Roberto Petti
The beta Indra cables have been
tested extensively in three different (reference) audio systems,
including my personal one. The whole process took more than one
month, including the break-in periods. The test systems were
already deeply optimized (including room treatments, supports and
accessories) since they are used to evaluate and develop audio
equipment. First of all, let me say the results were fully
consistent in the three systems and all people involved in the
tests described the effect of the Indra cable on the sound in the
same way. I believe this is an important point, allowing a more
objective description of the outcome of the tests. In addition, we
used many hi-end cables (some of them custom built and optimized
for our amplifiers) as control samples. The best word that comes
to my mind to describe the performance of the Indra cable is
"natural", as opposed to typical hi-fi enhancements and
exaggerations. The intrinsic grain usually present in the
reproduction vanishes, leaving a smooth and extended sound. The
bass range, usually very critical, is as tight and deep as you can
expect from your speakers. The interesting thing is that this
cable does not change the balance of the systems in any way: it
"just" makes everything more liquid and realistic. The
soundstage extension and precision and the inner resolution
(details) are exceptional, although one does not notice it at
first, given the overall life-like presentation. Any of the other
(good) cables we used sounded compressed and artificial in
comparison. I must admit it was a nice surprise to hear our
systems sounding that good.
The Indra cable makes much more
easy to understand the effect of even minor changes in the system,
thus providing an effective "tool" to tune the overall
musical performance. The choice of supports, cabinets, vacuum
tubes or even electrical components like resistors and capacitors
becomes then straightforward. If there is a problem anywhere in
the system, you immediately recognize it and feel the need to fix
it. Clearly, this aspect could turn into a nightmare in either low
quality (which is unlikely, given the cost of the cable) or badly
assembled systems. For instance we had an interesting experience
in one of the test systems, related to this aspect. The whole
system was deeply optimized with a given set of (custom)
interconnect cables (two pairs between source-preamp and
preamp-amp). We first replaced the source-preamp cable with the
Indra. Although we obtained a significant improvement, we felt
there was a little lack of treble extension (a thing we noticed
only because of the very natural overall performance). We then
replaced the preamp-amp cable with a second pair of Indra and we
went back to the old balance for which we tuned the system.
Clearly, there was interdependency between cables and components
(probably due to the tuning of the sound). This fact seems to
indicate the Indra cable is really neutral and does not alter by
itself the overall tonal balance. I wish I could report some
flaws, but this is not the case. The only thing I would recommend
is to invest some R&D in the study of connectors &
soldering (if you have not yet done so). The Indra cable deserves
that. From what I've seen you are using Cardas top of the line
connectors, which are quite good, but perhaps the use of amorphous
alloys or custom designs could further improve the performance.
Usually connectors & soldering are the weak point of cables.
In summary, the experience with the Indra cable was very positive.
None of the other cables we tried could reach its performance and
it became our reference. It's very hard to give up such a cable
once you have tried it. I'd like to congratulate with you for this
exceptional product.
I must admit the more I use those
cables and the more I like them. I think they definitely deserve
special connectors...
(several months later) ... I had a chance to test the
Indra cables with the new STEALTH connectors. The difference with respect
to the old Cardas termination is quite clear, although not huge.
It's a bit like unveiling further the sound, with enhanced
transparency and details. This can be appreciated by switching
back to the old pairs. The new terminations seem to strengthen the
good points in the performance of Indra cables: lack of
compression and life-like overtones and harmonics. I tried to give
an extended break-in period to the new cables before the
comparison since the old pairs were used for quite a while. I
would say the new connectors improve the sound of Indra cables by
something like 10-15%, which of course is significant at this
level of performance. The mechanical strength of the connection
appears fine (the contact with the female RCA is quite firm)...
(more than several months
before) The experience with your MLT
speaker cables is very positive, they are neutral and natural
without specific colorations. They outperformed several different
cables we used before, although the gap was not as huge as with
the Indra cables. I have the impression all of your cables show a
similar behavior, in the sense they tend to a common musical
presentation. In particular, I appreciate their ability to match
high resolution with warmth and body, keeping an excellent balance
throughout the spectrum. Did you ever consider to build a
dedicated bi-wiring version of MLT in which the lower and upper
frequency conductors are optimized separately (for instance taking
into account a typical cross-over frequency of 1k-2k Hz)? Do you
think it's realistic to use alloys in ribbon configuration or that
would make the price unmanageable?
The M21 power cords were tested
extensively. The locking IEC connectors (15A) seem indeed a very
good solution from the electrical point of view, in spite of the
fact they do not look very nice. It seems M21 is an excellent cord
for the preamplifier, providing an improved reproduction of
overtones and harmonics and increasing the "body" of the
sound. Qualitatively, the effect is similar to a change from
digital to analogue source, although not as large. I suspect part
of the performance is related to the cryogenic treatment and part
to the cable construction itself (it would be interesting to
check). The use of M21 on the power amplifier gave more
contradictory results. I remind you I'm talking about a
single-ended triode design based upon the 845 tubes, which is
notoriously a topology very sensitive to the power supply. Note
it's not at all an "old style" tube amp since it has a
wide frequency response and a very transparent sound. The M21
performance it's good in this application as well, but, especially
if a second M21 is used on the preamplifier, it has the tendency
to slightly slow down the transient response and to restrict the
soundstage (in particular the height). A Elrod EPS3 (standard)
power cord (similar retail cost) provided better overall results
(and I wanted the M21 to sound better since it's much easier to
handle). However, I want to add a small note here. As you
know, it's always possible to improve a given amplifier or system
by using more refined parts etc. Of course this can be done only
through listening tests. Usually, if one knows live music enough,
it is quite clear the direction to go in order to have a
"natural" (and not spectacular) presentation. Now, my
comments above referred to the use of M21 in a system which was
already quite advanced in that direction. However, if we inserted
the M21 in systems using less refined parts it could help to
reduce the grain in the high frequency region (which is perhaps
the most evident effect of compromises in construction).
I've tested the connectors and
cables you sent me. A couple of weeks were needed for break-in,
during which the performance improved. Your gold over silver
plated connectors offer indeed a very low contact resistance (both
NEMA and US wall sockets) and their use resulted in a significant
upgrade of the AC filter. Subjective effects include increased
dynamics and a reduction of the perceived "grain" in the
reproduction. The M21 is very quiet when used as the input cable
of the AC filter. The Varidig digital cable was tested against the
Illuminations Orchid AES/EBU (+ other digital cables) on the
digital front-end. Overall, it provided a better timing
information (rhythm) for the music and a more focused soundstage.
It is also more detailed and extended (yet natural), although at
the very beginning it was a bit bright. Overall, my impression is
positive, the only thing that could be improved being the
subjective bass extension and body. Roberto
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