened duralumin, the sort
of material they use to manufacture airplane
fuselages. (The RTP-2 uses a 6.6 pound ingot, the
RTP-6 a 13.2 pound ingot.) Duralumin is an alloy of
aluminum (~95%), copper (~4%), magnesium and
manganese (<1% each). Minimizing vibration
transmission is one of the central goals of the RTP
design, and duralumin has been tested and shown to
rapidly dissipate mechanical energy. (Vibration
absorption is the conversion of mechanical energy
into heat energy.) Duralumin is also very hard: it
takes eight hours of CNC machining to manufacture
the RTP-4 chassis to a 25mm thickness. The machining
process incorporates integral mounts for the AC
receptacles; thus they are supported by the massive
chassis rather than the cover plate. Acoustic Revive
believe that a machined chassis is acoustically
superior to one put together with rivets or welds.
[Clement Perry's recent visit to Japan and the
various Acoustic Revive manufacturing facilities
confirms these claims says he. His report is due any
day and features plenty of great photos like
above].
Duralumin is even more prone to oxidizing than pure
aluminum, so once machined, the box is sand blasted,
then treated with white alumite, a very hard, high
quality anodized layer. The cover piece receives a
hairline process, a fine textured pattern, and is
then coated with black alumite. The result is quite
attractive. The bottom of the chassis is then
partially filled with powdered green carborundum.
Powdered high quality quartz and gemstone-quality
lithic tourmaline are added to an epoxy resin which
is then poured onto the layer of carborundum. The
potting mix is allowed the cure for about a week
before further manufacturing takes place.
Under test conditions using 50mm x 200mm x 10mm
material, it was found that a laminate of 7mm of
duralumin with 3mm of brass nearly doubled the
rapidity of dissipation of vibration compared to
10mm of duralumin.
Appropriately,
Acoustic Revive use four brass feet on the RTP
series. These adjustable feet are machined to accept
inserts and then plated silver. The proprietary
material inserted in the feet was developed by
Professor Masao Sumita of the Tokyo Institute of
Technology, with grant support from the Japan
Science and Technology Agency. Acoustic Revive
describe it as an “epoch making material” with an
“overwhelming vibration control characteristic.”
The
electrical outlets used for the RTP series are
Oyaide R-1 receptacles. The bodies of these outlets
are made of dark red, 30% glass filled polybutylene
terephtalate (PBT), the same extremely hard
(Rockwell 118), thermally stable material that
Oyaide uses in its plugs. The R-1s are manufactured
to Acoustic Revive's specifications, beryllium
copper internal parts plated with silver and
rhodium. Metal parts only then receive a -196 C
cryogenic treatment by a third party. (The same
procedure is followed for the male IEC connector.)
These modifications are said to improve conductivity
and what Acoustic Revive call “phase
characteristic.”
On the face of it I didn't know what to make of the
phrase, phase characteristic. Perhaps this was
references to the relative phases of current and
voltage under reactive load? Not at all. As Joe
Cohen of Lotus Group USA (importer/distributor of
Acoustic Revive products) reminded me, many aspects
of the RTP design are necessarily determined
empirically: that is to say, by listening. Existing
electronic devices are not able to detect the
perceived effects of, for example, alternate plating
materials or dielectrics. The ear is far more
sensitive. “...the movement the ear drum makes
while listening to a quiet conversation is less than
the diameter of a hydrogen atom, which is sufficient
to activate the bones of the inner ear” (Hugh
Milne, The Heart of Listening: a visionary approach
to Craniosacral work). “Phase” is commonly cited in
audio specifications, but in this case it is not
measured, it is heard. And it varies with different
plating materials and cryogenic treatment. It is the
stuff of subjectivity, an area of audiophilia I've
always tread with caution and skepticism. But it
seems to me every bit as valid as saying, “I can't
measure it, therefore it doesn't exist.”



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